CHEMISTRY FORM ONE REVIEW : QUESTION WITH ANSWERS

CHEMISTRY FORM ONE REVIEW

INTRODUCTION OF CHEMISTRY

QUESTIONS:

1. multiple choice.

     Choose the most correct answer by writing its letter.

   (i) Both composition and decomposition of matter enable chemists to obtain _________ substances in our daily life.

    A: lighter

    B: heavier

    C: useful

    D: industrial

 (ii) Matter has ______ and occupies space.

    A: properties

    B: colour

    C: air

    D: mass

(iii) In chemistry subject we learn structure and __________of matter.

  A: properties

  B: composition

  C: decomposition

  D: components

 (iv) In agriculture, chemistry application helps to _______________

  A: get forests

  B: get market for crops and animal products

  C: investigate good crops and animals

  D: improve crops and animal production.

 (v) One of the following is not importance of chemistry.

   A: giving exparts such as doctors, teachers and nurses.

  B: enabling food processing and production.

  C: understanding language

  D: understanding properties of substances.

2. Matching items.

    Match items in list A with responses in list B

      List A

  (i) in agriculture

  (ii) in hospitals

  (iii) in industries

  (iv) composition of matter

  (v) decomposition of matter

        List B

A: chemistry help to get useful products from different raw materials

B: forms heavier and complex substance.

C: forms lighter and simpler substances

D: chemistry increases quantity and quality of crops and animal products.

E: chemistry provide exparts, tools and medicines for providing services to the patients.

3. Mention five substances which made as results of application of chemistry knowledge.

4. List down four importance of chemistry in our daily life

5. Outline areas where chemistry applied.

6. Define the following terms:-

     (a) chemistry

     (b) chemist

     (c) matter

     (d) composition of matter

     (e) decomposition of matter

7. The following represent composition and decomposition of matter as chemical processes in chemistry. State whether the process represent composition of matter or decomposition of matter.

  (i) AB ————-> A  +  B

 (ii) A  +  B ———> AB

(iii)  C———–> A  +  B

       ANSWERS:

1. (i) C(ii) D  (iii) A  (iv) D  (v) C

2. (i) D(ii) E  (iii) A  (iv) B  (v) C

3. Examples of substances which made as results of application of chemistry knowledge are

  -tooth paste

  -salt

  -fertilisers

  -dyes

  -soap

  -paints

  -cements

  -glues

  -paper

  -beverages

  -glasses

  -clothes

  -chalks

4. Importance of studying chemistry.

   (i) it helps in agricultural activities

   (ii) it helps in food processing and preservation

  (iii) it helps in production of medicines

  (iv) it helps in transport and communication since it applied in making tools used in transport and communication.

 (v) it helps in home care especially in cleaning.

(vi) it helps in construction activities. Eg using cement, paints and other materials of the like.

5. Areas where chemistry applied include

     -in industries

     For production of goods of different types.

    -homes

  For different activities such as cleaning and cooking.

    -schools

   By providing professional chemists.

    -farms(agriculture)

       By giving knowledge in identifying types soil and how to make a fertile and productive soil.

6. (a) Chemistry

    Is a branch of science which deals with the study of composition and decomposition of matter.

    Or

     Is a study of structure of matter and their properties.

   (b) chemist

         Is a person who studies chemistry.

   (c) matter

             Is anything which has mass and occupies space.

   (d) composition of matter

              Refers to the building up of matter.

   (e) decomposition of matter is breaking down of matter.

7. (i) and (iii) represent decomposition of matter.

     (ii) represents composition of matter

CHEMISTRY FORM ONE REVIEW

LABORATORY TECHNIQUES AND SAFETY

 QUESTIONS

1. Multiple choice.

  Choose the most correct answer.

 (i) One of the following is not laboratory rule but it is a laboratory safety measure.

  A: having adequate first aid kits in the laboratory

  B: avoiding noise in the laboratory.

  C: entering the laboratory after asking permission.

  D: avoid eating in the laboratory

(ii) Which of the following used to protect hands egainst chemicals and body fliuids?

 A: water

 B: laboratory coat

 C: Safety goggles

 D: gloves

 (iii) Is not item of first aid kit

    A: drugs

    B: Bunsen burner

    C: water

    D: safety pins.

(iv) Norbert saw the flammable sign on a box. he made the following possible interpretations. Which is the most correct?

  A: the box contains firewood

  B: the box contains spirit

  C: the box contains paper

  D: the box contains charcoal

(v) Protect and make an individual safe when he/she is working in the laboratory.

   A: laboratory rules

   B: laboratory safety measures

   C: Warning signs

   D: first aid kit

(vi) Guide and create good environment for effective investigation or learning in the laboratory.

A: laboratory rules

   B: laboratory safety measures

   C: Warning signs

   D: first aid kit

(vii) Avoid accidents by directing an individual about the uses and storage of the chemical substances.

A: laboratory rules

   B: laboratory safety measures

   C: Warning signs

   D: first aid kit

(viii) Before practical session ___________

 A: do not enter the laboratory without permission

 B: do not taste or smell chemicals

 C: report any accident however small it may be

 D: do not use dirty, cracked or broken apparatus.

(ix) After using test tubes in the laboratory, we wash them and put __________

 A: in a beaker

 B: on a test tube rack

 C: on retort stand

 D: in a basin

(x) _________ chemicals cause death immediately when taken into the body.

  A: Oxidant

  B: harmful

  C: irritant

  D: toxic.

2. Matching item.

    Match items in list A with responses in list B

     List A

(i) Used to transfer liquids into the flask.

(ii) Has symbol of cross of bones at the base of skull.

(iii) Hands protectors

(iv) Used for cooling gases

(v) Has symbol of flame with O like structure at the base

(vi) Represented by  the symbol of flame

(vii) Its symbol shows the burning surface

(viii) Its symbol shows the substance that break

(ix) its symbol is x like structure

(x) Crush substances into fine particles.

     List B

A: corrosive chemical

B: harmful chemical

C: explosive substance

D: mortar and pestle

E: thistle funnel

F: separating funnel

G: flammable substance.

H: toxic

I: oxidizing agent.

