Topic 5: Formulae, Equation, Amounts

Question 1

What is Avogadro’s number

Answer 1

6.02 x 10^23

Question 2

What is a mole

Answer 2

the unit for an amount of a substance

Question 3

What is the Molar mass of a substance

Answer 3

mass per mole of the substance in g mol-1

Question 4

What is meant by the term ‘empirical formula’?

Question 5

What is meant by the term ‘molecular formula’?

Question 6

What is the ideal gas equation, and what are the units

Answer 6

pV = nRT

p = Pressure = 1 atm or 1,000,000 Pa
V = Volume = m3
n = Moles
R = gas constant = 8.31kJmol-1
T = temperature in Kelvin (Celsius + 297)

Question 7

Equation to calculate mass

Answer 7

Mass = Mr x n

Question 8

Equation to calculate concentration

Answer 8

C = moles / volume

Question 9

Equation to calculate percentage uncertainty

Answer 9

% = (margin of error / volume) x 100

Question 10

Equation to calculate Atom economy

Answer 10

Atom economy of a reaction = (Mr desired product / Mr total reactants) x 100

Question 11

Equation to calculate % yield

Answer 11

Percentage Yield = (actual / theoretical) x 100