Chemical Equations Worksheet

Chemical reactions happen every day:

Car from the burning of petrol in car engine...

Rust ...to the rusting of iron.

There are millions of reactions taking place every second of every day.

Chemical reactions involve the production of one or more new substances called products. Word equations are used in chemistry to show the things that react, called reactants, and the new substances produced, which are called products.

Reactants Products

For example, if magnesium metal is burned in oxygen, magnesium oxide is produced. This can be represented as a word equation:

Magnesium + Oxygen Magnesium oxide

Word equations like these are used a lot in science as a quick way of representing a chemical reaction.

Most chemical reactions are irreversible. This means that once the reaction has taken place it is very difficult to get the reactants back.

Think how difficult it would be to turn the fumes from the exhaust pipe of a car back into petrol!

What name is given to the new substances produced by a chemical reaction?

Reactants

Products

Chemicals

What name is given to the substances that combine during a chemical reaction to form one or more new substances?

Reactants

Products

Chemicals

Read this description of an experiment carefully:

A scientist places some sodium metal in water and stands back. Quickly she observes lots of smoke and flames being produced. Once the experiment is complete, tests show that both the compound sodium hydroxide and hydrogen gas were produced by the reaction.

Use this information to complete the table below.

Read this description of an experiment carefully:

Some magnesium metal is placed into a test tube of hydrochloric acid and immediately bubbles of hydrogen gas can be seen and the test tube begins to heat up. Magnesium chloride is also produced in this reaction.

Use this information to complete the table below.

Use the table below to complete these word equations.

Enter your answers in lower case.

A + Oxygen Magnesium oxide

Sodium + Oxygen B

Calcium + C Calcium oxide

	Answer
A
B
C

ANSWERS

Question 1

What name is given to the new substances produced by a chemical reaction?

CORRECT ANSWER

Products

EDDIE SAYS

A chemical reaction involves the combining of reactants to form one or more new substances called products.

ANSWERS

Question 2

What name is given to the substances that combine during a chemical reaction to form one or more new substances?

CORRECT ANSWER

Reactants

EDDIE SAYS

A chemical reaction involves the combining of reactants to form one or more new substances called products.

ANSWERS

ANSWERS

Question 4

Read this description of an experiment carefully:

A scientist places some sodium metal in water and stands back. Quickly she observes lots of smoke and flames being produced. Once the experiment is complete, tests show that both the compound sodium hydroxide and hydrogen gas were produced by the reaction.

Use this information to complete the table below.

EDDIE SAYS

Descriptions of experiments must be read carefully to identify both the reactants and the products. Remember, only the chemicals involved in the reaction are included. Fire, for example, is not a chemical - it is, in fact, a form of energy, so is not included in equations.

ANSWERS

Question 5

Read this description of an experiment carefully:

Some magnesium metal is placed into a test tube of hydrochloric acid and immediately bubbles of hydrogen gas can be seen and the test tube begins to heat up. Magnesium chloride is also produced in this reaction.

Use this information to complete the table below.

EDDIE SAYS

Remember only the chemicals involved in the reaction are included. Here, the description shows that the reactants are magnesium and hydrochloric acid, as they are combined at the start of the experiment. It goes on to show that the products are hydrogen and magnesium chloride.

ANSWERS

Question 6

Use the table below to complete these word equations.

Enter your answers in lower case.

A + Oxygen Magnesium oxide

Sodium + Oxygen B

Calcium + C Calcium oxide

CORRECT ANSWER

	Answer
A
B
C

EDDIE SAYS

Can you see what's going on? In the first one, the product is magnesium oxide, so it must be magnesium that's reacted with the oxygen. You see, each equation gives you a clue to the answer of the other equations.

ANSWERS

Question 7

Complete the table below to show which changes are chemical reactions and which are not.

EDDIE SAYS

The best way to identify a chemical reaction is to think about how easy it would be to reverse the change, for example you can turn steam back into water so it is unlikely to be a chemical reaction but you can't unfry an egg so this is a chemical reaction.