What are reactions?

• Chemistry
• Lower Secondary (Key Stage 3)

What are reactions?

Name the reactant(s):

1. Nitrogen
2. Hydrogen
3. Nitrogen + Hydrogen
4. Ammonia

Sodium hydroxide is a...

1. Reactant
2. Product
3. None of the above
4. Element

How many products are there?

1. 1
2. 2
3. 3
4. 0

Water is a....

1. Reactant
2. Product

Lithium nitrate is a...

1. Reactant
2. Product

How many products are there?

1. 1
2. 2
3. 3
4. 4

Which reaction(s) have 2 reactants and 2 products?

Which reaction(s) makes 1 product from 2 reactants?

Write the chemical equation for the reaction of hydrogen and oxygen which produces water.

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Hydrogen

Oxygen

Water

Sam mixed together some eggs, milk and flour. When he heated them in a large pan they reacted to form a big pancake!

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Eggs

Milk

Flour

Pancake

When Katerina dropped a lump of magnesium into a test tube of hydrochloric acid, the chemical magnesium chloride was formed. Katerina also noticed hydrogen gas being formed.

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Magnesium

Hydrochloric acid

Magnesium chloride

Hydrogen

Shona was learning about photosynthesis. She looked on the internet and found that in this process, plants take in carbon dioxide gas from the air and water from the ground. Using energy from the sun they can turn these chemicals into a kind of sugar called glucose and the gas oxygen.

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Oxygen

Carbon dioxide

Water

Glucose

Your turn: In your book, write the word equation for each reaction.

1. A reaction between sulfur and oxygen occurs to form sulfur dioxide.

2. When you burn magnesium in the presence of oxygen gas you form magnesium oxide. 

3. Table salt (sodium chloride) and water are the products of a reaction between hydrochloric acid and sodium hydroxide.