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?

  • ACompression of the reaction mixture
  • BThe presence of a catalyst
  • CHeating of the reaction mixture
  • DRecycling of reactants
  • EDrying of the reaction mixture

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 prevent the formation of unwanted side products
  • CTo prevent degradation of the catalyst
  • DTo increase the reaction yield
  • ETo increase the reaction rate

Q4:

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

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

Q5:

A sample of nitrogen is reacted with excess hydrogen to produce 2.80 tonnes 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 ( C H ) 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 + 4 H 4 2 2 2
  • B C H + H O C O + 2 H 4 2 2
  • C C H + 2 H O C O + 8 H 4 2 2 2
  • D C H + H O C O + 3 H 4 2 2
  • E C H + 2 H O 2 C O + 4 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 and percentage yield both decrease.
  • CThe reaction rate and percentage yield both increase.
  • DThe reaction rate decreases and the percentage yield increases.
  • EThe reaction rate increases and the percentage yield is approximately constant.

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 2 C O + 4 H O 2 H C O + 3 H 2 3 2
  • B C O + 2 H O C O + 2 H 2 3 2
  • C C O + H O C O + H 2 2 2
  • D C O + H O C + O + H 2 2 2
  • E C O + 2 H O H C O + H 2 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 is approximately constant.
  • BThe reaction rate increases and the percentage yield decreases.
  • CThe reaction rate decreases and the percentage yield increases.
  • DThe reaction rate and percentage yield both decrease.
  • 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?

  • AReduced reaction rate
  • BReduced maximum percentage yield
  • CIncreased formation of unwanted side products
  • DIncreased equipment and running costs
  • ECondensation of the gaseous reactants

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
  • BReduced reaction rate
  • CMelting of the solid catalyst
  • DReduced maximum percentage yield
  • EIncreased equipment and running costs

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?

  • AOxygen and carbon dioxide
  • BCarbon dioxide and water
  • CWater and argon
  • DOxygen and argon
  • EOxygen and water

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

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

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

  • AThe product of the reaction is removed as it forms, preventing it from converting back to the original 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 products of the reaction are much more stable than the reactants.
  • EThe reaction is highly exothermic.

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

  • ACooling and drying
  • BFiltering and distilling
  • CHeating and distilling
  • DCooling and distilling
  • EHeating and filtering

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 2 N H 2 2 2
  • C N + 4 H 2 N H 2 2 4
  • D N + 3 H 2 N H 2 2 3
  • E N + 2 H N H 2 2 2 4

Why is this reaction described as reversible?

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

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

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 increases.
  • BThe reaction rate increases and the percentage yield decreases.
  • CThe reaction rate decreases and the percentage yield remains approximately constant.
  • 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?

  • APlatinum
  • BNickel
  • CVanadium
  • DIron
  • 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.

  • ACatalyst surface area in square meters per gram
  • BTemperature in kelvins
  • CTemperature in celsius
  • DPressure in atmospheres
  • EPressure in Pascals

Identify the variable 𝑌 .

  • ATemperature in celsius
  • BPressure in Pascals
  • CPressure in atmospheres
  • DTemperature in kelvins
  • ECatalyst surface area in square meters per gram

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