amount of substances in all papers (3.1.2)

Question 1

what is the relative atomic mass (Ar)?

Answer 1

the average mass of one atom compared to one twelfth of the mass of one atom of carbon 12.

no units.

Question 2

what is the relative molecular mass (Mr) ?

Answer 2

the average mass of a molecule compared to one twelfth of the mass of one atom of carbon 12.

for covalent compounds

no units

Question 3

what is the avogadros constant?

Answer 3

the number of particles in a mole.
(6.022x10^23)

Question 4

how do you work out the number of moles in pure solids and liquids?

Answer 4

moles= mass/Mr

units: grams
mol

Question 5

how do you work out the number of moles in pure solids and liquids?

Answer 5

moles= mass/Mr

units: grams
mol

Question 6

how do you work out the mass of 1 mole of pariticles?

Answer 6

avogadros constant X mass of 1 parrticle.

Question 7

how to work out the number of particles?

Answer 7

number of moles x avogadros constant

Question 8

how do you convert kPa to Pa?

Answer 8

x1000

Question 9

how do you convert cm^3 to m^3?

Answer 9

divide by 10^6 or x10^-6

Question 10

how do you convert dm^3 to m^3?

Answer 10

divide by 10^3 or x10^-3

Question 11

how do u convert C to kelvins?

Answer 11

add 273

Question 12

how do you work out the empirical formula and molecular formula from it?

Answer 12

1: set out the elements with
their masses/percentage.
2: divide each mass by their Mr.
3: divide all them by the smallest
value.
4: give whole number ratio in
empirical formula.
5: molecular formula =
n(empirical formula)

Question 13

explain the water of crystallisation practical (hydrated salt)

Answer 13

• weigh an empty crucible.
• add 2g of hydrated calcium
  sulfate to the crucible and
  weigh again.
• heat with a bunsen burner for
  5 mins and let it cool.
• weigh the crucible and
  contents again.
• heat and reweigh again until
  you reach a constant mass to
  ensure salt has become
  anhydrous.