J: lie-big condenser

K: gloves

3. You are provided with the following apparatus

A-retort stand

B-glass measuring cylinder

C: plastic beaker

D: watch glass

E: test tube holder

F: plastic test tube

G: glass rod

H: glass measuring flask

J: tripod stand

K: stop watch

L: thermometer

M: mortar and pestle

N: tiles

O: crucible

P: wire gauze

Q: wash bottle

R: tongs

 Use their respective letters to classify apparatus according to

  (i) materials they made

 (ii) uses

4. Define the following terms

   (a) first aid

   (b) first aid kit

   (c) laboratory

  (d) apparatus.

   (e) chemistry laboratory

5. State the characteristics of good chemistry laboratory.

6. Explain how measurement of volume differs when using cylinder and burette?

7. It is recommended that a laboratory apparatus should be properly washed or wiped after use. Explain the significance for this when:-

 (a) measuring volume of liquids

 (b) measuring mass of the substance.

8. State the uses of the following laboratory apparatus.

  (a)Spatula

  (b) burette

  (c) glass rod

  (d) conical flask

  (e) beaker

9. List four possible causes of laboratory accident.

10. State any eight chemistry laboratory rules

11. Name components of first aid kit and state their uses.

12. Name two per each of the following apparatus

  (a) that measure accurate volume of liquids

  (b) that measure inaccurate volume of liquids

  (c) that measure volume of gases

  (d) that hold other apparatus

  (e) that hold chemical substances during experiment.

  (f) that transfer chemical substances

13. Mention four importance of first aid.
14. State safety measures that a laboratory user should take against possible harm:

15. Why are warning signs are so important?

16: Mention laboratory practices that any chemistry must be awere with them.

17. Explain six chemical warning signs.

     ANSWERS:

1. (i) A(ii) D  (iii) B  (iv) B  (v) B

   (vi) A  (vii) C  (viii) B  (ix) B  (x) D

2. (i) E(ii) D  (iii) B  (iv) J  (v) I

  (vi) G  (vii) A  (viii) C  (ix) B  (x) D

3. (i) According to the materials they made we get the following groups of apparatus

  -apparatus made of glass are B, D, G, H and L

-apparatus made of plastic are:- C, F and Q

-apparatus made of metal are:-  A, J, P and R

-apparatus made of Clay and asbestos are:- M, N and O

-apparatus made of glass wood is E

(ii)According to their uses we get the following groups of apparatus

  -apparatus used for holding are:- A, E, J and R

– apparatus used for taking measure are:- K, L and H

 -apparatus used for heating is O

 -apparatus used for the chemical reaction are:- C and G

4. (a) first aid

   Is a service given to the victim before being taken to the hospital for medical care.

     (b) first aid kit

          Is a small box in which different drugs,chemicals and instruments which are important for first aid service are kept.

  (c) laboratory

       Is a special room or building designed for experiment.

      (d) apparatus

             Are special tools and equipment which used in the laboratory.

    (e) chemistry laboratory

         Is a room or building which designed specifically for chemistry experiments.

5. A good laboratory has the following Features
6. Water supply system
7. Drainage system

iii. Electricity supply

1. Well illuminated
2. Well ventilated
3. Door open out ward

vii. Gas supply

6. Volumes of liquid differs because measuring cylinder takes inaccurate volume while burette takes accurate volume.
7. (a) When measuring volume of liquid,

    Washing helps to avoid contamination of the measured liquid with other substances whereby wiping helps to remove water content on the apparatus that may affect the volume of the liquid.

  (b) when taking mass of the substance

    Washing avoid contamination of the measured substamce with other substances whereby wiping helps to remove water content on the apparatus that may affect the mass of the substance.

8. a) Spatula

          Used for picking chemical substances which are in powdered, crystalline or amorphous form.

   (b) burette

          It used to measure volume of liquids.

   (c) glass rod.

         Used for stirring so as to mix well the mixture components.

  (d) conical flask

       Used to hold and mix chemicals during experiment.

  (e) beaker

           Used for holding, mixing and heating liquid chemicals.

9. Possible causes of laboratory accident include.

• spillage of water or liquid solution on the floor.
• use of broken apparatus.
• improper handling of the bottles containing reagents.
• use of flammable liquids on open fire.
• use of unlabelled chemical substances.
• failure in fallowing procedure or instructions

10. The following are laboratory rules

   -don’t enter the laboratory without permission

  -never take away reagent bottle from common shelf to your seat.

  -keep apparatus and table neat and clean

  -obey orders immediately

  -never throw any thing in the laboratory

  -avoid unnecessary walking, talking or moving in the laboratory

  -never taste anything without permission

  -wash your hands with soap after experiment

  -report any accident immediately however small it may be.

  -never eat or drink in the laboratory

  -don’t use laboratory apparatus for drinking or storing food.

  -avoid mixing chemicals unnecessary.

  -never go beyond instructions given.

  -put off flames which are not in use.

  -turn off water and gas taps immediately after use

11. The following items are contained in a first aid kit

• First Aid Manual

   Contains guidelines on how to use the items in the first aid kit

• antiseptic

     Used for cleaning wound and kill germs

• Soap

   Used for washing hands, wounds and equipment

• cotton wool

 Used to Clean and drying wounds

• Disposable sterile gloves

 used for preventing direct

contact with victim’s body fluids

• Liniment

  Used for reducing muscular pain

• Painkillers

   Used for relieving pain

• Adhesive bandage (plaster)

  Used for covering minor wounds

• Bandage

  Used for keeping dressings in place and immobilising injured limbs

• Thermometer

 Used to measure body temperature

• Sterile gauze

  Used for covering wounds to protect them from dirty and germs

• Safety pins, clips and tape.

Used for securing bandages or dressing.

• Scissors and razor blades

  Used for cutting dressing materials.

• Petroleum jelly

 Applied on burns and used for  Smoothening and

soothing skin.

• Torch

 Used as source of light

• Whistle Blow

  Used to call for help

• Gentian violet

  Used to treat fungal infection

of the skin and

mouth. Also used for

the treatment of

serious heat burns

12. (a) apparatus that measure accurate volume of liquids include

  -pipette

  -burette

  -volumetric flask

 (b)apparatus that measure inaccurate volume of liquids include

  -beaker

  -measuring cylinder

(c)apparatus that measure volume of gases include

  -gas jar

  -measuring syringe

(d) apparatus that hold other apparatus include

  -test tube holder

 -retort stand

 (e) apparatus that hold chemicals during experiments include

 -beaker

 -flasks

 -test tubes

 (f) apparatus that used to transfer chemical substances include

  -funnels

  -delivery tubes

  -spatula

13. Importance of first aid.

    -it helps to reduce pain

    -it brings hope to the victim.

