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Reaction rates and reversible reactions questions and answers

Reaction rates and reversible reactions questions and answers. Answers are in video format.

Lessons (32)

• 1.    When bromine gas reacts with aqueous sodium hydroxide, the equilibrium represented by the equation: #Br_2(aq)+2OH^(-) (aq) overset(rightarrow)(leftarrow) Br^(-) (aq)+OBr^(-)(aq)+H_2O#(I) is established. What observation would be made if a few drops of sulphuric (VI) acid were added to the equilibrium mixture? Explain.
  1m 11s

• 2.    During the production of hydrogen iodide, hydrogen reacts with iodine according to the equation: #H_2(g)+I_2(g)overset(rightarrow)(leftarrow) 2HI(g)#; H=52.0 kJ Explain how the following would affect the yield of hydrogen iodide: (a) Increase in temperature. (b) Increase in pressure.
  1m 34s

• 3.    Ammonia can be converted to nitrogen (II) oxide asshown in the equation below. #4NH_3(g)+5O_2(g)overset(rightarrow)(leftarrow)4NO(g)+6H_2O(g)# (a) Explain how an increase in temperature would affect the yield of nitrogen (II) oxide. (b) On the energy level diagram above, sketch the energy level diagram that would be obtained if the reaction is carried out in the presence of a platinum catalyst.
  2m 2s

• 4.    The decomposition of calcium carbonate can be represented by the equation: #CaCO_3(s) overset(rightarrow)(leftarrow) CaO(s)+CO_2(g)# Explain how an increase in pressure would affect the equilibrium position.
  0m 54s

• 5.    A dynamic equilibrium between dichromate and chromate ions is established as shown in the equation below: #Cr_2O_7^(2-)(aq)+2OH^(-) (aq) overset(rightarrow)(leftarrow) 2 CrO_4^( 2-) (aq)+H_2O(I)# (a) What is meant by dynamic equilibrium? (b) State and explain the observation that would be made if a few pellets of potassium hydroxide are added to the equilibrium mixture.
  1m 21s

• 6.    The curves below represents the changes in the concentration of substance E and F with time in the reaction; E(e) #overset(rightarrow)(leftarrow)# F(g) (a) Which curve represents the change in concentration of substance F? Give a reason. (b) Give a reason for shapes of curves after time ‘t’ minutes.
  1m 21s

• 7.    Under certain conditions, carbon (IV) oxide reacts with water to form methanol (#CH_3OH)# and oxygen as shown below: #2CO_2(g)+4H_2O(I)overset(rightarrow)(leftarrow) 2CH_3OH(I)+3O_2(g)#: H= +1452kJ What would be the effect on the yield of methanol if the temperature of the reaction mixture is increased? Explain.
  1m 10s

• 8.    The diagram below is a sketch of the graph of non catalysed decomposition of hydrogen peroxide. On the same axis, sketch the graph for decomposition of hydrogen peroxide when manganese (IV) oxide is added.
  2m 20s

• 9.    The figure below shows an energy cycle (a) Give the name of the enthalpy change #H_1# (b) Determine the value of #H_3#
  1m 39s

• 10.    The following reaction is in equilibrium in a closed container #C(s)+H_2O(g)overset(leftarrow)(rightarrow)CO(g)+H_2# State giving reasons how an increase in pressure would affect the amount of hydrogen.
  0m 57s

• 11.    In a closed system, aqueous iron (III) chloride reacts withhydrogen sulphide gas as shown in the equation below. #2FeCl_3(aq)+H_2S(g)overset(rightarrow)(leftarrow)2FeCl_2(aq)+2HCl(aq)+S(s)# State and explain the observation that would be made if dilute hydrochloric acid is added the system at equilibrium.
  1m 35s

• 12.    Nitrogen and hydrogen react to form ammonia gas as shown in the following equation:# N_2(g)+3H_2(g)?2NH_3(g)#; H is negative (a) The figure below shows how the percentage of ammonia gas in the equilibrium mixture changes with temperature. Explain why the percentage of ammonia gas changes as shown in the figure. (b) On the axis below, sketch a graph showing how the percentage of ammonia gas in
  1m 59s

• 13.    Ethanoic acid and ethanol react as shown in the equation below: Other than warming, how would the state of equilibrium be established within a short time?
  0m 34s

• 14.    (a) Ethanol can be manufactured from ethene and steam as shown in the equation below: Temperature and pressure will affect the position of equilibrium of the above reaction. Name the other factor that will affect the position of equilibrium of the above reaction. (b) The data in the table below was recorded when one mole of ethene was reacted with excess steam. The amount of ethanol in the
  2m 6s

• 15.    The curves below represent the change in mass when equal masses of powdered zinc and zinc granules were reacted with excess 2M hydrochloric acid. Study them and answer the question below. Which curve represents the reaction with zinc granules? Explain your answer.
  1m 13s

