6.3. Reversible reactions and equilibrium
A subsection of Chemistry, 0620, through 6. Chemical reactions
Listing 10 of 390 questions
Sulfuricacid is made from sulfur in a four-stage process. stage 1 Sulfur is converted into sulfurdioxide. stage 2 Sulfurdioxide is converted into sulfurtrioxide. stage 3 Sulfurtrioxide is converted into oleum. stage 4 Oleum is converted into sulfuricacid. How is sulfur converted into sulfurdioxide in stage1? Describe how sulfurdioxide is converted into sulfurtrioxide in stage2. Your answer should include: ● ● an equation for the reaction ● ● the temperature used ● ● the name of the catalyst used. The reaction in stage2 can reach equilibrium. What is meant by the term equilibrium? Sulfurtrioxide is converted into oleum, H2S2O7, in stage3. What is sulfurtrioxide reacted with to convert it into oleum? Oleum is converted into sulfuricacid in stage4. Write a chemical equation for the conversion of oleum, H2S2O7, into sulfuricacid. When copper is reacted with hot concentrated sulfuricacid, sulfurdioxide gas is formed. Balance the chemical equation for this reaction. Cu + H2SO4 → CuSO4 + SO2 + H2O Sulfurdioxide is a reducing agent. Give the colour change that occurs when excess sulfurdioxide is bubbled into acidified aqueous potassiummanganate(. starting colour of the solution final colour of the solution  When sulfuricacid reacts with ammonia the salt produced is ammoniumsulfate. Write the chemical equation for this reaction. Bariumsulfate is an insoluble salt. Bariumsulfate can be made from aqueous ammoniumsulfate using a precipitation reaction. Name a solution that can be added to aqueous ammoniumsulfate to produce a precipitate of bariumsulfate. Write an ionic equation for this precipitation reaction. Include state symbols. 
0620_s20_qp_42
THEORY
2020
Paper 4, Variant 2
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Dinitrogentetroxide, N2O4, decomposes into nitrogendioxide, NO2. The reaction is reversible. N2O42NO2colourless gas brown gas A gas syringe containing a mixture of dinitrogentetroxide and nitrogendioxide gases was sealed and heated. After reaching equilibrium the mixture was a pale brown colour. end sealed plunger mixture of dinitrogen tetroxide and nitrogen dioxide State what is meant by the term equilibrium. The plunger of the gas syringe is pushed in. The temperature does not change. The mixture initially turns darker brown. After a few seconds the mixture turns lighter brown because the equilibrium shifts to the left. N2O42NO2colourless gas brown gas Explain why the mixture initially turns darker brown. Explain why the position of equilibrium shifts to the left. The forward reaction is endothermic. State what happens to the position of equilibrium when the temperature of the mixture is increased. State what happens to the rate of the forward reaction and the rate of the backward reaction when the temperature of the mixture is increased. rate of the forward reaction rate of the backward reaction  
0620_s21_qp_41
THEORY
2021
Paper 4, Variant 1
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Hydrogeniodide, HI, decomposes into iodine and hydrogen. The reaction is reversible. 2HII2+ H2colourless gas purple gas colourless gas A gas syringe containing a mixture of hydrogeniodide, iodine and hydrogen gases was sealed. After reaching equilibrium the mixture was a pale purple colour. end sealed plunger equilibrium mixture of hydrogen iodide, iodine and hydrogen State what is meant by the term equilibrium. The plunger of the gas syringe is pushed in. The position of equilibrium does not change. The colour of the gaseous mixture turns darker purple. The temperature remains constant. 2HII2+ H2colourless gas purple gas colourless gas Explain why the position of equilibrium does not change. Suggest why the colour of the gaseous mixture turns darker purple even though the position of equilibrium does not change. The forward reaction is endothermic. State what happens to the position of equilibrium when the temperature is decreased. State what happens to the rate of the forward reaction and the rate of the backward reaction when the temperature of the mixture is decreased. rate of the forward reaction rate of the backward reaction  
0620_s21_qp_43
THEORY
2021
Paper 4, Variant 3
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