# Calculations in chemistry - AQA test questions - AQA Trilogy

### 1

What is the relative formula mass of N2O? Ar of N = 14 and Ar of O = 16.

### 2

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

### 3

What does the law of conservation of mass state?

### 4

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

### 5

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

### 6

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

### 7

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?

### 8

2.0 g of copper sulfate is dissolved in 0.5 dm3 of solution. What is the concentration of the solution?

### 9

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?

### 10

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