Relative formula masses can be calculated and used in conservation of mass calculations. Calculations can be carried out to find out concentrations of solution and uncertainties in measurements.

What is the relative formula mass of N_{2}O? A_{r} of N = 14 and A_{r} of O = 16.

30

44

46

What is the relative formula mass of Ca(NO3)_{2}? A_{r} of Ca = 40, A_{r} of N = 14 and Ar of O = 16.

70

102

164

What does the law of conservation of mass state?

No atoms are lost or made in a chemical reaction

Atoms are lost but not made in a chemical reaction

Atoms are made but not lost in a chemical reaction

Which of these is an example of a non-enclosed system?

A boiling tube in which two solutions react to form a solution and a precipitate

A test tube in which calcium carbonate is heated

A beaker in which an acid neutralises an alkali to form a salt solution

A stopwatch has scale divisions of 0.5 seconds. What is the best estimate of uncertainty of its readings?

0.1 s

0.25 s

0.5 s

What is the range of this set of readings: 1.2 cm, 1.1 cm, 1.3 cm, 1.2 cm?

1.2 cm

1.3 cm

0.2 cm

What is the mean and best estimate of the uncertainty for this set of readings: 61.0 s, 63.0 s, 62.0 s, 62.5 s, 61.5 s?

61.0 ± 0.1 s

62.0 ± 0.2 s

62.0 s ± 1.0 s

2.0 g of copper sulfate is dissolved in 0.5 dm^{3} of solution. What is the concentration of the solution?

4.0 g/dm^{3}

0.25 g/dm^{3}

1.0 g/dm^{3}

A solution of potassium chloride has a concentration of 20 g/dm^{3}. What mass of potassium chloride is dissolved in 5 dm^{3} of the solution?

4 g

100 g

0.25 g

Which of these actions will decrease the concentration of a solution? - Higher

Adding more solute

Evaporating some solvent

Adding more solvent