C1 1.5 CHEMICAL EQUATIONS

· Chemical equations show the reactants (what we start with) and the products (what we

end up with)

· We often use symbol equations to make life easier

CaCO3 CaO + CO2 ·This is balanced same number of each type of atom

on both sides of the equation

Ca = 1 Ca = 1

C=1 C=1 ·We can check this by counting the number of each

O=3 O=3 type on either side

MAKING EQUATIONS BALANCE H2 + O2 H2O

H=2 H=2

O=2 O=1

Equations MUST balance

Add a 2 to the products side to make the oxygen

We can ONLY add BIG numbers to the front of balance

a substance

H2 + O2 2H2O

H=2 H=4

We can tell elements within a compound by BIG O=2 O=2

letters This has changed the number of hydrogen atoms

so we must now adjust the reactant side:

CaCO3 this is a compound made of 3 elements

(calcium, carbon and oxygen) 2H2 + O2 2H2O…read more

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