Amount of Substance

Question 1

Definition of a Mole

Answer 1

6.02 x 10(23) particles

Question 2

Equation linking Moles (n), Relative Molecular Mass (Mr), and mass (m)

Answer 2

n = m/Mr

Question 3

Equation linking Moles (n), Concentration (c), and Volume (v)

Answer 3

n = c x v

Question 4

The ideal Gas equation

Answer 4

pV = nRT
p= Pressure (Pa)
V= Volume (m(3))
n= number of Moles
R= Gas Constant ()
T= Temperature (k)

Question 5

How to make a Standard Solution

Answer 5

1. work out how many moles of NaOH are needed using the formula n = c x v
2. work out how many grams of NaOH are needed using the formula m = n x Mr
3. place a weighing bottle on a digital balance and weight out the mass of solid needed and place in a beaker
4. weigh the weighing bottle and work out mass of solid
5. add distilled water to the beaker and stir until all the NaOH is dissolved
6. tip the solution into a 250cm3 volumetric flask using a funnel, rinse all apparatus with distilled water
   top up flask until solution’s meniscus is at the bottom of the line
7. stopper and mix
8. calculate exact concentration of standard solution

Question 6

How to do a Titration

Question 7

Definition of Empirical Formula

Answer 7

The smallest whole number ratio of atoms of each element present in a compound

Question 8

Definition of Molecular Formula

Answer 8

The actual numbers of atoms in a molecule

Question 9

How to calculate the molecular formula with the empirical formula and Relative Molecular Mass

Answer 9

1. Find empirical mass (relative mass of empirical formula)
2. divide Relative Molecular Mass by Relative Empirical mass
3. Multiply empirical formula by that number

Question 10

Definition of Theoretical Yield

Answer 10

The mass of product that should be formed in a chemical reaction

Question 11

Equation for Percentage Yield

Answer 11

Percentage Yield = Actual Yield/Theoretical Yield x100

Question 12

Definition of Atom Economy

Answer 12

A measure of the proportion of reactant atoms that become part of the desired product

Question 13

Advantages of high Atom Economy

Answer 13

Less waste
More bang for buck
More sustainable

Question 14

Equation for Atom Economy

Answer 14

% Atom Economy = molecular mass of desired product/sum of molecular mass of all reactants x100

Question 15

Definition of Water of Crystallisation

Answer 15

When some compounds can form crystal which have water as part of their structure

Question 16

Water of crystallisation practical