1. CC9 - Calculating Involving Masses (p26-30)
2. Using the periodic table – find the mass of the elements below using a periodic table
3. Relative formula mass - calculate the formula mass of the following compounds
H20
CO2
CH4
NH3
H2SO4
(NH3)2NO3
1. Define -
Formula mass
Atomic Mass
Empirical formula
Yield
1: O : C :Mg :Ca :N
4. Empirical formula (the simplest ratio of atoms in a compound) e.g. The empirical formula of C2H4 (ethene) is CH2.
What is the empirical formula of the following?
C2H6
C4H8
H2O
C6H12O6
In a reaction 20g of calcium reacts with 6g of carbon and 24g of oxygen.
5. Calculating % yield - identify two figures, the predicted yield and the actual yield the use the equation:
% Yield = Actual Yield x
Predicted yield
Calculate predicted yield in the following experiment.
40g of CO2 produced when CaCO3 is heated when the expected yield was 44g
80g of CaCO3 produced when CaCO3 heated when the expected yield was 100g
7. Calculating concentration - divide the mass dissolved by the volume (in litres).
Concentration (g/dm3)= mass (g)
volume (dm3)
1 25g of copper sulphate is dissolved in 500cm3 of water.
2 What is the mass of sodium chloride in 300cm3 of solution with concentration of 12g/dm3
8. (Higher) Moles is the name given to a certain number of particles.
1 mole = 6.02x1023 particles
How many particles in a mole of oxygen?
How many particles in 4 moles of nitrogen?
9. (Higher) Moles - calculating the number of moles in a mass of compound.
Use the equation Number of moles = Mass of compound
Formula mass of compound
How many moles in 18g of H2O.
How many moles in 200g of CaCO3.
How many moles in 48g of CH4.
What is the mass of 4 moles of CO2
6. Converting dm3 --> cm3
1000 cm3 = 1 dm3 = 1 litre
20 cm3 = _____dm3
_____cm3 = 0.76dm3

2. CC9 Calculating With Mass (p26-30)
Moles is the name given to a certain number of particles.
It is 6.02x1023.
How many particles in a mole of oxygen? x 1023
How many particles in 4 moles of nitrogen? 2.4 x 1024
Calculating % Yield.
You need to identify two figures, the predicted yield and the actual yield the use the equation:
% Yield = Actual Yield x
Predicted yield
Calculate predicted yield in the following experiment.
40g of CO2 produced when CaCO3 is heated when the expected yield was 44g
91%
80g of CaCO3 produced when CaCO3 heated when the expected yield was 100g 80%
Define:
Formula mass: mass of all atoms in a molecule or compound
Atomic Mass: mass of protons and neutrons
Empirical formula: simplest ration of atoms in a compound
Yield: mass produced in an experiment
You must use the mass figures from the periodic table symbols
Calculating the number of moles in a mass of compound.
Use the equation Number of moles = Mass of compound
Formula mass of compound
How many moles in 18g of H2O
How many moles in 200g of CaCO
How many moles in 48g of CH
What is the mass of 4 moles of CO
What is the mass of the following elements?
1,O ,C , Mg , Ca , N 14
Finding empirical formula.
Calculating concentration.
Simply divide the mass dissolved by the volume (in litres).
Concentration (g/dm3)= mass (g)
volume (dm3)
1 25g of copper sulphate is dissolved in 500cm3 of water.
50g/dm3
2 What is the mass of sodium chloride in 300cm3 of solution with concentration of 12g/dm3
3.6g
Calculate the formula mass of the following compounds? H
CO2 44
CH4 16 NH
H2SO4 98
(NH3)2NO3 96
Find the empirical formula in the following:
In a reaction 20g of calcium reacts with 6g of carbon and 24g of oxygen.
CaCO3
1dm3 = 100cm3 =1000ml = 1litre
Empirical formula is the simplest ratio of atoms in a compound.
e.g. The empirical formula of C2H4 (ethene) is CH2.
What is the empirical formula of the following?
C2H CH3
C4H C2H4
H2O H2O
C6H12O CH2O