IB1 Chemistry Quantitative 1b. Topic 1: Quantitative chemistry. 1.1 The mole concept and Avogadro’s constant 1.1.1 Apply the mole concept to substances. 1.1.2 Determine the number of particles and the amount of substance (in moles ). 1.2 Formulas
1.1 The mole concept and Avogadro’s constant
1.1.1 Apply the mole concept to substances.
1.1.2 Determine the number of particles and the amount of substance (in moles).
1.2.1 Define the terms relative atomic mass (Ar) and relative molecular mass (Mr).
1.2.2 Calculate the mass of one mole of a species from its formula.
1.2.3 Solve problems involving the relationship between the amount of substance in moles, mass and molar mass.
1.2.4 Distinguish between the terms empirical formula and molecular formula.
1.2.5 Determine the empirical formula from the percentage composition or from other experimental data.
1.2.6 Determine the molecular formula when given both the empirical formula and experimental data.
1.3 Chemical equations
1.3.1 Deduce chemical equations when all reactants and products are given.
1.3.2 Identify the mole ratio of any two species in a chemical equation.
1.3.3 Apply the state symbols (s), (l), (g) and (aq).
1.4 Mass and gaseous volume relationships in chemical reactions
1.4.1 Calculate theoretical yields from chemical equations.
1.4.2 Determine the limiting reactant and the reactant in excess when quantities of reacting substances are given.
1.4.3 Solve problems involving theoretical, experimental and percentage yield.
1.4.4Apply Avogadro’s law to calculate reacting volumes of gases.
1.4.5 Apply the concept of molar volume at standard temperature and pressure in calculations.
1.4.6 Solve problems involving the relationship between temperature, pressure and volume for a fixed mass of an ideal gas.
1.4.7 Solve problems using the ideal gas equation, PV = nRT.
1.4.8 Analyse graphs relating to the ideal gas equation.
1.5.1 Distinguish between the terms solute, solvent, solution and concentration (g dm–3 and moldm–3).
1.5.2 Solve problems involving concentration, amount of solute and volume of solution.
The yield is the amount of product obtained experimentally
Percentage yield= actual yield × 100
Reacts can be:
0.24±0.01g of magnesium react with excess dilute sulphuric acid to give a gas and a solution.
The solution is evaporated and the evaporating basin (mass 28.83±0.01g) weighs 28.03±0.01g with the salt.
Calculate the percentage yield.
Balanced equation for the reaction
STP = 0oC or 273.15 K and 100kPa
Charles’ Law: the volume of a gas is proportional to the Kelvin temperature at constant pressure
V = kT
V1 = T1
The pressure and temperature of a gas are directly proportional at constant volume.
P = kT
P1 = T1
Boyle’s Law: pressure and volume of a gas are inversely proportional at constant temperature.
PV = constant.
P1V1 = P2V2
V ∝ 1/p (at constant T)
V ∝ T(at constant p)
combine to give
V ∝ T/p or
Equal volumes of a gas under the same temperature and pressure contain the same number of particles.
At constant T and p
V ∝ n
pV = constant, R
universal gas constant , R= 8.31 Jmol-1K-1
(units also dm3kPamol-1K-1)
pV = nRT
Where p = pressure
V = volume
T = Kelvin Temperature
n = number of mole
R = 8.31 J mol-1 K-1
Molar volume of any gas at STP
For a gas at a constant temperature and pressure
the volume is proportional to the number of moles.
mole ratio volume ratio
2 H2(g) + O2(g) 2 H2O(g)
2dm3 ? ?
C + O2 CO2
M 12 (gmol-1)
n 0.50 (mol)
solute : salt
solvent : water
solution : salt-water mixture
Mass percentage = Mass of substance/Mass of solution
Volume percent = volume of solute/ total volume
Mol fraction = Xa = na/(na+nb)
Concentration in moldm-3 often represented by square brackets, eg [HCl]
concentration = mass
the mass of a particular solvent that dissolves in a solvent at a given temperature
often in g per 100g H2O
concentration = number of moles
10g of copper sulfate in 25cm3 of water
5g of copper sulfate in 10cm3 of water
0.1mol of copper sulfate in 15cm3 of water
0.01mol of copper sulfate in 5cm3 of water