When nitrogen and hydrogen react to form ammonia, the reaction can reach a dynamic equilibrium - Edexcel - GCSE Chemistry - Question 4 - 2013 - Paper 1
Question 4
When nitrogen and hydrogen react to form ammonia, the reaction can reach a dynamic equilibrium.
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
(a) Explain what is meant by a dynamic equ... show full transcript
Worked Solution & Example Answer:When nitrogen and hydrogen react to form ammonia, the reaction can reach a dynamic equilibrium - Edexcel - GCSE Chemistry - Question 4 - 2013 - Paper 1
Step 1
Explain what is meant by a dynamic equilibrium.
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Answer
A dynamic equilibrium occurs when the rates of the forward and reverse reactions are equal, leading to no overall change in the concentration of reactants and products. In this state, both the forward and back reactions continue to occur simultaneously, resulting in a stable condition despite ongoing activity.
Step 2
Explain how the use of a higher pressure would affect the equilibrium yield of ammonia.
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Answer
Using a higher pressure would favor the forward reaction in which nitrogen and hydrogen combine to form ammonia, since the reaction produces fewer gas molecules. Specifically, increasing the pressure shifts the equilibrium toward the side with fewer gas moles, thereby increasing the yield of ammonia.
Step 3
Explain how the use of a lower temperature would affect the equilibrium yield of ammonia.
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Answer
A lower temperature would favor the forward reaction because it is exothermic. By shifting the equilibrium to the right, the production of ammonia is maximized as the system compensates for the decrease in temperature by favoring the formation of products.
Step 4
State what is used in industry to overcome this problem.
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In industry, a catalyst, such as iron, is used to speed up the reaction between nitrogen and hydrogen without affecting the equilibrium position.
Step 5
Calculate the minimum volume of hydrogen required to completely convert 1000 dm³ of nitrogen into ammonia.
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Answer
The reaction requires 3 moles of hydrogen for every mole of nitrogen. Therefore, using the stoichiometry:
For 1000 dm³ of nitrogen, the volume of hydrogen needed is:
3imes1000extdm3=3000extdm3
Thus, the minimum volume of hydrogen required is 3000 dm³.
Step 6
Calculate the mass of ammonium nitrate produced by the complete reaction of 34 g of ammonia.
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Using the molar mass calculations:
Molar mass of NH₃ = 14 + (3 imes 1) = 17 g/mol
From 34 g of NH₃, we can calculate the moles:
extMolesofNH3=1734=2extmoles
From the reaction:
1 mole of NH₃ produces 1 mole of NH₄NO₃. Therefore, 2 moles of NH₃ will produce 2 moles of NH₄NO₃.
Molar mass of NH₄NO₃ = 14 + (4 imes 1) + (14) + (3 imes 16) = 80 g/mol
Thus, the mass of NH₄NO₃ produced is:
extMass=2imes80extg=160extg