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Chemical Reactions

Total questions: 45

Worksheet time: 23mins

Name
Class
Date
1.

True or false? Chemical reactions are easily reversible

a)

True

b)

False

2.

True or false: A change in state is a chemical reaction

a)

True - something melting would be an example of a chemical reaction

b)

False - a change in state is a physical change

3.

In a word equation, the starting chemicals are called...

a)

reactants

b)

products

c)

ingredients

4.

In this chemical reaction, which is the product/s?

Magnesium + Oxygen --> Magnesium oxide

a)

magnesium

b)

magnesium and oxygen

c)

magnesium oxide

d)

oxygen

5.

A material that burns to transfer energy is called a...

a)

compound

b)

wood

c)

fuel

d)

petrol

6.

What is the scientific term given when something burns?

a)

a fuel

b)

flammable

c)

combustion

d)

heating

7.

What does a fuel need in order to burn?

a)

fuel

b)

electricity

c)

oxygen

d)

hydrogen

8.

Sometimes, compounds can be broken down into simpler substances. What type of reaction is this?

a)

combustion

b)

oxidation

c)

decomposition

d)

displacement

9.

What is the correct equation for combustion?

a)

Hydrocarbon + carbon dioxide →\rightarrow water + energy

b)

Hydrocarbon + Oxygen →\rightarrow carbon dioxide + water ( + energy)

c)

Energy + oxygen →\rightarrow Carbon dioxide + water

d)

Hydrocarbon + water →\rightarrow Oxygen + energy

10.
Which of the following is evidence that a chemical change has taken place? 
a)
change in color
b)
change in size
c)
change in shape
d)
change in energy
11.
What is changed in a chemical reaction like this one? 
NaOH + HCl   →  NaCl + H2O
a)
the number of atoms is changed
b)
molecules and compounds are changed 
c)
atoms are changed
d)
elements are changed 
12.

Which of the following is NOT a sign of a chemical change

a)

Change in state

b)

Change in colour

c)

Change in temperature

d)

Fizzing and bubbling

13.

Chemical reactions transfer:

a)

Information

b)

Energy

c)

Molecules

d)

Gases

14.

In a chemical reaction:

a)

Some atoms are lost

b)

New molecules are produced

c)

Heat is always produced

d)

There is always an explosion

15.

A CATALYST is a substance :

a)

That reacts with oxygen to produce energy

b)

That slows down a chemical reaction

c)

That speeds up a chemical reaction

d)

That changes colour in a chemical reaction

16.

Which of these is a chemical reaction?

a)

Baking a cake

b)

Melting an ice cube

c)

Boiling a beaker of water

d)

Burning wood

e)

Dissolving sugar in a cup of tea

17.

Complete this word equation:
Iron + sulfur →\rightarrow  _____________

a)

Sulfur Iodide

b)

Iron oxide

c)

Iron Sulfide

d)

Iron sulfur

18.

Complete this word equation:
Magnesium+ Oxygen →\rightarrow  ____________

a)

Magnesium Oxygen

b)

Magnesium Oxide

c)

Oxygen Magnesium

d)

Oxide Magnesium

19.

Complete this word equation:
Iron +  __________ →\rightarrow  Sodium Chloride

a)

Chloride

b)

Chlorine

c)

Chlorate

d)

Chlorazine

20.

Complete this word equation
Lithium + Bomine →\rightarrow  ____________

a)

Lithium Bromate

b)

Lithium Bromide

c)

Lithium Bromazine

d)

Lithium Broxide

21.

The products of a chemical reaction always...

a)

Have the same colour as the reactants

b)

Have different chemical properties as the reactants

c)

Have a different weight than the reactants

d)

Have the same temperature as the reactants

22.

How many chemical reactions are taking place in this picture?

a)

1

b)

2

c)

3

d)

4

23.

What are the elements involved in the chemical reaction of rusting

a)

Metal and oxygen

b)

Iron and gas

c)

Iron and oxygen

d)

Metal and gas

24.

When iron reacts with oxygen in the air it produces

a)

Iron Oxygen

b)

Oxygen Ironide

c)

Iron Oxide

d)

Oxide Iron

25.

Which of these is a Physical change?

a)

Iron going rusty

b)

Frying an egg

c)

Melting chocolate

d)

Baking a cake

26.

How many Nitrogen (N) atoms are in 4NH3?

a)

4

b)

1

c)

3

d)

12

27.

How many Hydrogen (H) atoms are in 4NH3?

a)

4

b)

1

c)

3

d)

12

28.

How many total molecules is 4NH3?

a)

4

b)

1

c)

3

d)

12

29.

How many total atoms make up 4NH3?

a)

4

b)

16

c)

3

d)

12

30.

In the equation shown, what are the reactant(s)?

a)

N2 + H2

b)

NH3

31.

In the equation shown, what are the product(s)?

a)

N2 + H2

b)

NH3

32.

Is this equation balanced?

a)

Yes

b)

No

33.

Is this equation balanced?

a)

Yes

b)

No

34.

Is this equation balanced?

a)

Yes

b)

No

35.

Which reactant is missing from the equation shown?

(What should go in the place of the "X"?)

a)

One hydrogen atom.

b)

Three hydrogen atoms.

c)

Four oxygen atoms.

36.

Which of the following is a chemical reaction?

a)

Sodium and chlorine atoms bond to form salt molecules.

b)

Ice melts to form water.

c)

Carbon dioxide freezes to form dry ice.

d)

Salt and water mix to form salt water.

37.
When dry ice (solid carbon dioxide) sublimes it goes directly from a solid to a gas. What type of change is occurring? 
a)
Chemical change
b)
Physical change
c)
None of the above 
38.
Why must we balance chemical equations? 
a)
Our teacher said so
b)
to abide by the law of conservation of energy
c)
to abide by the law of conservation of mass
39.
What is changed in a chemical reaction like this one? 
NaOH + HCl   →  NaCl + H2O
a)
the number of atoms is changed
b)
molecules and compounds are changed 
c)
atoms are changed
d)
elements are changed 
40.

A material that burns to transfer energy is called a...

a)

compound

b)

wood

c)

fuel

d)

petrol

41.

What is the scientific term given when something burns?

a)

a fuel

b)

flammable

c)

combustion

d)

heating

42.

What does a fuel need in order to burn?

a)

fuel

b)

electricity

c)

oxygen

d)

hydrogen

43.

Sometimes, compounds can be broken down into simpler substances. What type of reaction is this?

a)

combustion

b)

oxidation

c)

decomposition

d)

displacement

44.

In the thermal decomposition of calcium carbonate:

Calcium carbonate --> Calcium oxide + ?

HINT: gas

a)

oxygen

b)

calcium

c)

carbon monoxide

d)

carbon dioxide

45.

What is the conservation of mass?

a)

mass of reactants > mass of products

b)

mass of reactants < mass of products

c)

mass of reactants = mass of products

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