    -it avoids infections.

    -it reduces recovery time.

    -it reduces chance for death.

14. The following are chemistry laboratory safety measures against possible harm:-

  -never carry reagent bottles by their neck.

  -never pick chemical by your bare hand

  – don’t point the open end of the test tube toward yourself or your neighbour during heating

  -never use broken apparatus

  -never use unlabelled chemicals or interchange labels of reagent bottles.

  -never look directly into flask or test tube when reactions are taking place.

  – wear protectors such as gloves, goggles and laboratory coat when conducting experiment.

  -if your hair is long, it should be tied back.

  -the soles of your shoes should not be slippery

15. Warning signs are so important because they show proper handling of substances and hazards when Miss-handling occur.
16. Laboratory practices that a chemist should be awere with include:-

 (i) experimental procedure

 (ii) apparatus sett up

 (iii) carrying out experiment

 (iv) observation and recording reading and changes.

 (v) drawing

17. Chemical warning signs are symbols that drawn on a chemical substance to show how to handle the substance and its hazards when mishandling occur.

They include

 (i) Flammable

      This is a sign for the substances that catch fire easily. It indicated by the symbol if flame.

  (ii) toxic

       Is a symbol for substances that cause death immediately after being taken into the body.

It indicated by the symbol cross of bones at the base of skull.

 (iii) harmful

      Is a symbol for substances that cause diseases after being taken into the body.

 It is indicated by X like structure.

 (iv) oxidant

       Is a symbol for substances that accelerate the burning process.

  It is indicated by the symbol of flame with O like structure at the base.

 (v) corrosive

        Is a symbol for substances that burn the body surface.

  It is indicated by the symbol of burning surface when the corrosive poured on its surface.

(vi) explosive

     Is a symbol for substances that have forceful rapid reaction which involves throwing off

CHEMISTRY FORM ONE REVIEW

HEAT SOURCES AND FLAMES

QUESTIONS

1. Multiple choice.

  Choose the most correct answer.

   (i) The following are laboratory heat sources except.

    A: kerosene burner

    B: bunsen burner

    C: firewood burner

    D: spirit burner

  (ii) Unburnt region of non-luminous flame is ________ in colour.

  A: colourless

  B: black

  C: yellow

  D: pale blue

  (iii) The following is importance of barrel of the bunsen burner.

   A: to control air that enter the bunsen burner

   B: to mix air with gas fuel

   C: to support the bunsen burner

   D: to adjust air hole

  (iv) The hottest part of non-luminous flame

   A: the outer zone

   B: the tip of outer zone

   C: the tip of middle zone

   D: the tip of inner zone

  (v) Brightness of non-luminous flame is caused by ________

      A: green zone

      B: blue zone

      C: excess unburnt air

      D: glowing carbon particles.

 (vi) Bunsen burner is the best laboratory heat source because it is ______

   A: easy to make any flame with it

   B: easy to handle

   C: free from soot

   D: cheap

 (vii) It is used for lighting

    A: luminous flame

    B: non-luminous flame

    C: charcoal burner

    D: soot less flame

 (viii) Is not found at non-luminous flame

   A: zone of unburnt gas.

   B: blue zone

   C: yellow zone

   D: pale blue zone.

 (ix) The following can not be used to distinguish luminous flame from non-luminous flame.

  A: size of flame

  B: fuel used to produce a flame

  C: colour of the flame

  D: soot production

 (x) The following are not function of electrical burner except ________

   A: lighting

   B: heating

   C: flame testing

2. Matching items.

   Match items in list A with responses in list B.

        List A

 (i) Glowing carbon particles in luminous flame

 (ii) Produced when the air hole of bunsen burner is full opened.

 (iii) It has three zone

 (iv) zones of non-luminous flame

 (v) it is used when an experiment do not need high temperature

 (vi) Can be used if bunsen burner is not available

 (vii) The choice of source of heat

 (viii) zone that burning is complete

 (ix) zone that burning is not complete

 (x) it is large in size.

    List  B

A: non-luminous flame

B: blue/green, pale blue and zone of unburnt gas

C: yellow zone, thin outer zone, colourless or inner zone and blue zone

D: Depends on the degree of the heat produced.

E: the hottest flame.

F: luminous flame

G: is yellow in colour

H: blue zone

I: gas stove

J: charcoal

K: yellow zone

L: candle burner

3. Write T for correct statement and F for incorrect statement.

(i) A non-luminous flame looks similar to candle flame.

(ii) A luminous bunsen burner flame produces less soot than non-luminous flame.

(iii) The dark zone of luminous flame consists of unburnt gas.

(iv) The hottest part of non-luminous flame may be at the top of dark zone.

(v) The yellow colour of luminous flame is formed due to presence of carbon particles.

(vi) A blue bunsen burner flame is formed when the air hole is open.

(vii) A non-luminous flame is hotter than luminous flame.

(viii) The luminous flame produces noise and is soot less.

(ix) Non-luminous flame has four parts.

(x) A yellow bunsen burner flame is obtained when air hole is closed.

4. Explain the meaning of the following.

   (a) flame

   (b) luminous flame

   (c) non-luminous flame

5. The flames that produced by bunsen burner are luminous flame and non-luminous.

 (a) which between these flames is hotter than the other? Why?

 (b) which flame can be easily seen? Why?

 (c) which flame is prefered to be used in the laboratory? Why?

6. Explain the function of the following parts of the bunsen burner

 (a) collar

 (b) air hole

 (c) base

 (d) barrel

7. (a) Differentiate luminous flame from non-luminous flame.

    (b) Outline the similarities between luminous flame and non-luminous flame.

8. Name four substances that burn and produce luminous flame.
9. (a) Mention uses of flames

    (b) Name activities that need non-luminous flame used

10. List four characteristics of

     (i) luminous flame

     (ii) non-luminous flame

11. What is the importance of luminous flame?

12. Which part of the flame is coolest of all? Why?

13. Name four heat sources that can be used in the laboratory.

14. Why the outer zone of the flame is hotter than other parts of the flame?

    ANSWERS.

