## Calculations in chemistry - AQA Synergy

### 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

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

### 6

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?

### 7

What is the relative formula mass of Al2(SO4)3? - HIGHER

Ar of Al = 27, Ar of S = 32 and Ar of O = 16

### 8

What is the number of molecules in 23 g of NO2? - HIGHER

(Mr of NO2 = 46)

### 9

What amount of O2 reacts with 4 mol of Al in the following reaction? - HIGHER

4Al + 3O2 → 2Al2O3

### 10

What mass of Al reacts with 96 g of oxygen in the following reaction? - HIGHER

4Al + 3O2 → 2Al2O3

Mr of O2 = 32 and Ar of Al = 27.