Worksheet: The Haber Process

In this worksheet, we will practice describing the reaction of nitrogen and hydrogen in the Haber process and explaining the choices of reaction conditions.

Q1:

The reaction of 381.2 kg of nitrogen with 86.1 kg of hydrogen in the Haber process results in a yield of 75.0%. Calculate the mass of product in this reaction.

Q2:

Which feature of a typical reactor in the Haber process allows very high maximum percentage yields to be achieved?

  • ADrying of the reaction mixture
  • BRecycling of reactants
  • CCompression of the reaction mixture
  • DHeating of the reaction mixture
  • EThe presence of a catalyst

Q3:

What is the main reason for removing the product from the reaction mixture during the Haber process?

  • ATo lower the pressure of the reaction mixture
  • BTo increase the reaction yield
  • CTo prevent degradation of the catalyst
  • DTo increase the reaction rate
  • ETo prevent the formation of unwanted side products

Q4:

Which of the following changes could lower the reaction rate in the Haber process?

  • AIncreasing the pressure of the reaction mixture
  • BIncreasing the reaction temperature
  • CIncreasing the mass of the catalyst
  • DIncreasing the flow rate over the catalyst
  • EReducing the size of catalyst particles

Q5:

A sample of nitrogen is reacted with excess hydrogen to produce 2.80 metric tons of product via the Haber process. The yield of the reaction is 41.0%. Calculate the mass of the nitrogen sample.

Q6:

The Haber process is a gas-phase reaction involving hydrogen gas (H)2. A major source of hydrogen gas is the reaction of methane (CH)4 with steam. This process is known as steam reforming.

Give a balanced chemical equation for the steam reforming of methane gas, which generates carbon monoxide as a gaseous by-product.

  • A C H + 2 H O C O + 8 H 4 2 2 2
  • B C H + H O C O + 2 H 4 2 2
  • C C H + 2 H O 2 C O + 4 H 4 2 2
  • D C H + 2 H O C O + 4 H 4 2 2 2
  • E C H + H O C O + 3 H 4 2 2

Steam reforming involves a reversible reaction. How do the reaction rate and percentage yield change if the pressure of the reacting gases is increased?

  • AThe reaction rate increases and the percentage yield decreases.
  • BThe reaction rate increases and the percentage yield is approximately constant.
  • CThe reaction rate and percentage yield both increase.
  • DThe reaction rate and percentage yield both decrease.
  • EThe reaction rate decreases and the percentage yield increases.

Additional hydrogen can be produced by reacting carbon monoxide from steam reforming with additional water, in a process known as the water-gas shift reaction. There is only one other product. Give a balanced chemical equation for this reaction.

  • A C O + 2 H O C O + 2 H 2 3 2
  • B C O + H O C O + H 2 2 2
  • C C O + 2 H O H C O + H 2 2 3 2
  • D C O + H O C + O + H 2 2 2
  • E 2 C O + 4 H O 2 H C O + 3 H 2 3 2

The water-gas shift reaction is reversible. How do the reaction rate and percentage yield change if the pressure of the reacting gases is increased?

  • AThe reaction rate increases and the percentage yield decreases.
  • BThe reaction rate decreases and the percentage yield increases.
  • CThe reaction rate and percentage yield both decrease.
  • DThe reaction rate increases and the percentage yield is approximately constant.
  • EThe reaction rate and percentage yield both increase.

Q7:

The reaction of 30.0 kg of hydrogen with excess nitrogen generates 93.5 kg of product via the Haber process. Calculate the percentage yield of this reaction.

Q8:

The Haber process involves the reversible reaction of two gaseous reactants. What is the main disadvantage of increasing the pressure at which the reaction is performed?

  • ACondensation of the gaseous reactants
  • BReduced reaction rate
  • CReduced maximum percentage yield
  • DIncreased equipment and running costs
  • EIncreased formation of unwanted side products

Q9:

The Haber process involves the reversible reaction of two gaseous reactants. What is the main disadvantage of increasing the temperature at which the reaction is performed?