1. (i)C(ii)A   (iii)B  (iv)B   (v)D

   (vi)A   (vii)A   (viii)C   (ix)B  (x)B

2. (i) G(ii)F   (iii)A   (iv) B    (v)L

   (vi)I  (vii) D  (viii)H  (ix)K   (x)F

3. (i) F(ii)F   (iii)T   (iv)F     (v)T

   (vi)T   (vii)T   (viii)F   (ix)F  (x)T

4. (a) Flame:- is a region of burning gas that produces heat and light.

  Or

      Is a visible gaseous part of fire.

   (b) Luminous flame:- is a flame which formed when burning of fuel is incomplete.

     Incomplete burning caused by insufficient supply of air (oxygen).

   (c) Non-luminous flame:- is a flame which formed when burning of fuel is complete.

     Complete burning caused by sufficient supply of air (oxygen)

5. (a) Non-luminous flame is hotter than luminous flame because formation of the flame involves complete combustion such that more heat is produced but luminous flame formation involved incomplete combustion.

   (b) Luminous flame seen easily because hot bright yellow carbon particles formed due to incomplete burning of fuel. This makes luminous flame to produce light and seen easily.

   (c) Non-luminous flame is most prefered flame in the laboratory because it is hotter and soot free.

6. (a) Collar control the air that enter the bunsen burner.

      This done by adjusting the air hole size.

     (b) Air hole

               Allows air to enter the bunsen burner.

     (c) Base

               It supports the bunsen burner.

     (d) Barrel

             Mix air with gas so as burning to take place on top.

7. (a) Different between Luminous flame and Non

luminous flame

-luminous flame is yellow in colour WHILE non-luminous flame is blue in colour

-luminous flame produces soot WHILE non-luminous flame does not Produce soot

-luminous flame produces less heat WHILE non-luminous flame produces more heat

-luminous flame has a wavy flame WHILE non-luminous flame has a triangular flame

-luminous burns quietly WHILE non-luminous flame burns with a roaring noise

-luminous flame has foul zone WHILE non-luminous flame has three zone.

    (b) Similarities between luminous flame and non-luminous flame.

  -both produce heat

  -both used in heating and cooking.

8. Substances that burn and produce luminous flame.

  -Plastics

  -Candle

  -Paper

  -Firewood

  -Clothes

  -Grass

9. (a) uses of flames.

    -used for heating

   -used for lighting

   -used for testing chemicals(flame test)

   -used for welding.

   -used for cooking.

 (b) activities that need non-luminous flame.

    -welding

   -flame test

   -heating

   -cooking

10. Characteristics of Luminous flame and Non luminous flame.

 (i) Luminous flame

-it is yellow in colour

-Produces soot

-Produces less heat

-Has a wavy flame

-Burns quietly

-has four zone (parts)

 (ii) Non-luminous flame.

 -is blue in colour

– Does not Produces soot

-Produce less more heat

-Has a triangular flame

-Burns with a roaring noise

-has three zone

11. Luminous flame is important because:-

• it helps to provide heat that used for different activities
• it helps to provide light during night

12. Inner zone. Because burning does not take place at that zone.

13. -Bunsen burner

       -Spirit burner

      -gas stove

      -kerosene burner (stove)

      -charcoal burner.

      -candle burner

14. Because it receives more air than other parts such that combustion at outer zone is effective, this results to production of more heat than other parts of the flame.particles at a high speed.

CHEMISTRY FORM ONE REVIEW

SCIENTIFIC PROCEDURE

QUESTIONS

1. Multiple choice

   Choose the correct answer from the alternative provided.

  (i) In ___________ scientific procedure applied during planning in order to get success or benefit in a certain activity.

  A: experiment  B: field study  C: project work  D: studying

 (ii) The step in scientific procedure before the last one is

  A: experimentation  B: data interpretation  C: data collection  D: conclusion

 (iii) Factors in an experiment that can be manipulated to get desired results

  A: controlled variables  B: independent variables

  C: dependent variables  D: manipulated variables

 (iv) __________ is a step at which observation happens.

 A: Experimentation  B: Hypothesis formulation

 C: Data recording   D: Problem identification

 (v) If the results you obtained from an experiment do not support your hypothesis ________________

 A: change your experiment   B: leave out the results

 C: identify new problem   D: give ideas for further testing to find a solution

2. Match items in list A with responses in list B

   List A

 (i) In field study

 (ii) Dependant variables

 (iii) Controlled variable

 (iv) In experiment

 (v) Independent variable

  List B

 A: scientific procedure applied by doing practical.

 B: is a factor in an experiment which does not change.

C: testing is involved so as to study and gain new knowledge

D: is a factor in an experiment that its value change with change of values of other variables.

E: the value in an experiment that manipulated so as to obtain different values for comparison.

3. Write T for correct statement and F for incorrect statement.

 (a) it is not wise to take medicine without medical test.

 (b) not all experiments aim to solve scientific problems

 (c) A suitable experiment must consider the factor that may affect the problem under investigation.

 (d) The scientific procedure is only used in project work

 (e) Hypothesis are true statement after long term experimentation.

4. (a) Mention advantages of scientific procedure.

    (b) List down application of scientific procedure

5. State the meaning(definitions) of the following

  (i) Scientific procedure  (ii) Hypothesis  (iii) Experimentation

  (iv) Observation  (v) Variables

6. Systematically, analyse steps involved in doing scientific investigation.
7. When do hypothesis rejected or accepted?
8. Mention the major problem that we normally account in our normal life and you think they can be solved by following scientific procedure.

9. What should be done when carrying out experiment and you find results that do not agree with the hypothesis?

      ANSWERS:

1. (i) C(ii) B    (iii) B    (iv) A   (v) D

2. (i) A(ii) D   (iii) B   (iv) C   (v) E

3. (i)T(ii) T   (iii) T   (iv) F   (v) F

4. (a) Advantage(significance) of the Scientific Procedure
5. It helps us to solve scientific problems
6. It helps us to gain new knowledge

iii. It helps us to conduct project work

iv.It helps us to carry out field study

  (b) Scientific procedure applied in:-

     (i) Carry out experiments.

