QUESTION 6 (Start on a new page.)
6.1 The first step in the extraction of zinc from zinc sulphide (ZnS) is the
combustion of ZnS in oxygen. The balanced equation for the reaction is:
6.1.1 Is the reaction above EXOTHERMIC or ENDOTHERMIC? Give a
reason for the answer. (2)
Oxygen gas consists of oxygen molecules.
6.1.2 Define the term molecule. (2)
6.1.3 Draw the Lewis dot diagram of the oxygen molecule (O2 ). (2)
During the reaction above, 7 g ZnS reacts completely with oxygen gas.
Calculate the:
6.1.4 Number of moles of ZnS that has reacted (3)
6.1.5 Mass O2 needed (3)
6.1.6 Volume of SO2(g) produced at STP (4)
6.2 Consider the incomplete equation for the chemical reaction below.
6.2.1 Write down the NAME of the acid in the equation above. (1)
6.2.2 Write down the FORMULA of product X. (2)
6.2.3 Name the type of reaction illustrated above. Choose from ACID-
BASE REACTION, PRECIPITATION REACTION or REDOX
REACTION. Explain the answer. (3)
6.2.4 Briefly describe a test that can be used to verify the formation of
hydrogen gas during the reaction above. (2)
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