Chemistry Grade 8 First Term Examination Portion Coverage, Answer Key and Work Sheet 2021

Chemistry Grade 8 First Term Examination Portion Coverage, Answer Key & Work Sheet 2021

Portion Coverage:

Chapter 15

Energy Changes (complete)

Exercise Page 201

a)     Oxygen

b)     water; combustion; monoxide; soot;            incomplete

c)     energy; increases; Endothermic;                  decreases

Question 1

Chapter 16

Rate of Reaction (complete)

Exercise Page 218

Question 1

                  a)     large;  larger;

        b)     faster; volume; collide

        c)     higher; quickly; more; harder

        d)     catalyst; unchanged

        e)     enzyme

Work Sheet

True and Falls.

• Exothermic reactions give out energy. T
• Endothermic reactions take in energy. T
• In exothermic reactions, the temperature goes down. F
• ΔH is negative for an endothermic reaction. F
• Breaking bonds requires energy. T
• Whenever chemicals react, we get a transfer of energy. T
• Food is the fuel for our bodies. T

Choose the Best.

1. You need 3 things to make a fire

a)Fuel  b)heat  c)oxygen

d)All of them

2. Fuels store ------------ energy.

a)P.E   b)K.E   d)none of them

c)Chemical

3. The gas we burn in a Bunsen burner is usually methan

a)CH      b)CH₂      c)CH₃

d)CH₄

4. Therefore we use a copper beaker (called a---------)

a)Thermometer   c)pH meter   d)barometer

b)Calorimeter

5. Some reactions take in heat from their surroundings. These are called ----------------------reactions.

b)Exothermic            c)both         d)none of them

a)endothermic

Fill in the Blanks.

The ---------------- the surface area, the faster the reaction. Large     

The more concentrated a solution is, the ----------------- it reacts. Faster

The --------------------  the temperature, the faster the reaction. Higher

A -------------------  is a substance which speeds up a reaction. Catalyst

An ---------------------- is a catalyst found in living things. Enzyme

Choose the Best.

 ---------------------flame shows complete combustion

B  yellow   c  both   d none of them

A blue

Rise in temperature is an example of ---------------

A endothermic   c both  d none of them

B Exothermic

Breaking bond required energy. It is -------------

B Exothermic   c both  d none of them

A endothermic   

The steeper the slope, the -------------------- reaction.

A   slow     c  both           d  none of them

B fast

As we increase the surface area, the rate of reaction -------.

A same   b decrease      d both b & c

C increase 

Reactants will convert into products if collision---------------

A    Unsuccessful      b normal       c   moderate       

D  Successful or effective 

In reactions between gases, increasing the pressure, increases the ----------- of reaction.

B  amount    c  time    d   temperature 

A rate

A catalyst is a substance which speeds up a chemical reaction. At the end of the reaction, the catalyst is chemically------------------------.

B Changed   c both  d  none of them 

A  unchanged

Enzymes are biological  -------------------.

A reactant    b  product    c   both B & D

D catalysts