Question

(a) Substances are separated from mixtures of substances using different methods.
Draw one straight line from each substance to the correct method of separating it from the mixture.
One line has been drawn for you.

(b) One reason for separating mixtures is to purify substances.
Explain the importance of purity in the manufacture of substances used in food additives.
(c) The element lead is obtained from the compound lead(II) bromide by electrolysis.
(i) Describe the difference between an element and a compound.
(ii) Complete the sentences to describe the electrolysis of lead(II) bromide.
Electrolysis is the breakdown of molten lead(II) bromide by the passage of ………………………………………… .
The gas released at the positive electrode is ………………………………………… and ………………………………………… is formed at the negative electrode.
The negative electrode is called the ………………………………………… .
(d) A student reacts dilute hydrochloric acid with four metals.
The student’s observations are shown in Table 5.1.

Place the four metals in order of their reactivity from the most reactive to the least reactive.