Thea is doing a chemistry experiment. The instructions say she needs to use pure water. Hamza offer her a bottle labelled “100% Pure Spring Water”. Suggest why this water is unlikely to be suitable for the experiment [2] A scientist is comparing 2 samples of the same compound. One is pure and the other is impure. The compound is a solid at room temperature. Explain how the scientist could tell which is the pure compound. [2]

The melting point of pure asprin is 136oC. The melting point of a sample of asprin is measured as being between 128 – 132oC. Give two reasons that suggest the sample is not pure asprin. [2]
Gunpowder is a formulation of potassium nitrate, charcoal and sulphur in the ratio 15 : 3 : 2
What is meant by the term “formulation” [2]
Calculate the mass of charcoal in 40g of gunpowder [1]
if you can just give me hints that would be great