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16 SCIPAD - BIG IDEAS - BOOK 2
NATURE OF THE ATOM
Chemical Word Equations
Chemical reactions (in which a chemical change occurs) can be represented by chemical word
equations.
•
The substances that are reacting together are called the reactants.
•
The substance or substances produced are called the products.
•
An arrow shows the direction of the reaction.
Reactant + reactant product(s)
For example, if sodium reacts with chlorine to form sodium chloride, we would write the word
equation as:
Sodium + chlorine sodium chloride
1. In the reaction above, what is the name of:
(a) the product? 
(b) the reactants? 
2. What does the arrow mean in a word equation? 

3. What happens to the sodium and the chlorine atoms? Where do they go? 

4. Write the following reactions as word equations. Remember to use ‘+’ instead of ‘reacts
with’ or ‘and’. Also remember to use an arrow to show the direction of the chemical
change.
(a) Hydrogen reacts with oxygen to form water.
		
(b) Magnesium and hydrochloric acid react to form magnesium chloride and
hydrogen.
		
(c) Copper oxide reacts with carbon to form copper and carbon dioxide.
		
(d) Methane reacts with oxygen to form water and carbon dioxide.
		
(e) Iron reacts with oxygen to form iron oxide.
		
(f) Calcium carbonate decomposes to form calcium oxide and carbon dioxide.
		
(g) Carbon burns in oxygen to form carbon dioxide.
		
(h) Zinc reacts with sulfuric acid to form zinc sulfate and hydrogen gas.
		
(i) Lead forms lead oxide when it reacts with oxygen.
		
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