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Writing a balanced Chemical Equation




In this lesson, we will learn how to write a balanced chemical equation given a word equations. We have more lessons on the rules for balancing chemical equations.

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More Chemistry Lessons

Chemical Equation

A chemical equation shows the overall change of reactants to products in a chemical reaction.


Sometimes, state symbols are required to indicate the physical states of the substances in a chemical reaction.

Physical state

State symbol

Solid

s

Liquid

l

Gas

g

Aqueous Solution

aq

Here are some simple covalent formulas that you will find useful to remember
Water H2O
Carbon Dioxide CO2
Ammonia NH3
Hydrogen H2
Oxygen O2
Nitrogen N2
Sulfur Dioxide or Sulphur Dioxide SO2
Methane CH4

Here are some simple ionic formulas that you will find useful to remember
Sodium Chloride NaCl
Calcium Chloride CaCl2
Magnesium Oxide MgO
Hydrochloric Acid HCl
Sulfuric Acid or Sulphuric Acid H2SO4
Nitric Acid HNO3
Sodium Hydroxide NaOH
Potassium Hydroxide KOH
Calcium Hydroxide Ca(OH)2
Calcium Carbonate CaCO3
Aluminum Oxide Al2O3
Iron Oxide Fe2O3

Conversion of word equation to chemical equation

Example:

In a precipitation reaction, sodium hydroxide solution is mixed with iron(II) chloride solution. Sodium Chloride solution and insoluble iron(II) hydroxide are produced. Write a balanced chemical equation including the state symbols.

Solution:

Step 1: Identify reactants and products and place them in a word equation,

sodium hydroxide + iron(II) chloride → sodium chloride + iron(II) hydroxide

Step 2: Convert the chemical names into chemical formulas. Place them based on the chemical equation and write the state symbols.

Step 3: Balance the chemical equation.

2NaOH(aq) + FeCl2(aq) → 2NaCl(aq) + Fe(OH)2(s)

Example:

Write a balanced chemical equation for

Sodium(s) + hydrochloric acid(aq) → sodium chloride(aq) + hydrogen(g)

Solution:

Step 1: Convert the chemical names into chemical formulas. Place them based on the chemical equation and write the state symbols.

Step 2: Balance the chemical equation.

2Na(s) + 2HCl(aq) → 2NaCl(aq) + H2(g)


 



Videos

How to write a chemical equation from a word equation and vice versa.
When compounds react, they are chemically changed into new compounds. Every chemical change can be communicated symbolically using a chemical equation. Chemical equations combine formulas with other symbols to show what changes takes place.

How to interpret chemical symbols and how to write simple balanced equations.

Writing Chemical Equations



Practice with writing and balancing equations


 



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