            For studying and gaining new knowledge through testing.

   (ii) Project work.

             To plan by studying the project or problem so as to find useful information or solution for the project.

    (iii) Field study.

              To find answers for the problem by doing practical work.

5. (i) scientific procedure is a set of techniques used by scientists to investigate a problem/answer question.

   (ii) Hypothesis is an answer to the problem that may be true or false.

   (iii) Experimentation is practical activity aiming to get the solution of the problem.

   (iv) Observation is the process of detecting results of the experiment.

   (v) Variables are factors that affect the problem when conducting an experiment.

6.The following are steps followed when carrying out a scientific investigation

1. Identification of the Problem
2. Formulation of the hypothesis

iii. Experimentation and observation

1. Data collection and analysis
2. Data interpretation
3. conclusion from

7. Hypothesis may be rejected if it is disproved by experiment and accepted if it is proved by experiment.
8. -Diseases

    -Poor economic status

    -Bad examination results

    -Disasters (flood, drought etc)

9. If the result do not agree with the hypothesis, the following should be done.

    – Do not leave the experiment results you obtained.

   -Find possible reasons for difference between your hypothesis and experimental results.

   -Give ideas for further testing to find solution.

MATTER

QUESTIONS.

1. Multiple choice.

    Choose the most correct answer.

(i) The following conditions may affect the state of matter.

  A: pressure and colour       B: type of container

  C: pressure and temperature  D: volume and time

(ii) Applied to separate the mixture if the components of the mixture have different boiling points.

   A: decantation  method   B: layer separation method

   C: solvent extraction      D: fractional distillation

(iii) Matter exists in _________ physical states.

  A: two.    B: five.    C: three   D: four

(iv)Molecular particles in solid state of mater are closely packed together and _________ exists between them.

A: strong force of attraction   B: bond

C: weak force of attraction    D: gravity

(v) Gaseous substance in a container may change into _________ if pressure is increased.

  A: liquid  B: sublimes   C: solid  D: powdered

(vi) is a homogeneous mixture of two or more substances.

  A: solute  B: solvent  C: solution  D: suspension

(vii) One of the following is not matter.

  A: chalk  B: diesel  C: air  D: colour

(viii) in the following substance, its particles are arranged in a fixed pattern.

A: water   B: carbon dioxide   C: iron   D: petrol

(ix). Making blades from flour is a _________

A: combustion   B: chemical change   C: physical change    D: rusting

(x) For the substance which its particles are separated and they are free to move, it means that substance is ___________

  A: a gas  B: a solid  C: a liquid  D: wood

(xi) which of the following substances sublimes

A: iodine, aluminium chloride, ammonium chloride and anhydrous iron chloride

B: sand, plastics, sugar and salt

C: salt, sugar, glucose and ice

D: water, petrol, diesel and kerosene

(xii) ________ is a method which used to separate mixture of substances with different densities.

  A: chromatography  B: filtering  C: boiling  D: layer separation

(xiii) A substance that can be easily compressed in its containers is _______

A: stone  B: water   C: gas  D: grease

(xiv) Which of the following is a physical change?

A: turning sour of milk   B: salt dissolving in water

C: forest burning        D: fermentation of fruits

(xv) The following are uses of solvents except_________

A: cleaning   B: stain removal    C: breaching agent     D: greasing

(xvi) Syrups are examples of ______

   A: solutions  B: homogeneous mixture    C: suspension    D: filtrate

(xvii) In a sugar and water mixture, sugar is

A: solution   B: solvent   C: suspension   D: solute

(xviii) Decantation process involves

A: sedimentation   B: saturation   C: melting   D: distillation

(xix) The best way of separating iron filling from sulphur powder is by _________

A: separating funnel    B: evaporation   C: magnet    D: winnowing

(xx) When a small amount of salt is dissolved in a glass of water the mixture formed is _________

A:.heterogeneous   B: suspension   C: immiscible   D: homogeneous

2. Matching items.

   Match items in list A  with responses in list B

         List A

(i) Used to separate colour pigments.

(ii) The symbol of copper element

(iii) symbol for cobalt

(iv) Mixture of sand and iodine

(v) The group of metal elements

(vi) The mixture of flour and rice seeds

(vi) Examples of compounds

(vii) Examples of mixture

(viii) Mixture of maize and bean seeds

(ix) it is different from its constituent elements

(x) The group of non-metal elements

List B.

A: Can be separated by picking method

B: mud water and air(i) Used to separate colour pigments.

C: water and salts

D: K, Na and Mg

E: S, O and Ar

F: compound

G: sieving process can separate them

H: chromatography

I: sublimation method is used to separate them

J: Co

K: Cu

3. Name the following processes

   (a) Change of matter from liquid into solid

   (b) Change of matter from solid into liquid.

   (c) Direct change of matter from  solid into gas without passing through the liquid state.

   (d) Direct change of matter from gas into solid without passing through the liquid state.

   (e) Change of matter from gas into liquid.

   (f) Change of liquid matter into gas.

   (g) Structural change of matter

   (h) Composition change of matter

4. Classify the following

    (i) aluminium, silver, sulphur, copper, neon, calcium, chlorine and oxygen   into metals and non-metals

  (ii) ethanol, water, sugar, salt  into solute and solvent

   (iii) air, water, milk, ethanol, tea and crude oil into compound and mixture

5. Define the terms

   (a) Element   (b) Compound   (c) Mixture  (d) Solution   (e) Suspension

   (f) Solvent    (g) Solute       (h) Emulsion

6. Explain three types of solution.

7. Describe kinetic nature of matter in the following substances:-

  (a) iron   (b) lemon juice   (c) carbon dioxide

8. With examples, explain how mixture can be separated by using the following methods.

  (a) decantation  (b) sublimation  (c) filtration  (d) evaporation

  (e) fractional distillation  (f) chromatography  (g) solvent extraction

9. (a) Outline the characteristics of the following

   (i)liquid substances   (ii) gaseous substances   (iii) solid substances

   (iv) compound   (v) mixture

  (b) show difference between compound and mixture

  (c) is orange juice a mixture or a compound? Give two reasons

10.(i)  Name the methods which used to separate the following mixture.

   (a) mixture of water and petrol.

