Worksheet: The Second Law of Thermodynamics
In this worksheet, we will practice defining the second law of thermodynamics, which states that the entropy of the universe must increase.
Which of the following represents a necessary condition for a chemical reaction to proceed from reactants to products spontaneously?
- AThe reaction must be exothermic.
- BThe total entropy of the reacting chemical system and its surroundings must increase.
- CThe reaction must be endothermic.
- DThe standard entropy change, , for the chemical reaction must be ≥ 0.
Which of the following played a significant role in developing the concept of entropy and in formulating the second law of thermodynamics?
- AThe Nernst heat theorem
- BThe equipartition of energy principle
- CThe Heisenberg uncertainty principle
- DThe formulation and analysis of the Carnot cycle and heat engine
Which of the following statements does not conform to the laws of thermodynamics?
- AThe entropy of any chemically pure substance approaches a value of zero as the temperature of the substance approaches a value of 0 K and at and .
- BThe entropy of a system always decreases with a decrease in the temperature of the system.
- CThe entropy of the universe always increases in a spontaneous change of state process.
- DThe energy of the universe always remains constant in any change of state process.
Why is it difficult to predict whether the entropy change in the complete combustion of methane will be positive or negative?
- AThe products of the reaction vary depending on the oxygen concentration.
- BThe reactants and products can all be modeled as ideal gases.
- CThe reaction does not change the number of covalent bonds.
- DHeat released by the reaction may reverse the sign of the entropy change.
- EThe reaction does not change the number of gaseous molecules.
The boiling of water is represented by the equation The standard molar entropy of a material, , is the molar entropy of the material at 298 K and 1.00 bar pressure. The value of for liquid water is 70.0 J/mol⋅K and the value for steam is 188.8 J/mol⋅K. Calculate , the standard molar entropy change for boiling water.