Balancing Equations
In balancing equations, these are the only numbers you are allowed to change.
Coefficients?
A reaction where two or more substances combine to form one product.
combination reaction
This is the chemistry word for an amount of particles.
a mole
Use n = m/M to calculate the number of moles in 18 g of H₂O.
1 mol
molar mass of oxygen
16 g/mol
You should never change these small numbers in a chemical formula when balancing.
Subscripts
A reaction where one compound breaks down into simpler substances.
decomposition reaction
One mole contains this many particles.
6.02 × 10²³
Calculate the number of moles in 44 g of CO₂.
1 mol
Use the periodic table to find the molar mass of calcium carbonate, CaCO₃
100.1 g/mol
Balance this equation:
H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
This reaction type usually involves a hydrocarbon reacting with oxygen to form carbon dioxide and water.
combustion
6.02 × 10²³ This number is called/named after....
Avogadro’s number / Avogadro
A sample has 2 mol of O₂. Calculate its mass.
64 g
Use the periodic table to find the molar mass of sodium hydroxide
NaOH = 40.0 g/mol
alance this combustion equation:
CH₄ + O₂ → CO₂ + H₂O
CH₄ + 2O₂ → CO₂ + 2H₂O?
Identify the reaction type:
AgNO₃ + NaCl → AgCl + NaNO₃
double displacement reaction
his law says matter is not created or destroyed in a chemical reaction.
law of conservation of mass
Rearrange n = m/M to find the mass of 0.25 mol of CO₂.
11 g
Use the periodic table to find the molar mass of ammonium nitrate, NH₄NO₃
80.0 g/mol
Balance this equation:
Fe + HCl → FeCl₂ + H₂
Fe + 2HCl → FeCl₂ + H₂
Identify the reaction type:
HCl + NaOH → NaCl + H₂O
acid-base reaction or neutralisation
This is the formula used to calculate the number of moles.
n = m/M
Rearrange n = m/M to find the mass of 2.5 mol of H₂O.
45 g
molar mass of copper sulfate pentahydrate, CuSO₄·5H₂O
249.7 g/mol