UNDERSTAND CHEMICAL EQUATIONS

Question 1

Chemical reactions involve the creation of one or more new substances called products.
Normally, you can tell when a chemical reaction has occurred. Signs include a _________, a ___________, ___________ and/or ______________.

Answer 1

1. colour change
2. gas being given off
3. heat being released
4. a solid forming

Question 2

Word equations are used in chemistry to show the things that react, called ________, and the new substances produced, which are called ________.

Answer 2

1. reactant
2. products

Question 3

Often, when a metal reacts with oxygen, a ____________ is produced. For example, if magnesium metal is burned in oxygen, _____________ is produced. This is known as an ______________. This can be represented as a word equation: ???

Answer 3

1. metal oxide
2. magnesium oxide
3. oxidation reaction
4. Magnesium + Oxygen -> Magnesium oxide

Question 4

Most chemical reactions are ____________. This means that once the reaction has taken place it is very __________ to get the reactants back. We can’t reverse it.

Answer 4

1. irreversible
2. difficult

Question 5

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

Answer 5

Products

Question 6

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

Answer 6

Reactants

Question 7

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.

1. What are the reactants?
2. What are the products?

Answer 7

1. Sodium and water
2. Sodium hydroxide and hydrogen

Question 8

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.

1. What are the reactants?
2. What are the products?

Answer 8

1. Magnesium and hydrochloric acid
2. Hydrogen and magnesium chloride

Question 9

A + oxygen -> magnesium oxide
sodium + oxygen -> B
calcium + C -> calcium oxide

1. What is chemical A?
2. What is chemical B?
3. What is chemical C?

Answer 9

1. magnesium
2. sodium oxide
3. oxygen