amount of substance

Question 1

definition for Ar and Mr?

Answer 1

Ar: average mass of one atom of an element compared to 1/12th the mass of one atom of carbon 12
Mr: average mass of one molecule compared to 1/12th the mass of one atom of carbon 12

Question 2

definition of empirical formula:
what are 2 errors to the magnesium oxide experiment?
why do we stop till we get a constant mass of the copper sulphate or whatever in water crystallisation?
when working out water of crystallisation what formula in the spec is it similar to?

Answer 2

• the simplest whole number ratio of ATOMS OF EACH ELEMENT in a compound
• magnesium oxide escaping AND magnesium oxide not being completely burnt
• so all water you could possibly lose is lost
• empirical