Unit Test Answers

Sixty-three joules of heat are added to a closed system. The initial internal energy of the system is 58 J, and the final internal energy is 93 J.

The diagram shows an engine piston before and after heat is added, which illustrates the laws of thermodynamics.

Substance X transfers thermal energy to substance Y through conduction. What is an accurate conclusion about the condition of both substances before conduction occurred?

Jin knows that the initial internal energy of a closed system is 78 J and the final internal energy is 180 J. He also knows that 64 J of energy are used to do work. To find the heat added to the system, Jin completes the steps below.1. Add the initial internal energy plus the final internal energy to find the change in internal energy. 2. Add the change in internal energy to the energy used to do work.3. Write the answer in joules.

Which is the best example of decreasing entropy?

In the heat equation, what does Q represent?

A heat engine has a temperature of 1800 K. Some of the heat from the engine flows to the surroundings, which are at a temperature of 160 K.

Chen explained that heat engines illustrate only the second law of thermodynamics because they involve the flow of thermal energy from hot to cool areas. His friend Mia disagreed and explained that these engines illustrate only the first law of thermodynamics because they are sometimes 100 percent efficient if they conserve enough energy.

According to the first law of thermodynamics, what could happen when heat is added to a system?

The chart shows the temperatures of four different substances.

A substance has a specific heat of 0.870 J/g°C. It requires 2,000.0 joules to increase the temperature of 10.0 grams of the substance from its original temperature to its final temperature.

Suppose the exhaust system on a heat engine is not functioning properly. Which statement best explains how this will affect the engine?

Which best describes the relationship between internal energy and thermal energy?

Allen made a diagram to compare radiation and conduction.

Temperatures of four liquid substances are shown in the chart.