C4- Chemical Calculations

Question 1

Equation linking Mass, Moles & Molar Mass

Answer 1

m= n x M
mass= moles x molar mass

Question 2

What mass of Mg is required to rect to give 10g of H2? (METHOD)

Answer 2

Balance
Boxes
Moles
Ratio
Mass

Question 3

Calculating Limiting Reactant: METHOD

Answer 3

Balance
Mass
———
Mr/Ar
Moles
Ratio

Question 4

Yield of a Product: METHOD

Answer 4

Balance 
Boxes
Moles
Ratio
Mass

Question 5

Percentage Yield

Answer 5

% Yield= Actual Yield
——————x 100%
Theoretical Yield

Question 6

Atom Economy

Answer 6

= m of atoms in product
—————————— x 100
m of atoms in reactants

Question 7

Concentration (g/dm3) (2)

Answer 7

= mass of solute
———————
Volume of solution

= conc (mol/dm3) x Mr/Ar

Question 8

Increase concentration

Decrease concentration

Answer 8

Increase: add more solute to same vol of solvent
Decrease: add more solvent

Question 9

Titration Calculation

Answer 9

n= c x V

no• moles= conc x Volume

Question 10

Volume of a mole of gas

Answer 10

1 mole of ANY GAS at rm temp &, pressure = 24dm3

molar volume

Question 11

Volume of Gases (2)

Answer 11

n= V dm3
———
24

n= V cm3
———
2400