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2002 - Q13

 

The Haber Process for producing ammonia was developed early in the twentieth century.

What was the major advantage of its development?

 

(A) A government sold the process to other governments

(B) The inventor sold the process for a great deal of money

(C) It provided a source of nitrogen for farming and industry

(D) It provided jobs for many who were unemployed

2002 - Q14

 

Ammonia is produced from hydrogen and nitrogen, according to the equation:

 

 

 

 

 

 

 

 

 

 

 

 

Which graph shows a correct comparison of the yield of ammonia produced at a temperature of 400'C and 100 kPa with the yield produced at 200'C and 100 kPa?

2004 - Q10

 

Phosgene is prepared from the reaction of carbon monoxide and chlorine in the presence of a catalyst:

 

CO(g) + Cl2(g) ----> COCl2(g) ∆H = − 9.93 kJ/mol

 

Which of the following sets of conditions would produce the highest yield of phosgene?

 

(A) High temperature, high pressure

(B) Low temperature, low pressure

(C) Low temperature, high pressure

(D) High temperature, low pressure

2001 - Q24 (6 marks)

 

In the early twentieth century, Fritz Haber developed a method for producing ammonia, as shown by the equation:

 

                                       N2 (g) + 3H2 (g)  <---> 2NH3 (g)

 

(a) Ammonia is used as a cleaning agent. State ONE other use of ammonia. (1 mark)

 

(b) Explain the effect of liquefying the ammonia on the yield of the reaction (2 marks)

 

(c) Explain why it is essential to monitor the temperature and pressure inside the reaction vessel. (3 marks)

2003 - Q29 (7 marks)

 

Evaluate the importance of monitoring and managing the conditions used in the Haber process.

2005 - Q27 (5 marks)

 

The graph shows the variation in concentrations of reactants and product with time for the Haber process.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(a) State why the concentrations of reactants and product do not change between T1 and T2. (1 mark)

 

(b) At time T2 the volume of the reaction vessel was reduced.

 

(i) Sketch on the graph how the concentrations of reactants and product would change after the volume was reduced. (2 marks)

 

(ii) Explain the changes shown on your graph. (2 marks)

2006 - Q24 (5 marks)

 

Early in the twentieth century, Fritz Haber developed a method for preparing ammonia.

 

(a) Write a balanced chemical equation for the preparation of ammonia using the Haber process. (1 mark)

 

(b) Evaluate the significance of Haber’s discovery at that time in world history. (4 marks)

2005 - Q7

 

A series of observations was made about a first-hand investigation.

• A cup of carbonated soft drink was poured from a newly-opened, chilled bottle.

• A lot of bubbles were observed in the cup.

• The cup was then left on the kitchen bench for several hours.

• After this time, it was observed that there were no bubbles visible in the cup.

 

Why were there no bubbles visible in the cup after several hours?

 

(A) The bubbles of carbon dioxide had dissolved into the soft drink.

(B) The carbon dioxide had been neutralised by the water in the soft drink.

(C) Carbon dioxide is less soluble at higher temperatures and lower pressures.

(D) Carbon dioxide is more soluble at higher temperatures and lower pressures.

2006 - Q12

 

Which statement explains why catalysts are often used in chemical reactions?

 

(A) Catalysts increase the rate of reactions.

(B) Catalysts increase the yield of products of reactions. (C) Catalysts increase the purity of products of reactions. (D) Catalysts increase the activation energies of reactions.

2007 - Q13

 

Consider the following reaction at equilibrium.

 

      N2 (g) + 3H2 (g)  <---> 2NH3 (g)     ΔH = –92 kJ mol–1

 

What would be the effect of a decrease in pressure on this system?

 

(A) Heat will be absorbed.

(B) The equilibrium will not be disturbed.

(C) The concentration of NH3 will increase.

(D) The reverse rate of reaction will decrease.

2010 - Q9

 

What types of reaction occur in the Haber process during the production of ammonia?

 

(A) Redox and synthesis

(B) Hydration and redox

(C) Decomposition and oxidation

(D) Reduction and decomposition

2008 - Q23 (4 marks)

 

Using Le Chatelier’s principle, justify the choice of temperature and pressure conditions used to optimise the yield in the Haber process.

2009 - Q23 (6 marks)

 

The graph shows the variation in concentration of reactant and products as a function of time for the following system.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Identify and explain each of the changes in conditions that have shaped the curves during the time the system was observed.

2011 - Q30 (6 marks)

 

The flowchart outlines the sequence of steps in the Ostwald process for the manufacture of nitric acid.

 

 

 

 

 

 

 

 

 

 

 

 

Explain the reaction conditions required at each step of the Ostwald process to maximise the yield and production rate of nitric acid.

2010 - Q18

 

Chromate and dichromate ions form an equilibrium according to the following equation.

 

2CrO4 2− (aq) + 2H+ (aq) <---->  Cr2O7 2− (aq) + H2O(l)

 

Which solution would increase the concentration of the chromate ion   (CrO4 2− ) when added to the equilibrium mixture?

 

(A) Sodium nitrate

(B) Sodium chloride

(C) Sodium acetate

(D) Ammonium chloride

2012 - Q24 (3 marks)

 

Explain why ammonia is such an important raw material in industry today.

2013 - Q24 (4 marks)

 

Consider this chemical system which is at equilibrium.

 

                                              X(g) + Y(g)  <---->  Z(g) + heat

 

(a) Explain the effect of decreasing the volume of the reaction vessel. (2 marks)

 

(b) Explain the effect of adding a catalyst to this equilibrium mixture. (2 marks)

2012 - Q3

 

What effect does a catalyst have on a reaction?

 

(A) It increases the rate.

(B) It increases the yield.

(C) It increases the heat of reaction.

(D) It increases the activation energy.

2013 - Q1

 

Which pair of reactants is used to industrially synthesise ammonia?

 

(A) H2 and C

(B) H2 and N2

(C) H2O and N2

(D) H2O and NO2

2013 - Q10

 

The following equilibrium is set up in a sealed reaction vessel.

 

                                  N2O4(g) <----> 2NO2(g)       ΔH = +54.8 kJ mol–1

 

Which of the following would INCREASE the yield of nitrogen dioxide?

 

(A) Adding a catalyst to the reaction vessel

(B) Decreasing the volume of the reaction vessel

(C) Raising the temperature of the reaction vessel

(D) Increasing the pressure by adding argon to the reaction vessel

2015 - Q30 (6 marks)

 

The graph shows the percentage yield of ammonia produced from nitrogen and hydrogen at different temperatures and pressures.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Haber process is the main industrial procedure for the production of ammonia.

 

Explain the conditions used in the Haber process with reference to the graph.

2014 - Q13

 

This equation shows an equilibrium established in the synthesis of ammonia from its component gases:

 

                                 N2(g) + 3H2(g) <----> 2NH3(g)

 

If the volume of the reaction chamber is suddenly halved at time T, which of the following best depicts changes in the concentration of ammonia over time?

2014 - Q20

 

This graph represents the yield of an equilibrium reaction at different temperature and pressure conditions inside a reaction vessel.

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