Answers section
Questions 5.1.4 (b)
- State the observations made.
- Iron shows a valency of 2 in its direct combination with sulphur. Name the product and state its formula.
- Write an equation for the reaction between sulphur and iron.
- Explain the observation made on the cooler parts of the test tube.
Answers to Questions 5.1.4 (b) 
- A bright red glow occurs, and a grey-black solid is produced. A yellow substance deposits on the cooler parts of the test tube.
- Iron (II) sulphide; FeS
- Fe(s) + S(s) → FeS(s)
- The vapour of unreacted sulphur undergoes deposition into solid—an indication that although sulphur melts as shown in Figure 5.1.2, it also sublimes.