Chapter 3 - Amount of substance

Question 1

Amount of substance

Answer 1

quantity whose unit of the mole, used as a means of counting any species such as atoms, ions and molecules

Question 2

Avogadro constant (Na)

Answer 2

the number of particles per mole of the Carbon-12 isotope (6.02x1023 mol-1)

Question 3

Molar mass (M)

Answer 3

the mass per mole of a substance, in units of gmol-1

Question 4

Molecular formula

Answer 4

formula that shows the number and type of atoms of each element present in a molecule

Question 5

Empirical formula

Answer 5

formula that shows the simplest whole number ratio of atoms of each element present in a compound

Question 6

Relative molecular mass (Mr)

Answer 6

weighted mean mass of a molecule of a compound compared with 1/12th of the mass of an atom of Carbon-12

Question 7

Relative formula mass

Answer 7

weighted mean mass of the formula unit of a compound compared with 1/12th of the mass of an atom of Carbon-12

Question 8

Water of crystallisation

Answer 8

water molecules that are bonded into a crystalline structure of a compound

Question 9

Standard solution

Answer 9

a solution of known concentration

Question 10

Molar gas volume (Vm)

Answer 10

volume per mole of gas molecules at a stated temperature and pressure

Question 11

Stoichiometry

Answer 11

the ratio of the amount, in moles, of each substance in a chemical equation (essentially the ratio of the balancing numbers)

Question 12

Theoretical yield

Answer 12

the yield resulting from complete conversion of reactants into products

Question 13

Actual yield

Answer 13

the amount of product obtained from a reaction

Question 14

Limiting reagent

Answer 14

the reactant that is not in excess, which will be used up first and stop the reaction