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First Law of Thermodynamics · CAPE Physics Unit 1

59 past-paper questions on First Law of Thermodynamics, part of Thermal and Mechanical Properties of Matter, from every CAPE Physics Unit 1 paper on Quelpr.

Practise First Law of Thermodynamics
  1. Q341 mark · multiple choice· CAPE Physics Unit 1 · 2007 · Paper 116 \times 10^{-3}\text{ m}^3 of a gas at a pressure of 1750\text{ kPa} is contained in a cylinder. The gas is expanded at constant pressure until the volume becomes 140 \times 10^{-3}\text{ m}^3. How much work is…
  2. Q391 mark · multiple choice· CAPE Physics Unit 1 · 2007 (Specimen) · Paper 1The above P-V diagram represents a gas being taken through three processes, 1 to 2, 2 to 3 and 3 to 1 to complete the cycle. In which process(es) is work being done ON the gas?
  3. Q401 mark · multiple choice· CAPE Physics Unit 1 · 2008 (Rest of Region) · Paper 1A boiler contains water at atmospheric pressure. Use the data below to calculate the work done by the system in producing 1\text{ kg} of steam (water vapour) at atmospheric pressure. Data: 1\text{ kg} of water at…
  4. Q411 mark · multiple choice· CAPE Physics Unit 1 · 2008 (Rest of Region) · Paper 1Which of the following statements about an isothermal process in an ideal gas are true? I. The energy added by heating, Q, is zero II. The change in internal energy, \Delta U, is zero III. The work done by the gas,…
  5. Q411 mark · multiple choice· CAPE Physics Unit 1 · 2009 · Paper 1The first law of thermodynamics may be written as \Delta U = Q + W. For an isothermal process this equation becomes
  6. Q361 mark · multiple choice· CAPE Physics Unit 1 · 2011 · Paper 1Gas in an enclosed system is allowed to expand with no thermal energy entering or leaving the system. Which of the following statements is true?
  7. 3(c)3 marks· CAPE Physics Unit 1 · May/June 2024 · Paper 2The first law of thermodynamics is given by ΔU = Q + W. Explain the meaning of EACH symbol when applied to the heating of a fixed mass of gas.
  8. 3(d)(i)2 marks· CAPE Physics Unit 1 · May/June 2024 · Paper 2Calculate the work done during the cycle.
  9. 3(d)(iii)4 marks· CAPE Physics Unit 1 · May/June 2024 · Paper 2Calculate the energy added as heat during the process from State 1 to State 2.
  10. 3(d)(iv)2 marks· CAPE Physics Unit 1 · May/June 2024 · Paper 2Derive an expression for Cₚ for the gas in terms of R.
  11. 3(a)2 marks· Physics · Unit 1 Q3 3(a)Write an equation to represent the first law of thermodynamics. State the meaning of EACH symbol used.
  12. 3(a)2 marks· Physics · Unit 1 Q3 3(a)Write an equation representing the First Law of Thermodynamics and state the meaning of EACH symbol used.
  13. 3(b)(i)4 marks· Physics · Unit 1 Q3 3(b)(i)On the grid provided in Figure 4 (page 13), plot a graph of pressure, P, against volume, V.
  14. 3(b)(i)4 marks· Physics · Unit 1 Q3 3(b)(i)On the grid provided on page 11, plot a graph of pressure, P, against volume, V.
  15. 3(b)(ii)3 marks· Physics · Unit 1 Q3 3(b)(ii)Use the graph, to determine the work done by the gas during expansion.
  16. 3(b)(ii)3 marks· Physics · Unit 1 Q3 3(b)(ii)Use your graph to determine the work done by the gas during the expansion.
  17. 3(b)(v)2 marks· Physics · Unit 1 Q3 3(b)(v)Determine the quantity of heat that is absorbed by the gas during expansion.
  18. 3(b)(v)2 marks· Physics · Unit 1 Q3 3(b)(v)Determine the heat supplied to the gas during the expansion.
  19. 3(d)(i)4 marks· Physics · Unit 1 Q3 3(d)(i)Using the information given in Table 3 on page 20, sketch a P-V graph of the gas engine cycle, clearly labelling EACH stage and its corresponding pressure and volume.
  20. 3(d)(iii)3 marks· Physics · Unit 1 Q3 3(d)(iii)Determine the heat energy supplied to the gas in going from Stage A to Stage B.
  21. 3(e)3 marks· Physics · Unit 1 Q3 3(e)Use the graph to determine the work done in this expansion.
  22. 3(f)4 marks· Physics · Unit 1 Q3 3(f)State the first law of thermodynamics, clearly defining EACH term.
  23. 3(g)2 marks· Physics · Unit 1 Q3 3(g)With reference to the first law of thermodynamics, calculate the change in internal energy of the gas in the engine as it goes from Stage B to Stage C.
  24. 6(a)1 mark· Physics · Unit 1 Q6 6(a)The first law of thermodynamics is given by the equation ΔU = Q + W.
  25. 6(a)(i)6 marks· Physics · Unit 1 Q6 6(a)(i)Write down an equation for the First Law of Thermodynamics clearly explaining the meaning of the symbols used.
  26. 6(a)(i)6 marks· Physics · Unit 1 Q6 6(a)(i)Explain the meaning of EACH of the terms used in the equation when the law is applied to the heating of a fixed mass of gas.
