3.1.2 Amount of substance

Question 1

relative atomic mass

Answer 1

+ the average mass of one atom of an element relative to 1/12 the mass of one atom of carbon-12

Question 2

relative molecular mass

Answer 2

+ the average mass of a molecule relative to 1/12 the mass of one atom of carbon-12

Question 3

what is a mole?

Answer 3

+ the amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12

Question 4

what is Avogardo’s Constant

Answer 4

6.022 x 10^23

Question 5

how do you calculate moles in pure solids,liquids and gases?

Answer 5

moles = mass / Mr

Question 6

how do you work out moles for gases?

Answer 6

PV = nRT

volume in m^3

Question 7

how do you work out moles for solutions?

Answer 7

concentration = moles/ volume

volume in dm^3

Question 8

how to calculate no. of particles?

Answer 8

moles of substances (in mol) x Avogadro’s Constant

Question 9

how to calculate density?

Answer 9

density = moles / volume

Question 10

what is an empirical formulae?

Answer 10

+ an empirical formula is the simplest ratio of atoms of each element in the compound

Question 11

what is molecular formula?

Answer 11

+ the actual number of atoms of each element in the compound