   (b) mixture of sand and water

   (c) mixture of water and ammonium chloride

   (d) mixture of ethanol and water

   (e) mixture of ammonium chloride and sand

  (ii) list steps necessary for the extraction of oil in groundnuts using ethanol as a solvent.

11. (i) Write the names of the elements represented by the following symbols.

  (a) Cu  (b) C  (c) Mg  (d) Na  (e) K  (f) S  (g) Cl

   (ii) Write the chemical symbols for the following elements

  (a) silicon  (b) lead  (c) iron  (d) fluorin

  (e) phosphorous

12. Explain the meaning of the following processes

(a) chemical change of matter  (b) physical change of matter

13. (a) What are the differences between

      (i) water and oxygen      (ii) kerosene and stone      (iii) oxygen and stone

  (b) with examples, name the states of matter

ANSWERS.

1. (i)C          (xi) A

    (ii) D          (xii) D

    (iii) C         (xiii) C

    (iv) A        (xiv) B

    (v)  A          (xv) D

   (vi)  C         (xvi) C

   (vii) D         (xvii) D

   (viii) C        (xviii) A

   (ix)   B          (xix) C

   (x)    A            (xx) D

2. (i) H(vi) C

    (ii) K          (vii) B

    (iii) J        (viii) A

    (iv)  I         (ix) F

     (v)  D         (x) E

3. (a) freezing

    (b) melting

   (c) sublimation

   (d) deposition (desublimation)

   (e) condensation

   (f) evaporation

   (g) physical change

   (h) chemical change

4. (i) metalsnon-metals

       -aluminium            -sulphur

       -silver                      -neon

       -copper                   -chlorine

       -calcium                 -oxygen

    (ii) Solute            Solvent

         -sugar            -ethanol

         -salt               -water

    (iii) compound             mixture

           -water.                  -air

          -ethanol.               -milk

          -tea                        -crude oil

5. (a) Element is a pure chemical substance which cannot be split into simpler substances by any chemical means.

     (b) Compound is a pure substance that obtained after chemical combination of two or more elements.

     (c) Mixture is a substance  which made up of two or more substance that not chemically combined together.

    (d) Solution is homogeneous mixture of two or more substances.

     (e) Suspension is heterogeneous mixture of two or more substances.

    (f) Solvent is a substance which dissolves other substances(solutes).

   (g) Solute is a substance which dissolved in another substance(solvent).

   (h) Emulsion is a mixture of liquids that do not mix completely with each other.

6. Types of Solutions

On the basis of dissolution of solute in solvent, solutions can be classified in three types;

  -saturated,

 -unsaturated and

 -supersaturated solutions.

An unsaturated solution can be defined as the solution in which solvent is capable of dissolving any more solute at given temperature.

 In other words, solvent does not contain enough amount of solute in it and can dissolve more solute.

  A saturated solution is the solution in which solvent is not capable of dissolving any more solute at given temperature.

A super saturated solution contains large amount of solute at that temperature and as temperature become reduced the extra solute crystallize quickly.

7. The following are kinetic nature of the substances

 (a) Iron, particles are closely packed in a regular arrangement. The particles vibrate about a fixed position.

(b) lemon juice, particles are closely packed in a random arrangement. The particles can move through the liquid but they cling together.

Carbon dioxide, The particles are far apart. There motion is random and independent of the other particles.

8. (a) decantation is a method which used to separate suspension components that take short time to settle down completely.

-solid portion of the mixture allowed to settle completely, then a clear liquid portion poured carefully into another container leaving the solid particles.

(b) Sublimation is method which used to separate mixture that contain component which sublimes.

  -the mixture heated to a certain temperature that make one of the component in a mixture to sublime as a pure component leaving residuals unchanged.

(c) filtration.

      Is a method which used to separate components of suspension that take long time to settle completely.

   -filter paper prepared and placed in a filter funnel then the mixture is powered carefully on a filter paper in a filter funnel. Clear liquid is obtained

  (d) evaporation is a method which used to separate solute from liquid solution.

   -A solvent is converted into gas when the mixture boiled/heated and solute remains as residue.

  (e) fractional distillation is a method that used to separate homogeneous mixture that its components differ in boiling points.

    -The component with lower boiling point escape  and collected first as pure substance.

  (f) chromatography is method of separating mixture of the colour pigments.

    -it separate colour pigments by determining rate of movement of coloured substances.

  (g) solvent extraction

         Is a method which used to separate oil from plants materials, especially seeds.

    -solvent is used to dissolve oil and the mixture of solvent and oil distilled so as to obtain pure oil.

9. (a) (i) Properties of Liquid Matter

-Particles are slight father apart

-Have definite volume

-Have not definite shape

-Have medium density due to medium

volume

– Have medium motion

– Inter-particle force is weak

   (ii) Properties of Gas Matter

-have not definite shape

-have not definite volume

-have largest inter particle distance

-have low density due to largest volume

-have weakest inter particle force

– Particles move at high speed

Change of State in Matter

  (iii) Properties of Solid Matter

– Particles are closely packed together

-Have definite shape and volume

-Have strongest inter-particle force

-Particles are not free to move

-Have high density

  (iv) Properties of compound

1. Compound cannot be seen separated
2. Constituent elements can be separated by chemical means

iii. Constituent elements Have definite ratio

iv.When formed involve chemical change

1. Its properties differ from its Constituent elements

  (v) properties of mixture

1. mixture can be seen separated
2. Constituent elements can be separated by physical means

iii. Constituent elements Have no definite ratio

iv.When formed involve physical change

1. It shows properties same as its Constituent elements

(b) difference between compound and mixture

(i) in a compound its components not seen separately while in a mixture components seen separately.

(ii) Components of a compound separated by chemical means while components of mixture separated by physical means.

(iii) energy is involved during formation of compound while when forming a mixture energy is not involved

(iv) there is definite ratio of component in a compound while in a mixture components combine in any ratio.

(v) formation of compound involves chemical change while in forming a mixture physical change is involved.

(c) Orange juice is a compound due to the following reasons

(i). Its Constituent elements Have definite ratio

(ii). Its properties differ from its Constituent elements

(iii) in an orange components not seen separately

a) Layer separation

b) Decantation

c) Sublimation

d) Fractional distillation

e) Sublimation

(ii) The entire extraction process can be divided into the following stages.

