14 (B410U10-1) Examiner only 12. (a) Several different compounds containing sodium, chlorine and oxygen exist. One of these decomposes on heating as shown in the equation. 2NaClO3(s) 2NaCl(s) + 3O2(g) (i) What is the oxidation state of chlorine in NaClO3? [1] ..................................................................... (ii) Calculate the maximum volume of gas, measured at 600 K and 1 atm pressure, that can be made by heating 88.0 g of NaClO3. Give your answer to an appropriate number of significant figures. [3] Volume = ........................................................ dm3 (b) The active component of bleach is sodium chlorate(I), NaClO. This is prepared by passing chlorine into aqueous sodium hydroxide. 2NaOH(aq) + Cl2(g) NaClO(aq) + NaCl(aq) + H2O(l) Calculate the atom economy of this process when used to prepare sodium chlorate(I). [2] Atom economy = ........................................................ % © WJEC CBAC Ltd. (B410U10-1) Turn over. 15 Examiner only (c) Another compound containing sodium, chlorine and oxygen has the following composition by mass. Na 18.8 % Cl 29.0 % O 52.2 % Calculate its empirical formula. [2] Empirical formula ....................................................... © WJEC CBAC Ltd. 8