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Carbon monoxide and hydrogen can be produced from the reaction of methane with steam according to the equation $$CH_4(g) + H_2O(g) ⇌ CO(g) + 3H_2(g); \, ΔH = +206 \, kJ \, mol^{-1}$$ Some methane and steam are placed in a closed container and allowed to react at a fixed temperature - VCE - SSCE Chemistry - Question 1 - 2007 - Paper 1
Question 1
Carbon monoxide and hydrogen can be produced from the reaction of methane with steam according to the equation $$CH_4(g) + H_2O(g) ⇌ CO(g) + 3H_2(g); \, ΔH = +206 \... show full transcript
Worked Solution & Example Answer:Carbon monoxide and hydrogen can be produced from the reaction of methane with steam according to the equation $$CH_4(g) + H_2O(g) ⇌ CO(g) + 3H_2(g); \, ΔH = +206 \, kJ \, mol^{-1}$$ Some methane and steam are placed in a closed container and allowed to react at a fixed temperature - VCE - SSCE Chemistry - Question 1 - 2007 - Paper 1
Step 1
a. i. On the graph above, draw a line to show the change in concentration of hydrogen gas as the reaction progresses. Label this line.
Answer
To indicate the change in concentration of hydrogen gas (H₂) over time, I will draw a line starting at zero concentration and increasing as the reaction progresses, eventually leveling off as equilibrium is approached. This line will be labeled as H₂.
Step 2
a. ii. On the graph above, draw a line to show the formation of carbon monoxide would differ over time in the presence of a catalyst. Label this line.
Answer
In the presence of a catalyst, the reaction rate for the formation of carbon monoxide (CO) would increase. Therefore, I will draw a steeper line from the starting point to indicate a faster increase in concentration compared to the line without a catalyst. This will be labeled as CO with catalyst.
Step 3
b. What does the above information indicate about the magnitude of the equilibrium constant K₁ compared with the magnitude of the equilibrium constant K₂?
Answer
The information suggests that the equilibrium constant K₂ for the reaction involving carbon monoxide is likely to be smaller than K₁. This is because carbon monoxide competes with oxygen for binding to haemoglobin, indicating that the formation of carbon monoxide-haemoglobin complex is favored under these conditions, thus reducing the concentration of haemoglobin available for binding with oxygen.
Step 4
c. Indicate whether the following statements about rates in the collision theory model are true or false.
Answer
| Statement | True | False |
|---|---|---|
| i. Endothermic reactions are always slower than exothermic reactions. | ☐ | ☑ |
| ii. All particles have the same kinetic energy at a fixed temperature. | ☐ | ☑ |
| iii. Reactant particles collide in order to react. | ☑ | ☐ |
| iv. The rate of reaction at a constant temperature increases as the surface area of the reactants increases. | ☑ | ☐ |
| v. Temperature increases the fraction of collisions with energy. | ☑ | ☐ |