C4 - Chemical Calculations

Question 1

Relative atomic mass (Ar)

Answer 1

Number of protons and neutrons

Question 2

Molecular mass (Mr)

Answer 2

The sum of the Ar in a compound

Question 3

Limiting reagent

Answer 3

The substance that is used up in a reaction

Question 4

Percentage yield

Answer 4

The amount of product you actually make as a % of the amount you should theoretically make

Question 5

Percentage yield formula

Answer 5

Actual yield / theoretical yield

Question 6

Atom economy

Answer 6

Is the mass of the product you want to make as a % of the mass of all the products you make

Question 7

Atom economy formula

Answer 7

Mass of useful products / mass of all products

Question 8

Concentration

Answer 8

Measured in grams per dm³ (g/dm³)
or moles per dm³ (mol/dm³)

Question 9

Concentration formula

Answer 9

Mass / volume of solution

Question 10

Moles

Answer 10

Mass / Mr or volume x concentration

Question 11

Volume

Answer 11

Moles x 24

Question 12

Avogadro’s constant

Answer 12

It is the number of particles of any
substance that makes up 1 mole

6.02 × 10^23 mol-1

Question 13

Titrations

Answer 13

Used to measure accurately what volume of acid and alkali react completely