Interactive Practice on Thermochemistry

Choose the correct answer.

1. Which would have more entropy, water at 273 K or ice at 273 K?
   • water
   • ice
   • both have the same entropy
2. Consider 100. g each of water and an unknown substance. We apply the same amount of heat to each sample. If the unknown substance has a specific heat of 2.4 J/g^oC, which will rise in temperature more? (Specific heat of water = 4.18 J/g^oC)
   • the water will rise in temperature more
   • the unknown substance will rise in temperature more
   • need more information to complete this question
3. A reaction that is always spontaneous...
   • has a positive change in entropy and a positive change in enthalpy
   • has a negative change in entropy and a negative change in enthalpy
   • neither of these
4. Evaporation is
   • always exothermic
   • always endothermic
   • sometimes exothermic and sometimes endothermic
5. When we mix salt and water, the change in entropy will be
   • positive
   • negative
   • we don't know
6. Gibbs free energy will tell you
   • whether a reaction is exothermic or endothermic
   • whether a reaction increases in entropy or decreases in entropy
   • whether a reaction is spontaneous
   • none of these
7. Endothermic reactions are more likely to be spontaneous
   • at low temperatures
   • at high temperatures
   • endothermic reactions are never spontaneous
   • endothermic reactions are always spontaneous
8. An endothermic reaction that occurs in a beaker will
   • get cold
   • get hot
   • stay the same temperature
   • could get hot or cold
9. Reactions that are spontaneous and decrease in entropy MUST be
   • exothermic
   • endothermic
10. Heat is a form of
    • kinetic energy
    • potential energy

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