XMS SEC 3 WA2 2022 QP

3 6092/Chemistry/2022 WA2 Section A [5 marks] Answer all questions. Write your answers in the boxes provided at the end of the Section. 1 Copper is used in electrical wirings to conduct electricity. Why is copper able to conduct electricity? A Copper has a ‘sea’ of delocalised electrons. B Copper has free-moving ions. C Copper has a ‘sea’ of delocalised ions. D Copper has free-moving atoms. 2 Calcium phosphate is the main mineral found in human bones and teeth. What is the chemical formula of calcium phosphate? A CaPO3 B CaPO4 C Ca3(PO3)2 D Ca3(PO4)2 3 The following chromatogram was obtained by a student. What is the R f value of the spot marked ‘X’? A 8 3 + 8 B 3 3 + 8 C 3 + 8 8 D 3 8

4 6092/Chemistry/2022 WA2 4 A solid substance was found to be unable to conduct electricity. When pure water was used to dissolve the substance, the solution could conduct electricity. What could be the structure of the substance, and why can the solution conduct electricity? Structure Reason for being able to conduct electricity A giant metallic structure Water can conduct electricity. B giant metallic structure It has free-moving electrons. C giant ionic structure It has free-moving ions. D giant ionic structure Water can conduct electricity. 5 The following diagram shows a set -up used to obtain clean water from dirty river water in a rural village. Which method of separation is used to obtain clean water in this case? A using a separating funnel B filtration C distillation D evaporation Write your answers for Section A in the boxes below. 1. 2. 3. 4. 5. [Total: 5]

5 6092/Chemistry/2022 WA2 Section B [30 marks] Answer all questions. Write your answers in the spaces provided. B1 Use the list of substances to answer the questions. sulfur dioxide graphite oxygen sodium sulfate dry ice (a) (i) Which substance is ionic? ……………………………………………………………………………………… [1] (ii) Which substance has a giant molecular structure? ……………………………………………………………………………………… [1] (iii) Which two substances contain two elements from Group VI? ……………………………………………………………………………………… [1] (iv) If the substances above were mixed, which substance can be obtained by sublimation? ……………………………………………………………………………………… [1] (v) Which substance can conduct electricity in the solid state? ……………………………………………………………………………………… [1] (vi) Write down the chemical formula for one of the compounds. ……………………………………………………………………………………… [1] (b) Draw the ‘dot’-and-‘cross’ diagram for ammonia. Show outer electrons only. [2] [Total: 8 marks]

6 6092/Chemistry/2022 WA2 B2 Write down a method of separation used to obtain the underlined component of the mixture below. (a) (i) oil and water ………………………………………………………………………………………….