Edexcel 3 Welcome to your Edexcel 3 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 The formation of ammonia from nitrogen and hydrogen is exothermic. Under equilibrium, what change would increase the 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. They lower the activation energyII. They increase product yield in equilibrium reactionsIII. They increase the equilibrium constant I only I and II only I and III only I, II and III In the Haber process, the maximum yield is achieved by... Increasing the pressure Decreasing the pressure Using a catalyst Decreasing the rate of reaction Which of the following do not affect the value of Kp?I. TemperatureII. PressureIII. Concentration II and III only III only II only I and III only Both the position of equilibrium and the value of Kc or Kp will change if... The temperature is altered The pressure is altered The concentration is altered The rate of reaction is altered A mixture has a total pressure 2kPa, contains 0.2 mol of nitrogen and 0.6 mol oxygen. What is the partial pressure of nitrogen gas in the mixture? 0.5 1.5 0.75 0.25 Which of the following statements is incorrect? Kw is constant at all temperatures Increasing the temperature causes a decrease in the pH of water Kw is derived from Kc Unit of Kw is mol2/dm6 Assuming complete dissociation, what is the pH of 0.5M potassium hydroxide (KOH)? 13.7 13 10.6 14 What is an acidic buffer is made of? A solution of weak acid an its salt A solution of salt of a weak acid A weak acid A weak base Which of the following statements is correct?I. Ethalpy of neutralisation of weak acids is more exothermicII. Methyl orange is best used with strong acid titrationsIII. Strong acids partially dissociate II only I and II only I only I, II and III Which of the following is the definition of a Bronsted-Lowry acid? It is a proton donor It is a proton acceptor It is an electron donor It is an electron acceptor A strong acid at pH 3 is diluted 100 times its original volume. What is most likely to be its pH after dilution? 5 1 7 9 Which of the following orders is correct such that the first compound has the most negative lattice enthalpy and the last one has the least negative? MgO, BaCl<sub>2</sub>, KCl KCl, BaCl<sub>2</sub>, MgO BaCl<sub>2</sub>, MgO, KCl KCl, MgO, BaCl<sub>2</sub> First electron affinity values will become less exothermic as you go... down Group 7 up Group 7 towards the left on the periodic table from non-metals to metals What causes difference in theoretical and Born-Harber lattice enthalpies? Polarisation of negative ion 100% ionic character of compound Spherical shape of ions All of the options What can be said about entropy change when solid ammonium chloride decomposes to ammonia and hydrogen chloride gas? It is positive It is negative It remains the same It is unpredictable Which of the following increases the polarising power of cation?(i) The positive ion has multiple charges (ii) The positive ion is small i and ii i only ii only both are incorrect What material is used as the electrode of standard hydrogen electrode (SHE)? Platinum Silver Copper Titanium Which of the following statements is true? More negative half cell oxidises More negetive half cell reduces Powerful oxidising agents have lower oxidation numbers Which of the following is usually used for making a salt bridge? Potassium nitrate Sodium oxide Carbonate ion Iron III chloride To make the electrode a standard reference electrode, hydrogen gas must be at a pressure of... 100 kPa 100 Pa 1000 kPa 1000 Pa A fuel cell uses the energy from the reaction of a fuel with oxygen to create... Voltage Current Energy Power Which of the following can cause a colour change in compounds of a transient element?I. LigandII. Coordination numberIII. Oxidation state I, II, and III I and II only III only I only Time is Up!