Calculations

Question 1

Relative Atomic Mass

Answer 1

The mean mass of an element compared to C-12 (mass number of all elements added together then divided by the number of elements or 100 for a percentage)

Question 2

Relative Formula Mass

Answer 2

The sum of relative atomic masses of all the atoms or ions in its formula

Question 3

Molecular formula

Answer 3

The actual number of atoms of each element in one molecule

Question 4

Empirical formula

Answer 4

The simplest ratio of different atoms in it

Question 5

Number of moles

Answer 5

Mass / Ar

Question 6

Empirical formula work out

Answer 6

List elements. Experimental masses. Divide by Arn divide by smallest value. Give ratio of atoms

Question 7

Calculating masses in reactions

Answer 7

Write balanced equation. Find Mr of needed and of given. Multiply by big numbers (coefficients). Divide to find 1 then multiply to find all

Question 8

Concentration

Answer 8

Mass of solute / volume of solvent