  • AIncreased formation of unwanted side products
  • BIncreased equipment and running costs
  • CReduced reaction rate
  • DReduced maximum percentage yield
  • EMelting of the solid catalyst

Q10:

The Haber process is a gas-phase reaction involving nitrogen gas (N)2. Pure nitrogen can be produced by reacting air with hydrogen gas and removing the products.

Besides nitrogen, what are the two most abundant components of dry air?

  • ACarbon dioxide and water
  • BOxygen and argon
  • COxygen and water
  • DOxygen and carbon dioxide
  • EWater and argon

Give a balanced chemical equation for the reaction of air with hydrogen.

  • A N + 3 H 2 N H 2 2 3
  • B N + 2 H 2 N H 2 2 2
  • C N + 3 O + H 2 H N O 2 2 2 3
  • D O + H H O 2 2 2 2
  • E O + 2 H 2 H O 2 2 2

The reaction of air with hydrogen is an example of an irreversible reaction. What is meant by this term?

  • AThe products of the reaction are much more stable than the reactants.
  • BThe products of the reaction can never be converted back to the original reactants under the reaction conditions.
  • CThe amount of product that converts back to the original reactants is very close to zero under the reaction conditions.
  • DThe reaction is highly exothermic.
  • EThe product of the reaction is removed as it forms, preventing it from converting back to the original reactants.

Which method can be used to separate the product of this reaction from the nitrogen gas?

  • AHeating and distilling
  • BCooling and drying
  • CHeating and filtering
  • DFiltering and distilling
  • ECooling and distilling

Q11:

The Haber process involves the reversible reaction of nitrogen and hydrogen.

Give a balanced chemical equation for this reaction.

  • A N + 3 H N H 2 2 2 6
  • B N + 2 H N H 2 2 2 4
  • C N + 4 H 2 N H 2 2 4
  • D N + 3 H 2 N H 2 2 3
  • E N + 2 H 2 N H 2 2 2

Why is this reaction described as reversible?

  • AIt is possible to use a different reaction to convert the product back to the original reactants.
  • BThe product cannot undergo further reactions.
  • CThe product converts slowly back to the original reactants once the reaction is complete.
  • DSome of the product converts back to the original reactants under the reaction conditions.
  • EThe product is less stable than the reactants.

If the reaction is performed at a higher gas pressure, what happens to the reaction rate and percentage yield?

  • AThe reaction rate increases and the percentage yield decreases.
  • BThe reaction rate increases and the percentage yield remains approximately constant.
  • CThe reaction rate decreases and the percentage yield increases.
  • DThe reaction rate and percentage yield both increase.
  • EThe reaction rate and percentage yield both decrease.

If the reaction is performed at a lower temperature, what happens to the reaction rate and percentage yield?

  • AThe reaction rate decreases and the percentage yield remains approximately constant.
  • BThe reaction rate decreases and the percentage yield increases.
  • CThe reaction rate increases and the percentage yield decreases.
  • DThe reaction rate and percentage yield both increase.
  • EThe reaction rate and percentage yield both decrease.

Q12:

The nitrogen molecule has a bond energy of 945 kJ/mol and the hydrogen molecule has a bond energy of 436 kJ/mol. The reaction of nitrogen and hydrogen in the Haber process releases 46 kJ for each mole of product. Calculate the bond energy per mole of bonds in the product molecule.

Q13:

At what temperature, in degrees Celsius, is the reaction of the Haber process typically performed?

Q14:

At what gas pressure, in atmospheres, is the reaction of the Haber process typically performed?

Q15:

Which catalyst is typically used in the Haber process?

  • ANickel
  • BIron
  • CPlatinum
  • DVanadium
  • ECopper

Q16:

Illustrated in the plot is the maximum percentage yield of the Haber process at different values of the variables 𝑋 and 𝑌.

Identify the variable 𝑋 and the units used.

  • APressure in Pascals
  • BTemperature in celsius
  • CTemperature in kelvins
  • DPressure in atmospheres
  • ECatalyst surface area in square meters per gram

Identify the variable 𝑌.

  • APressure in Pascals
  • BPressure in atmospheres
  • CTemperature in kelvins
  • DCatalyst surface area in square meters per gram
  • ETemperature in celsius

Q17:

The diagram below illustrates the movement of reactants and products through a reactor in the Haber process.

