1. MRS. MARY GRACE B. ANTICUANDO
Write and balanced chemical equations
2. Guidelines for writing and
balancing chemical equations:
1. Determine the correct chemical
formulas for each reactant and product.
Scientific findings 2
Cu Ag
AgNO₃ Cu(NO₃)₂
2. Write the skeleton equation. Cu+AgNO₃ Cu(NO₃)₂+ Ag
3. Count the number of atoms of each element that appears
as a reactant and as a product. If a polyatomic ion is
unchanged on both sides of the equation, count it as a unit.
3. Guidelines for writing and balancing chemical equations:
4. Balance each element on at a time by placing coefficients in
front of the formulas. A coefficient is a small whole number
placed in front of a formula in an equation in order to balance it.
Scientific findings 3
Cu + AgNO₃
a. It is best to begin by balancing elements that only appear in one
formula on each side of the equation
b. If the coefficient is 1; no need to indicate.
c. Never change the subscripts in a chemical formula, you can
only balance equations by using coefficients.
Cu(NO₃)₂ + Ag
4. Guidelines for writing and balancing chemical equations:
5. Check each atom or polyatomic ion to be sure
that they are equal on both sides of the equation.
Scientific findings 4
6. Make sure that all coefficients are in the lowest
possible ratio. If necessary, reduce to the lowest
ratio. Note: Diatomic Elements such as
H , O , Cl , Br , F , I , N
Cu + AgNO₃ Cu(NO₃)₂ + Ag
2 2 2 2 2 2 2
6. Stoichiometry
is a section of chemistry that involves using relationships
between reactants and/or products in a chemical reaction to
determine desired quantitative data. In Greek, stoikhein means
element and metron means measure, so stoichiometry literally
translated means the measure of elements.
Mole A
Balanced
Equation Mole B
Scientific findings 6
8. Scientific findings 8
8
3.55 moles AgNO₃ X __1 mole Cu
2 moles AgNO₃
Sample 2-If 90.5 grams of Ag was produced, how
many grams of Cu reacted?
Cu + AgNO₃ Cu(NO₃)₂ + Ag
2
1
108
1
1
64
26.81
9. 2NaClO₃
Scientific findings 9
2NaCl + 3O₂
2
1 x 2=2
NaClO₃ NaCl + O₂
=Na=
=Cl=
=O=
1 1
1 1
3 2
1 x 2=2
3 x 2=6
2
2 = 1 x 2
2 = 1 x 2
3
6 = 2 x 3
10. Sample 3
15.00 moles of NaClO₃ will produce how
many grams of O₂?
2NaClO₃
Scientific findings 10
2NaCl + 3O₂
15 moles NaClO₃=______gO₂
15 moles NaClO₃
X
__molesO₂
moles NaClO₃
3
2 X
__gO₂
___mole O₂
1
32
720gO₂
Line up all the elements present in the compound
Think a coefficient that will balance the 2 sides of the equations
To solve mole of substance A to get the mole of the other substance (B), we need to balance the equation
Mass-from the molar mass
Mole-from the balance equation
Mass A of the substance will be converted into Mole A, then Mole A will be converted to Mole B and from Mole B into Mass B of a substance
To get Mass A-get the molas mass
Mole A will need the balanced chemical equation to have Mole B
Correct balanced chem. Eq.
We need 26.81 gCu to produce 90.5 g Ag
