Download Balancing Chemical Equations - Mr. Gates` Chemistry website

Mr. Anthony Gates
Chemistry 101

Chemical Equations:
◦ The symbolic representation of a chemical reaction.
◦ Skeleton Equations:
 Chemical equation that tells us what is
involved, but not the relative amounts.
◦ Balanced Equation:
 Chemical equation that tells us what is
involved, and the relative amounts.

Skeleton:
◦ 𝐹𝑒 𝑠 + 𝑂2 𝑔 → 𝐹𝑒2 𝑂3 𝑠

Balanced:
◦ 4𝐹𝑒 𝑠 + 3𝑂2 𝑔 → 2𝐹𝑒2 𝑂3 𝑠

Parts:
◦ Reactants= substances present at the beginning of,
and involved in a chemical reaction.
◦ Products= substances created from a chemical
reaction.
◦ Coefficients= numbers used to show the amount of
a substance used in a chemical reaction as it is
related to other substances in the reaction.
1.
First write a skeleton equation
2.
Make a list of each element on each side and write
the number of atoms you have for each element.
3.
Change one of the coefficients to balance the
equation for a particular element.
4.
Repeat for another element
5.
◦ Constant guess and check
◦ Typically do Oxygen and Hydrogen last
Make sure all of the coefficients are the smallest
whole number ratios that balance the equation.

____𝐿𝑖2 𝑂 + ____𝐻2 𝑂 → ____𝐿𝑖𝑂𝐻

Reactants:
◦ 2 Li
◦ 2O
◦ 2H

Products:
◦ 1 Li
◦ 1O
◦ 1H

𝐿𝑖2 𝑂 + 𝐻2 𝑂 → 2 𝐿𝑖𝑂𝐻

Reactants:
◦ 2 Li
◦ 2O
◦ 2H

Products:
◦ 2 Li
◦ 2O
◦ 2H



____𝑁𝑎2 𝐻𝑃𝑂4 → ____𝑁𝑎4 𝑃2 𝑂7 + ____𝐻2 𝑂
Reactants:
◦
◦
◦
◦
2
1
4
1
Na
P
O
H
◦
◦
◦
◦
4
2
8
2
Na
P
O
H
Products:



2 𝑁𝑎2 𝐻𝑃𝑂4 → 𝑁𝑎4 𝑃2 𝑂7 + 𝐻2 𝑂
Reactants:
◦
◦
◦
◦
4
2
8
2
Na
P
O
H
◦
◦
◦
◦
4
2
8
2
Na
P
O
H
Products:

__𝑀𝑔𝑁𝐻4 𝑃𝑂4 → __𝑀𝑔2 𝑃2 𝑂7 + __𝑁𝐻3 + __𝐻2 𝑂

Reactants:

Products:
◦
◦
◦
◦
◦
1
1
1
4
4
Mg
N
P
H
O
◦
◦
◦
◦
◦
2
1
2
5
8
Mg
N
P
H
O

2 𝑀𝑔𝑁𝐻4 𝑃𝑂4 → __𝑀𝑔2 𝑃2 𝑂7 + __𝑁𝐻3 + __𝐻2 𝑂

Reactants:

Products:
◦
◦
◦
◦
◦
2
2
2
8
8
Mg
N
P
H
O
◦
◦
◦
◦
◦
2
1
2
5
8
Mg
N
P
H
O

2 𝑀𝑔𝑁𝐻4 𝑃𝑂4 → 𝑀𝑔2 𝑃2 𝑂7 + 2 𝑁𝐻3 + 𝐻2 𝑂

Reactants:

Products:
◦
◦
◦
◦
◦
2
2
2
8
8
Mg
N
P
H
O
◦
◦
◦
◦
◦
2
2
2
8
8
Mg
N
P
H
O
How do we go about
balancing a chemical
equation?
Talk with the person next to
you and discuss strategies.

(s)


(g)

(l)



(aq)
Symbol

Reactant/product is a
solid
Reactant/product is a
gas
Reactant/product is a
liquid
Reactant/product is in
an aqueous solution
(solid dissolved in
water)
What it means

Skeleton:
◦ 𝐹𝑒 𝑠 + 𝑂2 𝑔 → 𝐹𝑒2 𝑂3 𝑠

Balanced:
◦ 4𝐹𝑒 𝑠 + 3𝑂2 𝑔 → 2𝐹𝑒2 𝑂3 𝑠

∆
→
𝑃𝑡


→


+

Symbol
Heat is added to the
reaction
A catalyst is added to
the reaction
Separates two
reactants or two
products in the
equation.
What it means