Quantitative Chemistry

Question 1

What is relative formula mass

Answer 1

All the relative atomic masses added together

Question 2

what is Ar

Answer 2

• Relative atomic mass
• big number of an atom
• protons and neutrons added together

Question 3

Formula of percentage mass of an element in a compound

Answer 3

%mass = Ar x number of atoms of that element/ Mr

Question 4

What is Mr

Answer 4

Relative formula mass

Question 5

Formula for moles

Answer 5

Moles = mass/Mr

Question 6

The actual number of avogadro’s constant

Answer 6

6.02 x 10^23

Question 7

What is the relevance of avogadro’s constant

Answer 7

• one mole of any substance is just an amount of that substance that contains avogadros number
• so one mole of anything is equal to 6.02 x 10^23 particles

Question 8

How to do those really hard questions that ha to do with moles were they ask you to work out x or something

Answer 8

• mass of reactant and products should be the same so work out mass of products
• work out Mr of products
• work out moles of products
• then divide the moles by the smallest mole
• should give you whole numbers
• then you can balance equation

Question 9

Relationship between amount of product formed and amount of limiting reactant

Answer 9

• directly proportional
• for example if. You halve the amount of limiting reactant, the amount of product formed will also halve

Question 10

How to work out mass of product formed in a reaction by using the mass of the limiting reactant and the balanced equation

Answer 10

1. Write out a balanced equation
2. Work out Mr of the reactant an product you want
3. Find out how many moles there are of the substance you know the mass of
4. Use the balanced equation to work out how many moles there’ll be of the other substance
5. Use number of moles to calculate the mass

Question 11

Formula of concentration

Answer 11

Concentration (g/dm^3) = mass/ volume (dm^3)

Question 12

What is 1dm^3 equal to in cm

Answer 12

1000cm^3