What is the main function of chamber A?

  • ATo compress the reaction mixture to the required pressure
  • BTo heat the reaction mixture to the reaction temperature
  • CTo cool the product of the reaction
  • DTo catalyze the conversion of reactants to product
  • ETo remove water from the reaction mixture

What is the main function of chamber B?

  • ATo remove water from the reaction mixture
  • BTo collect the catalyst for washing
  • CTo cool the product of the reaction
  • DTo catalyze the conversion of reactants to product
  • ETo wash the reaction mixture to remove side products

What is the function of chamber C?

  • ATo wash the reaction mixture to remove side products
  • BTo compress the reaction mixture to the required pressure
  • CTo heat the reaction mixture to the required temperature
  • DTo catalyze the conversion of reactants to products
  • ETo cool the product of the reaction

What is the function of pathway D?

  • ATo return reactants to the reaction mixture
  • BTo remove product from the reaction mixture
  • CTo remove water from chamber A
  • DTo release the pressure in chamber C
  • ETo remove side products from the reaction mixture

Q18:

The reaction of the Haber process is usually performed in the presence of a catalyst.

Which of the following terms best describe the type of catalyst used?

  • AHeterogeneous and liquid
  • BHeterogeneous and solid
  • CHomogeneous and liquid
  • DHeterogeneous and gaseous
  • EHomogeneous and solid

The schematic plot below illustrates changes in the energy of the reaction mixture during the Haber process. Which labeled energy parameter necessitates the use of a catalyst in this reaction?

  • A 𝐸
  • B 𝐸 𝐸
  • C 𝐸 𝐸
  • D 𝐸 𝐸
  • E 𝐸

Which reaction parameters are increased by the presence of a catalyst?

  • AReaction rate and maximum yield
  • BMaximum yield only
  • CReaction rate and product stability
  • DMaximum yield and product stability
  • EReaction rate only

Which feature of the reactants in the Haber process is the most important in determining the effectiveness of a catalyst?

  • AThe bond energy of the product
  • BThe difference between the bond energies of the reactants and the products
  • CThe difference between the bond energies of hydrogen and nitrogen
  • DThe bond energy of hydrogen
  • EThe bond energy of nitrogen

Q19:

Illustrated in the plot is the product concentration at different times during the Haber process. The reaction is performed in a closed reactor.

Why does the rate of change in concentration decrease between 𝑡 and 𝑡?

  • AThe catalyst is becoming saturated with product molecules.
  • BThe product concentration is approaching the equilibrium value.
  • CThe reactant concentrations are approaching zero.
  • DThe temperature of the reaction mixture is decreasing.
  • EThe pressure of the reaction mixture is decreasing.

At 𝑡, the value of one reaction parameter is changed. What change could be responsible for the observed variation in product concentration?

  • AThe volume is decreased at constant temperature.
  • BThe temperature is increased at constant pressure.
  • CThe volume is decreased at constant pressure.
  • DThe reactant is removed with no change in temperature or pressure.
  • EThe reactant is added with no change in pressure or volume.

Q20:

Samples of nitrogen and hydrogen are reacted together in a closed vessel at a fixed temperature and pressure for time 𝑡. After this time, the volume of the vessel is changed, but the total mass of the reaction mixture does not change.

Which plot best illustrates the change in product concentration over time if the volume is doubled at 𝑡 but the pressure remains constant?

  • A
  • B
  • C
  • D
  • E

Which plot best illustrates the change in product concentration over time if the pressure is doubled at 𝑡 but the temperature remains constant?

  • A
  • B
  • C
  • D
  • E

Illustrated in the plot is the observed variation in product concentration over time. What changes in the reaction parameters at 𝑡 could have produced the observed variation?

  • AThe volume and temperature both increase.
  • BThe temperature increases and the pressure decreases.
  • CThe volume and pressure both increase.
  • DThe volume increases and the temperature decreases.
  • EThe volume decreases and the temperature increases.

Q21:

What is produced by the Haber process?

  • ANitric acid
  • BAmmonia
  • CMargarine
  • DSulfuric acid
  • ESulfur trioxide

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.