GYSS 2024 4E Chemistry Prelims Paper 2_QP Final

2 Section A Answer all questions. 1 Table 1.1 shows a list of substances. Table 1.1 ammonium carbonate barium chloride copper(II) sulfate potassium oxide silicon dioxide silver chloride sulfur dioxide zinc carbonate zinc sulfate Use the list of substances to answer the following questions. Each substance can be used once, more than once, or not at all. (a) Which substance(s) can be prepared by the reaction of a metal with a dilute acid? ………………………………………………………………………………………………. [1] (b) Which substance(s) will turn moist blue litmus paper red? ………………………………………………………………………………………………. [1] (c) Which substance(s) can be prepared by precipitation? ………………………………………………………………………………………………. [1] (d) Which substance(s) can react with both acids and alkalis to form gaseous products? ………………………………………………………………………………………………. [1] [Total: 4]

3 2 Separate beams of protons, neutrons and electrons are passed through an apparatus shown in Fig 2.1 . The apparatus contains a positively -charged plate and a negatively - charged plate, which sets up an electric field. Fig 2.1 Sub-atomic particles behave differently in the apparatus depending on their masses and charges. (a) (i) Draw an arrow to indicate the path of the particle which will be deflected the most by the electric field, and label the name of the particle. [1] (ii) Explain your answer. ………………………………………………………………………………………... ………………………………………………………………………………………... [1] (b) (i) In nuclear reactions, protons or neutrons are accelerated to high speeds and fired as ‘nuclear bullets’ at the nucleus of an atom of an element. Suggest why protons are less effective ‘nuclear bullets’ than neutrons. ………………………………………………………………………………………... ………………………………………………………………………………………... [1] (ii) When neutrons are fired at nucleus of atoms, the neutrons may become part of the nucleus of those atoms. Explain the effect of the presence of an extra neutron on the chemical properties of the new atoms formed. ………………………………………………………………………………………... ………………………………………………………………………………………... [1] [Total: 4] + – positively charged negatively charged beam of sub-atomic particles

4 3 Boron trifluoride, BF3 is often used as a versatile building block for other boron compounds. Fig 3.1 shows the bonding in a boron trifluoride molecule, showing only outer electrons. Fig 3.1 (a) Give a reason why the bonding in BF3 is typical and one reason why it is not typical of similarly bonded compounds. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. [2] (b) Boron trifluoride can react with caesium fluoride to form caesium tetrafluoroborate. BF3 + CsF → CsBF4 Caesium tetrafluoroborate consists of caesium cations and tetrafluoroborate anions. Tet