Heat and temperature Knowledge-Based Practice

Questions

1. 1.

   Two distinct substances of identical mass and initial temperature each absorb the same quantity of heat without undergoing a phase change. Which statement correctly explains why their final temperatures differ?

   • A) They possess different specific heat capacities, meaning each substance requires a different quantity of heat per unit mass to alter its temperature by one degree.
   • B) Heat is an intensive property that alters the kinetic energy of different materials at identical rates regardless of their chemical identity.
   • C) The substance with the higher heat capacity absorbs heat faster, causing it to achieve a greater temperature rise under identical thermal input.
   • D) Temperature is a measure of total thermal energy, which varies independently of heat capacity in pure substances.
2. 2.

   During a phase change of a pure substance, such as melting or boiling, heat is continuously added while the temperature remains constant. Which statement correctly explains what happens to the absorbed heat during this process?

   • A) It increases the average translational kinetic energy of the particles while keeping their potential energy constant.
   • B) It increases the potential energy of the particles by overcoming intermolecular attractions rather than increasing their average kinetic energy.
   • C) It is completely dissipated to the surroundings as radiant energy, preventing any change in internal energy.
   • D) It decreases the total internal energy of the system by lowering the vibrational frequencies of the chemical bonds.
3. 3.

   Which statement correctly describes the condition that determines the direction of spontaneous heat transfer between two objects in thermal contact and the criterion for their thermal equilibrium?

   • A) Heat transfers spontaneously from the object at higher temperature to the object at lower temperature until both objects reach the same temperature.
   • B) Heat transfers spontaneously from the object with greater total thermal energy to the object with lower thermal energy until their thermal energies become equal.
   • C) Heat transfers spontaneously from the object with higher specific heat capacity to the object with lower specific heat capacity until both specific heat capacities equilibrate.
   • D) Heat transfers spontaneously from the object of greater mass to the object of lesser mass until the heat content of both objects is identical.
4. 4.

   A 50 g sample of pure iron and a 500 g sample of pure iron are both held at a uniform temperature of 25 °C. Which statement correctly compares the temperature and the thermal energy of these two samples?

   • A) Both samples possess identical thermal energies because they are at the same temperature, but the 500 g sample has a lower average particle kinetic energy.
   • B) The 50 g sample possesses a higher thermal energy because thermal energy is inversely proportional to mass at a constant temperature.
   • C) Both samples possess identical thermal energies and identical temperatures because thermal energy is an intensive property that does not depend on mass.
   • D) Both samples have the same temperature because their particles have the same average kinetic energy, but the 500 g sample possesses a greater thermal energy due to its larger mass.
5. 5.

   Which of the following statements correctly describes the fundamental thermodynamic relationship between heat and temperature?

   • A) Temperature is an extensive property that measures the total quantity of thermal energy transferred during a process.
   • B) A closed thermodynamic system contains a definite, measurable quantity of heat proportional to its absolute temperature.
   • C) Heat is the transfer of thermal energy driven by a temperature difference, whereas temperature reflects the average kinetic energy of particles.
   • D) Heat flows spontaneously between two bodies in thermal contact until both objects possess identical amounts of total thermal energy.

Answers and step-by-step solutions appear after you finish the test.