• 16.    In an experiment on rates of reaction, potassium carbonate was reacted with dilute sulphuric (VI) acid. (a) What would be the effect of an increase in the concentration of the acid on the rate of the reaction? (b) Explain Why the rate of reaction is found to increase with temperature.
  0m 58s

• 17.    The curve shown below shows the variation of time against temperature for the reaction between sodium thiosulphate and hydrochloric acid. (a) Write the equation for the reaction between sodium thiosulphate and dilute hydrochloric acid. (b) Explain the shape of the curve.
  2m 0s

• 18.    (a) Other than concentration, state two factors that determine the rate of a reaction. (b) In an experiment to determine the rate of reaction, excess lambs of calcium carbonate were added to 2 M hydrochloric acid. The mass of calcium carbonate left was recorded after every 30 seconds. The results are shown in the table below. Write the equation for the reaction that took place.
  1m 55s

• 19.    In an experiment on rates of reaction, potassium carbonate was reacted with dilute sulphuric (VI) acid. What would be the effect of an increase in the concentration of the acid on the rate of the reaction?
  0m 36s

• 20.    (a) Methanol is manufactured from carbon (IV) oxide and hydrogen gas according to the equation: #CO_2# (g) + #3H_2#(g)#rightarrow# #CH_3OH#(g) + #H_2O#(g) The reaction is carried out in the presence of a chromium catalyst at 700K and 30kPa. Under these conditions, equilibrium is reached when 2% of the carbon (IV) oxide is converted to methanol (i)How does the rate of the forward reaction compare
  5m 4s

• 21.    (a) State one characteristic of a reaction where equilibrium has been attained. (b) The following equation is in a state of equilibrium: C#overset(rightarrow)(leftarrow)# D Use it to sketch a graphical representation of concentration against time in seconds for the equilibrium.
  1m 19s

• 22.    Describe how an increase in concentration increases the rate of a reaction.
  0m 26s

• 23.    (a) What is meant by rate of reaction? (b) In the space provided, Sketch the diagram of a set-up that Can be used to determine the rate of reaction between manganese(IV) oxide and hydrogen peroxide.
  2m 19s

• 24.    The curves shown below were obtained when two equal volumes of hydrogen peroxide of the same concentration were allowed to decompose separately. In one case, manganese (IV) oxide was added to the hydrogen peroxide. Which curve represents the decomposition of hydrogen peroxide with manganese (IV) oxide? Explain.
  1m 10s

• 25.    In an experiment, 0.8g of magnesium powder were reacted with excess dilute sulphuric (VI) acid at #25^(0)#C. The time for the reaction to come to completion was recorded. The experiment was repeated at #40^(0)#C. In which experiment was the time taken shorter? Explain your answer.
  0m 59s

• 26.    State and explain how the rate of reaction between zinc granules and steam can be increased.
  0m 19s

• 27.    Bismuth chloride# (BiCL_3)# reacts with water according to the equation given below. a) State what would happen when a few drops of dilute hydrochloric acid are added to the mixture at equilibrium. b) Give a reason for your answer in (a) above.
  0m 44s

• 28.    The reaction between a piece of magnesium ribbon with excess 2M hydrochloric acid was investigated at #25^(0)#C by measuring the volume of hydrogen gas produced as the reaction progressed. The Sketch below represents the graph that was obtained. (a) Name one piece of apparatus that may be used to measure the volume of hydrogen gas produced. (b) On the same diagram, sketch the curve that would be
  1m 17s

• 29.    The sketch shows how substances H is converted into J. study it and answer the question that follows. Why do the two curves become horizontal after sometime?
  0m 48s

• 30.    a) What condition is necessary for equilibrium to be established? b) When calcium carbonate is heated, the equilibrium shown below is established #CaCO_3(s) overset(rightarrow)(leftarrow) CaO(s) + C0_2#(g) How would the position of equilibrium be affected if a small amount of dilute potassium hydroxide is added to the equilibrium mixture? Explain.
  1m 37s

• 31.    At #20^(0)#C, #NO_2 and N_2O_4# gases exist in equilibrium as shown in the equation below. #2NO_2(g) overset(rightarrow)(leftarrow) N_2O_4(g)# ; = -ve Brown Pale yellow State and explain the observation that would be made when ; (a) A syringe containing the mixture at #20^(0)#C is immersed in ice-cold water. (b) The volume of the gaseous mixture in a syringe is reduced.
  1m 44s

• 32.    (a) The figure below shows how the rate of the following reaction varies with time. A(g) + B(g) #overset(rightarrow)(leftarrow)# 2C(g) + D(g) i. Which of the two curves represents the rate of the reverse reaction? Give a reason. ii. What is the significance of points X and Y on the figure? (b) State and explain the effect of an increase in pressure on the
  2m 19s