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Worksheets

Chemical Reactions

Total questions: 19

Worksheet time: 2hrs 31mins

Name
Class
Date
1.

Which of the following are signs of a chemical reaction?

a)

Formation of a gas

b)

A change in temperature

c)

A change in color

d)

A change in size

2.

In a chemical reaction, the number of atoms in the reactants and the products...

a)

Must be the same

b)

Must be different

3.

What is the density of water?

a)

1g/mL

b)

3g/mL

c)

7g/mL

d)

2.3g/mL

4.

Which of these is NOT a sign of a chemical reaction?

a)

A phase change

b)

Formation of a precipitate

c)

A color change

d)

A temperature change

5.

When a chemical reaction occurs...

a)

New molecules and atoms are formed

b)

Molecules and atoms are rearranged

c)

Molecules and atoms disappear

d)

Molecules and atoms are destroyed

6.

Is the chemical equation here balanced?

a)

Yes

b)

No

7.

Imagine you have an unknown substance in your hand. You know that it has a mass of 100g and a volume of 10cm3. What is the density of this unknown substance?

a)

5g/cm3

b)

11g/cm3

c)

10g/cm3

d)

25g/cm3

8.

In a cup you have 50g of water. This means you have how many mL's of water?

Remember: water has a density of 1g/mL.

a)

10mL

b)

74mL

c)

100mL

d)

50mL

9.

A pure substance is made of how many different types of atoms/molecules?

a)

4

b)

3

c)

1

d)

2

10.

A mixture is made of at least how many different types of atoms/molecules?

a)

2

b)

1

c)

4

d)

7

11.

You have 2 chemicals, CHEMICAL A and CHEMICAL B. They are both liquids. When you combine them you notice some crystals starting to form within them. Did a chemical reaction occur?

a)

Yes

b)

No

12.

You have a large glass of water and you stir salt into it until all the salt completely dissolves. Is this a chemical reaction?

a)

Yes

b)

No

13.

How is a pure substance different than a mixture?

4 lines
14.

Explain the law of conservation of mass is your own words.

4 lines
15.

This is the decomposition reaction of hydrogen peroxide. According to the law of conservation of mass, if you start with 40g of hydrogen peroxide you should end up with _____g of water and oxygen combined.

a)

10

b)

20

c)

30

d)

40

16.

When you combine baking soda and vinegar the reaction produces bubbles. Explain how you know that this is a chemical reaction.

4 lines
17.

You have a beaker full of water. If you add a solid substance to the beaker and the water level rises, is this a chemical reaction? Why or why not?

a)

Yes because it is a mixture now.

b)

No because there was no sign of a chemical reaction.

c)

Yes because the water moved.

d)

No because the temperature changed.

18.

Your pet rock has a density of 150g/cm3. You know it has a volume of 5cm3. What is its mass?

a)

800g

b)

750g

c)

5g

d)

1,000g

19.

Your dog has a mass of 2,000g and a volume of 500cm3. What is your dog's density?

a)

1g/cm3

b)

5g/cm3

c)

12g/cm3

d)

4g/cm3