Chemical symbol equations

 

What are chemical symbol equations?

 

Symbol equations are a quick way of representing chemical reactions. They show us the atoms and bonds of each substance and how they change in the reaction.  Symbol equations always take the format, reactants → products. A plus sign (+) is used to separate two or more reactants or products.

 

Writing symbol equations

Symbol equations use the symbols and formulae of the substances that are involved in chemical reactions. They show us what substances react and what substances are formed.

The reactants are the substances that react together. They are written first in a symbol equation, using their symbols or formulae. A plus sign (+) is used to separate two or more reactants.

An arrow (→) is used after the reactants to show that a chemical reaction has occurred.

The products are the substances that are formed in the reaction. They are written after the arrow, using their symbols or formulae. A plus sign (+) is used to separate two or more products.

 

Example

When carbon (C) is burned, the carbon reacts with oxygen (O2) and carbon dioxide (CO2) is produced.

The symbol equation for this reaction is:

C + O2 → CO2

 

Compare this to the word equation:

Carbon + oxygen → carbon dioxide

 

🧪 Knowledge Check: Chemical Symbol Equations

Test your understanding of reactants, products, and how to read chemical formulas.

1. On which side of a chemical equation are the 'Reactants' always found?

• The right-hand side
• The left-hand side
• Above the arrow

2. What does the state symbol (s) represent when placed after a chemical formula?

• Solution
• Solid
• Steam

3. In a symbol equation, what does the arrow (→) stand for?

• Equals
• React to form
• Plus

4. Which state symbol is used for a substance that has been dissolved in water?

• (l)
• (g)
• (aq)

5. Why is a symbol equation often more useful than a word equation?

• It uses shorter names for chemicals.
• It shows the ratio of atoms and elements involved.
• It is easier to read for people who don't speak English.

Click to Reveal Answers

1. The left-hand side (Reactants go in, products come out).
2. Solid (Common state symbols include s, l, g, and aq).
3. React to form (It shows the direction of the reaction).
4. (aq) (Stands for aqueous).
5. Shows ratio of atoms/elements (Provides specific chemical details that words cannot).

 

Summary:

 

• Chemical reactions can be represented by symbol equations, which use the symbols and formulae of the substances involved.
• Symbol equations show us the atoms and bonds of each substance and how they change in the reaction.
• Symbol equations have the format, reactants → products. A plus sign (+) is used to separate two or more reactants or products.
• Symbol equations also use state symbols to indicate the physical state of each substance, whether it is a solid, liquid, gas or solution.