Physics Thermodynamics Test 12. When a solid sample was heated, its temperature increased but it did not melt. How can the changes in the average molecular kinetic and potential energies of the atoms in the sample best be described? A Potential energy decreased and kinetic energy remained the same C B Potential energy increased and kinetic energy remained the same D Kinetic energy decreased and potential energy remained the same Kinetic energy increased and potential energy remained the same 13. A spoon, a fork, and a knife are stacked on top of each other overnight. The temperature of both the fork and spoon is 21C the next morning. According to the laws of thermodynamics, what can be predicted about the temperature of the knife? A The temperature of the knife is also 21C because equilibrium has been reached between all three objects. B The temperature of the knife could only be determined through measurement. The temperature of the spoon and fork are both conducted to the knife giving it a resulting temperature of 42C. D The temperature of the knife would be 140C because the knife represents roughly one third of the overall mass. 14. Measurements inside a sealed container show that the pressure exerted by a gas decreases as the thermal energy of the gas decreases. Which of the following best explains this pressure change? Gas molecules will stick to the walls of the container because of a decrease in their viscosity. B Gas molecules will radiate energy in the form of nuclear particles because of a decrease in molecular stability. C Gas molecules will strike the container walls less frequently and with less energy because of a decrease in their velocity. D Gas molecules will form chemical bonds creating heavier complex molecules. A B 100 .C 40 C 15. Two cubes of tin were heated to different temperatures and then placed in direct contact with each other. Each cube of tin each has a mass of 1.0 kg. Assuming the cubes are in an isolated system, what is the equilibrium temperature of the blocks? 40 C 70 C 100 C 140 C