1e- Formule, Equations + Calculations❗️

Question 1

How to work out relative formula mass/Mr?

Answer 1

The sum of the atomic masses of all the elements in a compound

Question 2

How do you workout percentage by mass?

Answer 2

Number of atoms of an element x AR/Mr x 100

Question 3

What is Avagadro number?

Answer 3

6 x 10^23

Question 4

How do you workout moles?

Answer 4

Mass/Mr

Question 5

How do you work out percentage yield?

Answer 5

Actual yield/theoretical yield x 100

Question 6

Give three reasons for less than 100% yield

Answer 6

1- incomplete reactions
2- practical losses during experiment
3- unwanted side reactions

Question 7

How do you workout concentration (mole/dm^3) ?

Answer 7

Amount of substance/volume of solution

Question 8

How do you calculate volume (dm^3)

Answer 8

Amount of substance/concentration

Question 9

How much space will one mole of gas take up?

Answer 9

24dm^3

Question 10

How do you workout amount of gas in moles?

Answer 10

Volume of gas/24

Question 11

Describe Practical: copper (II) oxide by reduction with methane

Answer 11

1- Measure mass of the empty boiling tube
2- place metal oxide into the boiling tube and measure the mass again
3- support the tube by a clamp
4 - heat the copper oxide with a Bunsen burner until it completely changes colour
5- measure mass of the tube remaining metal powder
6- subtract the mass of the tube