CIE Physical Chemistry Quizz 3 Welcome to your CIE Physical Chemistry Quizz 3 All uncombined elements have an oxidation number of zero 1 -1 2 If the oxidising agent in an experiment is Bromine water, then it can be classified as? electron acceptor electron donor isotope transition element When sulphur dioxide is formed from sulphate ions, what is the change in oxidation number of sulphur? .+6 to +4 .+4 to+6 no chnage .+4 to 0 Which of the following is true about hydrogen fuel cell? All the statements are true Oxygen gains electrons at one electrode. Hydrogen gives electrons at one electrode. Water is formed as the result of reactions at electrode What happens to a reactant in disproportionation reaction? oxidises and reduces oxidises only reduces only breaks into elements Oxidation number of Carbon in carbonate ion is? .+4 -4 .+2 -6 What is the unit of equilibrium constant for the equilibrium of reation between chlorine and hydrogen gas to form hydrogen chloride gas? No units mol/dm3 mol2/dm6 dm3/mol Dynamic equilibrium occurs when forward and backward reactions are occurring at equal rates zero rate fast rate slow rate Le Chatelier’s principle states that if an external condition is changed the equilibrium will shift to oppose the change products reactants atomic spin Stage 2 reaction of contact process is exothermic. What would increase the product yield? Decrease in temperature Increase in temperature Vanadium(V) oxide catalyst vacuum conditions A catalyst has no effect on the position of equilibrium rate of reaction reactants products If Kc is small we say the equilibrium favours the reactants products reaction rate position of equilibrium Formation of ammonia from nitrogen and hydrogen is exothermic. Under equilibrium what change would increase yield of ammonia the most? Increasing pressure; decreasing temperature Increasing temperature; decreasing pressure Increasing pressure; increasing temperature Decreasing pressure; decreasing temperature Which of the following is true about catalysts? I only I and II only I and III only I, II and III In haber process the maximum yield is achieved by increasing the pressure decreasing the pressure using a catalyst decreasing the rate of reaction Time is Up!