AS Level Chemistry A H032/02 Depth in Chemistry

AS Level Chemistry A H032/02 Depth in Chemistry Friday 9 June 2017 – Afternoon Time allowed: 1 hour 30 minutes You must have: • the Data Sheet for Chemistry A (sent with general stationery) You may use: • a scientific or graphical calculator Turn over OCR is an exempt Charity * H 0 3 2 0 2 * 5/31/24, 5:27 PM OCR AS Level Chemistry A 2017 H032 02 QP about:blank 1/16 2 © OCR 2017 Answer all the questions. 1 Barium combines with oxygen, chlorine and nitrogen to form ionic compounds. (a) Barium oxide, BaO, has a giant ionic lattice structure. (i) State what is meant by the term ionic bond. ........................................................................................................................................... ...................................................................................................................................... [1] (ii) Draw a ‘dot-and-cross’ diagram to show the bonding in barium oxide. Show outer electrons only. [2] (iii) Calculate the number of barium ions in 1.50 g of barium oxide. Give your answer in standard form and to three significant figures. number of barium ions = .......................................................... [2] (b) Barium chloride, BaCl2 , is soluble in water. (i) Compare the electrical conductivities of solid and aqueous barium chloride. Explain your answer in terms of the particles involved. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [2] 5/31/24, 5:27 PM OCR AS Level Chemistry A 2017 H032 02 QP about:blank 2/16 3 Turn over © OCR 2017 (ii) Describe the use of aqueous barium chloride in qualitative analysis. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [2] (iii) Hydrated barium chloride can be crystallised from solution. Hydrated barium chloride has the formula BaCl2 •xH2O and a molar mass of 244.3 g mol −1 . Determine the value of x in the formula of BaCl2 •xH O. 2 Show your working. x = .......................................................... [2] (c) Barium nitride is formed when barium is heated with nitrogen. (i) Complete the electron configuration of a nitride ion. 1s2 ................................................................................................................................. [1] (ii) Solid barium nitride is reacted with water, forming an alkaline solution A and an alkaline gas B. Identify A and B. Write an equation, including state symbols, for the reaction. A......................................................................................................................................... B......................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [4] 5/31/24, 5:27 PM OCR AS Level Chemistry A 2017 H032 02 QP about:blank 3/16 4 © OCR 2017