  27. 6(a)(ii)6 marks· Physics · Unit 1 Q6 6(a)(ii)Explain why the heat capacity of a gas at constant pressure, Cp, is greater than the heat capacity of the gas at constant volume, Cv. Write down an expression that relates the two quantities with the Universal Gas…
  28. 6(a)(ii)1 mark· Physics · Unit 1 Q6 6(a)(ii)Use the first law of thermodynamics to explain why the molar heat capacity at constant pressure, Cₚ, is greater than the molar heat capacity at constant volume, Cᵥ.
  29. 6(b)(i)3 marks· Physics · Unit 1 Q6 6(b)(i)Explain this rise in temperature on a macroscopic scale, using the first law of thermodynamics.
  30. 6(b)(i)3 marks· Physics · Unit 1 Q6 6(b)(i)Explain this rise in temperature on a macroscopic scale, using the first law of thermodynamics.
  31. 6(b)(i)9 marks· Physics · Unit 1 Q6 6(b)(i)the work done during the cycle
  32. 6(b)(ii)a)2 marks· Physics · Unit 1 Q6 6(b)(ii)a)Using data from the graph, calculate the quantity of heat required to take the gas from C to A along CA.
  33. 6(b)(ii)b)2 marks· Physics · Unit 1 Q6 6(b)(ii)b)Using data from the graph, calculate the quantity of heat required to take the gas from C to B along CB.
  34. 6(b)(iii)2 marks· Physics · Unit 1 Q6 6(b)(iii)Using data from the graph, calculate the work done by the gas along the path from C to B.
  35. 6(b)(iii)1 mark· Physics · Unit 1 Q6 6(b)(iii)the energy added as heat during the processes 1 → 2 and 2 → 3
  36. 6(b)(iv)1 mark· Physics · Unit 1 Q6 6(b)(iv)the efficiency of the cycle.
  37. 6(d)1 mark· Physics · Unit 1 Q6 6(d)The work done on the gas during the compression is 90 J. Use the first law of thermodynamics to find the increase in the internal energy of the gas during the compression.
  38. 6(d)1 mark· Physics · Unit 1 Q6 6(d)The work done on the gas during the compression is 85 J. Use the first law of thermodynamics to determine the INCREASE in the thermal energy of the gas during the compression.
  39. 6(e)3 marks· Physics · Unit 1 Q6 6(e)Determine its molar heat capacity, C_v.
  40. 6(e)3 marks· Physics · Unit 1 Q6 6(e)Calculate the molar heat capacity of the gas in the container.
  41. 8(b)(i)9 marks· Physics · Unit 1 Q8 8(b)(i)Calculate an estimate for the change of internal energy of the gas at C.
  42. 8(b)(i)12 marks· Physics · Unit 1 Q8 8(b)(i)Calculate the thermal energy supplied to the gas.
  43. 8(b)(ii)9 marks· Physics · Unit 1 Q8 8(b)(ii)Why is the actual value for the change of internal energy of the gas at C lower than the value you calculated in (b)(i) above.
  44. 8(b)(iii)1 mark· Physics · Unit 1 Q8 8(b)(iii)Calculate the work done by the gas as it expands.
  45. 8(c)(ii)1 mark· Physics · Unit 1 Q8 8(c)(ii)Find the molar heat capacity at constant volume for oxygen. (Molar heat capacity at constant pressure = 29 J mol⁻¹ K⁻¹)
  46. 9(a)(i)8 marks· Physics · Unit 1 Q9 9(a)(i)State the first law of thermodynamics in the form of an equation and explain the symbols used.
  47. 9(a)(iii)1 mark· Physics · Unit 1 Q9 9(a)(iii)The molar heat capacity of a gas at constant pressure, cₚ, differs from the molar heat capacity at constant volume, cᵥ. State which is the GREATER and explain why.
  48. 9(b)1 mark· Physics · Unit 1 Q9 9(b)Calculate:
  49. 9(b)(i)12 marks· Physics · Unit 1 Q9 9(b)(i)Draw a graph to represent these changes.
  50. 9(b)(i)2 marks· Physics · Unit 1 Q9 9(b)(i)Write an equation representing the first law of thermodynamics and state CLEARLY the meaning of EACH term.
  51. 9(b)(ii)1 mark· Physics · Unit 1 Q9 9(b)(ii)Show that the OVERALL change of internal energy is given by ΔU = (33/2) P₀V₀.
  52. 9(b)(ii)3 marks· Physics · Unit 1 Q9 9(b)(ii)How much thermal energy would be required to raise the temperature of 6.2 mol of a gas from 25°C to 50°C while the volume remained constant if C_v = 12.5 J K⁻¹ mol⁻¹?
  53. 9(b)(iii)12 marks· Physics · Unit 1 Q9 9(b)(iii)the work done by the gas in the expansion.
  54. 9(b)(iii)a)1 mark· Physics · Unit 1 Q9 9(b)(iii)a)Calculate the work done by the gas on the surroundings.
  55. 9(b)(iii)b)1 mark· Physics · Unit 1 Q9 9(b)(iii)b)Calculate the thermal energy added to the gas.
  56. 9(b)(iv)2 marks· Physics · Unit 1 Q9 9(b)(iv)If instead, the gas were heated at constant pressure from 25°C to 50°C the thermal energy required would be 3200 J. How much work would be done by the gas in this case?
  57. 9(b)(iv)12 marks· Physics · Unit 1 Q9 9(b)(iv)the change in the internal energy of the gas during the expansion.
  58. 9(b)(v)2 marks· Physics · Unit 1 Q9 9(b)(v)Deduce the value of C_p, the molar heat capacity of the gas, at constant pressure.
  59. 9(b)(v)12 marks· Physics · Unit 1 Q9 9(b)(v)the heat added to the gas.

Related topics in Thermal and Mechanical Properties of Matter