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5a.   [1 mark]   Students were asked to investigate how a change in concentration of hydrochloric acid, HCl, affects the initial rate of its reaction with marble chips, CaCO 3 . They decided to measure how long the reaction took to complete when similar chips were added to 50.0 cm 3  of 1.00 mol dm −3  acid and 50.0 cm 3  of 2.00 mol dm −3  acid. Two methods were proposed: (1) using small chips, keeping the acid in excess, and recording the time taken for the solid to disappear (2) using large chips, keeping the marble in excess, and recording the time taken for bubbles to stop forming. Annotate the balanced equation below with state symbols. CaCO 3 (__) + 2HCl(__) → CaCl 2 (__) + CO 2 (__) + H 2 O(__)   5b.   [1 mark]   Neither method actually gives the initial rate. Outline a method that would allow the initial rate to be determined.   5c.   [1 mark]   Deduce, giving a reason, which of the...
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chapter 7 test

  2a. [1 mark]   A mixture of 1.00 mol SO 2 (g), 2.00 mol O 2 (g) and 1.00 mol SO 3 (g) is placed in a 1.00 dm 3 container and allowed to reach equilibrium. 2SO 2 (g) + O 2 (g) --> 2SO 3 (g) Distinguish between the terms reaction quotient, Q, and equilibrium constant, K c .   2b. [2 marks]   The equilibrium constant, K c , is 0.282 at temperature T. Deduce, showing your work, the direction of the initial reaction.
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