-Preparation of raw material

-Process of extraction

-Desolventization of extracted material

-Distillation of miscella

-Solvent recovery by absorption

-Meal finishing and bagging

(i) a) copper

b) carbon

c) magnesium

d) sodium

e) potassium

f) sulphur

g) chlorine

      (ii) a) Si

1. b) Pb
2. c) Fe
3. d) F
4. e) P

12. (a) Chemical change of matter

                   Refers to the change of matter which affects the chemical composition of matter.

     Changes involve breaking of bond and establishing new bonds.

   (b) physical change of matter

        Refers to the change of matter which does not affect the chemical composition of matter.

     Changes do not involve breaking of bond and establishing new bonds.

13. (a) (i) Difference between water and oxygen

        – in water Particles are slight father apart While in oxygen there is great inter particle distance

        -water has definite volume and no definite shape while oxygen has no both definite shape and volume.

       -water has week intermolecular force of attraction while oxygen has no intermolecular force of attraction

(ii) difference between kerosene and stone

     -particles in kerosene are not arranged in fixed pattern while in a stone particles are arranged in fixed pattern

        – in kerosene Particles are slight father apart While in stone are closer

        -kerosene has definite volume and no definite shape while stone has both definite shape and volume.

       -kerosene has week intermolecular force of attraction while stone has strong intermolecular force of attraction

  (iii) difference between oxygen and stone

     -particles in oxygen are free to move in either direction in its container While in a stone particles are fixed such that they are not free to move(they vibrate in their fixed positions)

   -oxygen has no definite volume and shape While stone has definite volume and shape.

  -in oxygen, there is no intermolecular force of attraction between particles While in a stone a strong intermolecular force of attraction exists between particles.

-in oxygen there is great distance from one particle and another while in a stone particles are closer.

  (b) We have three states of matter which are

  (i) Solid state  for example wood, iron and plastics

  (ii) Liquid state  for example water, petrol and soda

  (iii) Gaseous state for example carbon dioxide, oxygen and hydrogen

AIR,COMBUSTION,RUSTING AND FIRE FIGHTING.

   QUESTIONS.

1. Multiple choice.

   Choose the most correct answer.

  (i) What type of fire occurs in the vapour air-mixture over the surface of flammable liquids?

  A: class A

  B: class C

  C: class B

  D: class D

(ii) Combustion enables the following processes except _______

   A: washing

   B: heating

   C: smelting

   D: cooking

(iii)In order to start fire, the following components are needed

    A: fuel, oxygen and heat

    B: air and fuel

    C: heat and oxygen

    D: heat and combustible materials

(iv) Under normal condition, the percentage of oxygen in air is______

  A: 7.8       B: 21      C: 78           D: 2.1

(v) It is caused by combustible metals

   A: fire class A

   B: fire class B

   C: fire class C

   D: fire class D

(vi) A rapid chemical reaction that releases energy in form of light and noticeable heat is called __________

  A: ignition

  B: a reactant

  C: combustion

  D: heating

(vii) Occurs when combustible materials ignited and combine with oxygen.

  A: fire    B: heat     C: flame   D: soot

(viii) The process of extinguishing harmful fire

   A: fire starting

   B: fire outbreak

   C: fire fighting

   D: fire controlling

(ix) A portable fire extinguisher is always

    A: opened

    B: liquefied

    C: heavy

    D: in a metal container

(x) is formed on metal surface in presence of moisture and oxygen

  A: brown coating

  B: liquid

  C: soot

  D: red coating

2. Matching items

   Match items in list A with responses in list B.

     LIST A.

(i) Turning of lime water into milky.

(ii) Tin plating

(iii) Oiling

(iv) Galvanization

(v) Silca gel

(vi)

(vii) Plastics

(viii) The gas that makes iron or steel rust

(ix) Change of dry salt into hydrated when it is exposed to the air.

(x) Rusting

    LIST  B.

A: Carbon dioxide

B: Oxygen

C: Formation or brown coat on the metal surface

D: Indicates that water is contained in air.

E: Indicates that, air contains carbon dioxide

F: Iron is coated with tin.

G: Tin is mixed with iron

H: Coating metal  that do not get rust

J: Prevent rust by absorbing moisture

K: Less expensive and never rust.

L: Air and moisture prevented to the metal surface.

3. Fill in the blank spaces in the following statements.

(i) Iron,  _______and _______are necessary for rusting process.

(ii) Materials that catch fire and burn easily are said to be __________

(iii) The process of coating iron or steel with zink is known as _______

(iv) An APW fire extinguisher contains _______ pressurized by ____

(v) Combustion is a _________ process between substance and oxygen when flame is applied to them.

4. Explain the methods which used to prevent rust.
5. Why air is a mixture and not compound?
6. How can we test the presence of the following substances in air?

    (a) Water

    (b) Carbon dioxide.

    (c) Oxygen.

7. Define the following:-

    (a) Air

    (b) Combustion

    (c) Rusting

    (d) Rust

    (e) Fire

     (f) Fire fighting

8. Which substances( conditions) are needed in order thefollowing processes to take place?

    (a) Rusting

    (b) Combustion

9. Explain why water should not be used to extinguish fire class B and C?
10. (a) Explain classes of fire and suitable extinguisher per each class.

     (b) Mention the chemical composition of each fire extinguisher suggested in (a) above.

11. How rusting is prevented by:-

      (a) Oiling

      (b) Tin plating

      (c)  Painting

12. Describe application of combustion and its importance.
13. What should be done if fire caused by the following substances occur accidentaly.

   (a) clothes

   (b) petrol

   (c) electricity

   (d) cooking oil

14. Atuganile was preparing food for her family, using a hot oil in a frying pan. Accidentally , the pan tipped over and a huge fire spread on her kitchen floor.

  (a) Which extinguisher would be appropriate for putting out fire?

  (b) Which extinguisher would be dangerous to use so as to put out fire?

15. Outline components of air.

       ANSWERS.

1. (i) C(vi) C

   (ii)  A               (vii) A

   (iii) A              (viii) C

   (iv) B              (ix) D

   (v)  D              (x) A

3. (i) oxygen, water

   (ii) flammable

  (iii) galvanization

  (iv) air, water

   (v) burning

2. (i)E                (vi) _

   (ii)  F                (vii) K

   (iii)  L               (viii) B

   (iv) H                (ix) D

   (v) J                 (x) C

3. (i) oxygen, water

   (ii) flammable

   (iii) galvanization

   (iv) air, pressure

   (v) burning

4. The following methods applied to prevent rust

   (i) Painting

Paint when introduce on iron/steel prevent

iron/steel to react with water and air.

