What is the relative formula mass of N2O? Ar of N = 14 and Ar of O = 16.
30
44
46
What is the relative formula mass of Ca(NO3)2? Ar of Ca = 40, Ar 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 dm3 of solution. What is the concentration of the solution?
4.0 g/dm3
0.25 g/dm3
1.0 g/dm3
A solution of potassium chloride has a concentration of 20 g/dm3. What mass of potassium chloride is dissolved in 5 dm3 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