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Chemical
equations
Francine
Taylor-Campbell, Contributor
 |
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THIS LESSON, WE INTEND TO LOOK AT WRITING AND BALANCING CHEMICAL EQUATIONS, AS
THIS TOPIC IS CRUCIAL IN UNDERSTANDING CHEMISTRY! First
of all, an equation is a representation of a reaction. An equation should show
the reactants and products taking part in a chemical reaction and should show
in what ratio these products combine. In
writing an equation, the first step is to express it in word form. This ensures
that all reactants and possible products are accounted for. The
second step is to express the word equation in symbols. Here, the correct formula
for each reactant and product must be given. The
final step is to check that the same number of atoms of a given element or their
ions are on each side. When this is done, the equation is said to be balanced.
State symbols are also added to the equation. Now
let us examine the following questions. 1.
Write an equation for the reaction between calcium oxide and water. Water
+ Calcium oxide  Calcium
hydroxide WORD H2O
(l) + CaO (s) Ca(OH)2
(aq) FORMULA Checking
the number of atoms of each element on both sides 2
H 2 H 2
O 2 O 1
Ca 1 Ca This
equation is BALANCED. 2.
Write an equation for the reaction between sodium carbonate and hydrochloric acid.
Sodium
carbonate + hydrochloric acid
sodium chloride + carbon dioxide + water Na2CO3
(s) + HCl (aq) NaCl
+ CO2 (g) + H2O (l) Checking
both sides 2
Na 1 Na 1
C 1 C 3
O 3 O 1
H 2 H 1
Cl 1 Cl To
balance this equation, 2 can be placed before the Na atom to have 2 Na atoms on
both sides. Na2CO3
(s) + HCl (aq) 2NaCl
+ CO2 (g) + H2O (l) This
means we now have 2 Cl on one side and 1 Cl on the other side. Placing a 2 before
HCl will balance this. Na2CO3
(s) + 2HCl (aq) 2NaCl
+ CO2 (g) + H2O (l) Balanced 3.
Write an equation, for the reaction between sodium hydroxide and phosphoric acid.
Sodium
hydroxide + phosphoric acid
sodium phosphate + water NaOH
(aq) + H3PO4 (aq)
Na3PO4 (aq) + H2O (l) Checking
sides 1
Na 3 Na 5
O 5 O 4
H 2 H 1
P 1 P Put
3 in front of NaOH to balance the Na 3NaOH
(aq) + H3PO4 (aq)
Na3PO4 (aq) + H2O (l) This
now creates 6 H 2
H which can be balanced by multiplying the 2 H by 3. 3NaOH
(aq) + H3PO4 (aq)
Na3PO4 (aq) + 3H2O (l) Balanced Francine
Taylor-Campbell is an independent contributor. | 