  (ii) Oiling

Oil when introduce on iron/steel prevent iron/steel to contact with water and air.

  (iii) Galvanization

  Galvanization is the process of mix iron/steel with metal that does not rusting.

When iron/steel mix with metal that does not rusting tend to prevent an iron/steel from rusting. Example Iron sheets are galvanized with zinc

   (iv) Anodizing

   Iron is joined to reactive metals (e.g. Magnesium) by wire. Examples

• Bridges are anodized to protect it from rusting
• pipelines are anodized to protect it from rusting

(v) Tin plating

    plating is the coating of iron/steel with tin (metal) that does not rust.

When iron/steel mix with metal that does not rusting tend to prevent an iron/steel from rusting.

   (vi) Use of silica gel

    silica gel is a substance in the form of grains and absorbs moisture.

Example

• silica gel bags put inside cameral parts which made from iron/steel to prevent rusting

Use of plastic

Uses of plastics tend to avoid cost of damage parts or instruments and household made from rusting.

5. Air is a mixture due to the following reasons

   (i) Air can be separated into its components like N2, O2 , Argon and CO2 by the process of fractional distillation of liquid air(physical means)

  (ii) It shows the properties of each  gas present in the atmosphere.

For example : Oxygen is good Supporter of combustion. Hence air also is good supporter of combustion.

   (iii) Air does not have a fixed formula.

   (iv) Air has a variable composition because air at different places contains different amount of gases.

   (v) Heat or Light energy is neither absorbed nor released when  air is prepared physically by mixing required amount of gases .

  (vi) Mixture does have fixed boiling Point like air. It holds good in case of liquid air.

6. (a) We can test the presence of water in air by exposing white anhydrous copper (II) sulphate. White copper two sulphate turns blue after absorbing atmospheric water.

   (b) We can test the presence of carbon dioxide in air by exposing lime water on the watch glass to the air. After few days lime water turns milky is carbon dioxide is contained in the air.

   (c) Copper is used to test if oxygen is present in air. If it is exposed to the air it turn black from brown to show that oxygen is present in air.

7. (a) Air

               Is a mixture of different gases.

     (b) Combustion

            Is a burning of the substance in presence of air (oxygen)

       (c) Rusting

              Is a process forming reddish brown coat on metals.

      (d) Rust

             Is a reddish brown coating on iron or steel caused by chemical reaction between iron(steel), water and oxygen.

      (e) Fire

           Is a collection of burning gases that give out heat and light.

    (f) Fire fighting

          is a process of extinguishing harmful fire

8. (a) Conditions needed for rusting process include presence of

     (i) iron or steel

     (ii) water(moisture)

     (iii) oxygen(air)

   (b) Conditions needed for combustion process include presence of:-

      (i) fuel (combustible materials)

      (ii) heat

      (iii) oxygen (air)

9. – Water should not be used to extinguish fire class B because it is denser than liquid fuel such that it sinks down and leave the oil burning at the top this causes spreading of the fire.

    -For the fire class C water creates a shock hazard.

10. (a) We have six classes of fire, which are fire class A, B, C, D, Eand F.

• Fire class A

      Is a type of fire caused by solid solid combustible materials such as wood, plastics and papers.

  -appropriate extinguisher for this type of fire is water and any portable extinguisher except carbon dioxide.

• Fire class B

    Is a type of fire caused by flammable liquids. Such as petrol, alcohol and kerosene.

  -it is extinguished by fire blanket if it is small and dry powder, foam or carbon dioxide if it is large.

• Fire class C

       Is a type of fire which caused by flammable gases. Such as butane and propane.

      -its extinguishers are dry powder extinguisher and carbon dioxide

• Fire class D

        Is a type of fire which caused by combustible metals. Such as magnesium, sodium and lithium usually when they are in powdered form.

    – appropriate extinguisher for this type of fire are dry powder extinguisher and foam extinguisher.

• Fire class E

     Is a type of fire which caused by electrical equipment.

     -it is extinguished by carbon dioxide or dry powder extinguisher.

• Fire class F

      Is a fire that caused by cooking appliances with oil and fat at high temperature.

   -it is extinguished by wet chemical extinguisher while the electric main power is switched off.

11. (a) Oil avoid rusting by preventing water and oxygen to the metal.

       (b) Tin is a metal which does not rust, if it is coated on iron or steel no rusting of iron or steel can take place.

       (c) Paints consist of material non-reactive metal(zinc). They avoid reaction between painted iron or steel against oxygen and water.

12. Application of combustion is described as follows.

• it is applied  in cooking

     Fuel burnt so as to get heat energy which is specific for cooking.

• it is applied in cleaning.

    It enables burning of wastes.

• it is applied in heating.

    Fuel burn burnt so as to produce energy which is specific for heating.

• it is applied in engine machines.

      Fuel is burnt so as to produce energy that run machine.

• it is applied in welding and smelting.

        Fuel is burnt to produce a very hot flame which is specific for welding and smelting.

• it is applied in lighting.

    Fuel is burnt to produce a flame which is specific for  giving light.

  NB:

     -fuel is any substance that when burn energy is produced usually in form of heat and light.

     -flame is a visible gaseous part of fire.

13. Immediately, fire should be put off by using appropriate extinguishers as follows:-

   (a) Fire caused by clothes is a fire class A. It should be extinguished by water.

   (b) Fire caused by petrol is fire class B. It should be extinguished by either fire blanket or sand if it is small, if it is large a dry powder, foam or carbon dioxide should be used.

  (c) Fire caused by electricity is a fire class E. It should be extinguished by carbon dioxide..

  (d) Fire caused by cooking oil is a fire class F. It should be extinguished by a wet chemical extinguisher.

14. (a) Wet chemical extinguisher

      (b) Water

15. Air is composed with the following.

     -carbon dioxide (0.03%)

     -oxygen (21%)

     -water vapour (0-4%)

     -nitrogen (78%)

     -noble gases (0.94)