Biology Forums - Study Force

A vessel containing 10 kg of water is left out where it evaporates. If the temperature remains constant at 20C, what is the change in entropy (in kcal/K)? (The latent heat of vaporization at 20C is 585 cal/g.)
 a. 30
  b. 10
  c. 20
  d. 40
  e. 290

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[Ques. 2] Find the change in entropy (in J/K) when 5.00 moles of an ideal monatomic gas are allowed to expand isobarically from an initial volume of 20 cm3 to a final volume of 100 cm3.
 a. 167
  b. 100
  c. 67
  d. 52
  e. 152

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[Ques. 3] Ten kilograms of water at 0C is mixed with 10 kg of water at 100C. What is the change in entropy (in cal/K) of the system?
 a. 1000
  b. 480
  c. 720
  d. 240
  e. 168

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[Ques. 4] An ideal gas is allowed to expand adiabatically. Assume the process is reversible. What is the change in entropy?
 a. 0
  b. nR ln (V2/V1)
  c. nR ln (T2/T1)
  d. kn ln (V2/V1)
  e. kn ln (T2/T1)

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[Ques. 5] Find the change in entropy (in J/K) when 5.00 moles of an ideal gas undergo a free expansion from an initial volume of 20 cm3 to a final volume of 100 cm3.
 a. 71
  b. 52
  c. 67
  d. 191
  e. 208

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[Ques. 6] An ideal gas is allowed to undergo a free expansion. If its initial volume is V1 and its final volume is V2, the change in entropy is
 a. nR ln (V2/V1)
  b. nRT ln (V2/V1)
  c. nk ln (V2/V1)
  d. 0
  e. nR V2/V1

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[Ques. 7] Determine the change in entropy (in J/K) when 5.00 moles of an ideal gas at 0C are compressed isothermally from an initial volume of 100 cm3 to a final volume of 20 cm3.
 a. 191
  b. 52
  c. 71
  d. 67
  e. 208

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[Ques. 8] Since LF,ice = 333 J/g, what is the change in entropy (in cal/K) when 1.00 kg of ice melts?
 a. 144
  b. 291
  c. 312
  d. 516
  e. 80

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[Ques. 9] The change in entropy of a mass m of a solid substance which has a latent heat of fusion LF and melts at a temperature T is
 a. LFT/m
  b. mLF ln(T)
  c. mLFT
  d. mLF/T
  e. LF/mT

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[Ques. 10] When water of mass m and specific heat c is heated at constant pressure from absolute temperature T1 to absolute temperature T2, its change in entropy is what?
 a. cm ln(T2/T1)
  b. cm (T2/T1)
  c. cm (T2  T1)/T1
  d. cm (T2  T1)/T2
  e. cm (T2  T1)/(T2 + T1)

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