EOM: Temperature and Kinetic Energy

Oliver and Nora are observing a pot of water being heated on a stove. Which of the following statements best describes the relationship between the temperature of the water and the kinetic energy of its particles?

• As kinetic energy decreases, temperature is not affected.

• As kinetic energy increases, temperature decreases.

• As kinetic energy decreases, temperature increases.

• As kinetic energy increases, temperature increases.

Answer explanation

The correct statement is that as kinetic energy increases, temperature increases. This is because temperature is a measure of the average kinetic energy of the particles in a substance.

Jackson was asked to draw a concept map of changes in matter at the molecular level. An incomplete sample is provided here. Which of the following labels would be most appropriate for completing the diagram?

• Arrow A = Particles become more tightly packed.

• Arrow B = The temperature of the substance does not change.

• Arrow C = Kinetic energy of particles increases.

• Arrow D = Particles become more widely spaced.

Answer explanation

Arrow A is correct because when matter changes state, such as from gas to liquid, particles become more tightly packed. This reflects a decrease in kinetic energy and a transition to a more ordered state.

Arjun and Mason each have a sealed balloon filled with nitrogen gas. Both balloons contain the same number of nitrogen gas molecules. The gas molecules in Mason's balloon have twice the average speed of the molecules in Arjun's balloon. Which of the following statements best describes the nitrogen gas in Mason's balloon?

• The nitrogen gas in Mason's balloon has a greater mass than the nitrogen gas in Arjun's balloon.

• The nitrogen gas in Mason's balloon has a greater temperature than the nitrogen gas in Arjun's balloon.

• The nitrogen gas in Mason's balloon has a greater density than the nitrogen gas in Arjun's balloon.

• The nitrogen gas in Arjun's balloon has a greater temperature than the nitrogen gas in Mason's balloon.

Answer explanation

The average speed of gas molecules is directly related to temperature. Since Mason's gas molecules have twice the average speed, the nitrogen gas in Mason's balloon has a greater temperature than in Arjun's balloon.

Arjun conducted an experiment. He placed granules in a beaker of water. He measured the temperature before and after. The change in temperature gives Arjun information about the mixture best described by which of the following?

• The decrease in the kinetic energy of the particles

• The quantity of heat released by the mixture

• The current arrangement of atoms in the mixture

• The ability of the mixture to conduct an electric current

Answer explanation

The change in temperature indicates the quantity of heat released by the mixture, as temperature changes reflect energy transfer. This choice best describes the thermal effects observed in Arjun's experiment.

Ethan is observing a solid plastic cube in his science class. The graph below represents changes in particle motion in the cube over time. The changes in the particles of the plastic cube must be accompanied by which of the following?

• An increase in mass

• A decrease in mass

• An increase in temperature

• A decrease in temperature

Answer explanation

As the particle motion in the plastic cube changes, it indicates a decrease in temperature. Lower temperatures reduce kinetic energy, leading to slower particle motion, which aligns with the observed changes.

Henry is observing a pot of water on the stove. As the water heats up, steam begins to rise from the surface. Which of the following statements describes the particles in the steam? Select two correct answers.

• The particles have more kinetic energy than the particles in the cooler water below.

• The particles have a lower temperature than the particles in the cooler water below.

• The particles have less kinetic energy than the particles in the cooler water below.

• The particles have no kinetic energy.

• The particles have a higher temperature than the particles in the cooler water below.

Answer explanation

The steam particles have more kinetic energy and a higher temperature than the cooler water below, as they are in a gaseous state, indicating increased energy compared to the liquid state of water.

Michael and Anika are observing different phases of matter in their science class. Complete the chart below. Match the correct components to the appropriate location on the chart. Kinetic Energy of the System: In this phase, the system has the greatest amount of kinetic energy.

• Phase of Matter: Gas Model and Description of Particles in the System: Particles are widely separated and move very quickly.

• Phase of Matter: Solid Model and Description of Particles in the System: Particles are tightly packed and vibrate in place.

• Phase of Matter: Liquid Model and Description of Particles in the System: Particles are close together but can move past each other.

• Phase of Matter: Plasma Model and Description of Particles in the System: Particles are ionized and move extremely fast.

Answer explanation

In the gas phase, particles are widely separated and move very quickly, indicating the highest kinetic energy compared to solids and liquids, where particles are more constrained.

Rohan is conducting an experiment to understand different phases of matter. He has a chart that lists characteristics of a simple system. Help Rohan complete the chart by matching the correct components to the appropriate location on the chart.

• Phase of Matter: Liquid Model and Description of Particles in the System: Particles move past each other but remain in contact.

• Phase of Matter: Solid Model and Description of Particles in the System: Particles move freely and are far apart.

• Phase of Matter: Gas Model and Description of Particles in the System: Particles are tightly packed and vibrate in place.

• Phase of Matter: Plasma Model and Description of Particles in the System: Particles are ionized and move independently.

Answer explanation

In the liquid phase, particles move past each other while remaining in contact, which distinguishes it from solids, gases, and plasmas. This matches the description provided for liquids.

Zoe is conducting an experiment in her science class. She needs to complete the chart below by matching the correct components to the appropriate location on the chart. Kinetic Energy of the System: In this phase, the system has the least amount of kinetic energy.

• Phase of Matter: Solid Model and Description of Particles in the System: Particles are closely spaced and vibrate.

• Phase of Matter: Liquid Model and Description of Particles in the System: Particles are loosely packed and move past each other.

• Phase of Matter: Gas Model and Description of Particles in the System: Particles are far apart and move freely.

• Phase of Matter: Plasma Model and Description of Particles in the System: Particles are ionized and move very rapidly.

Answer explanation

In the solid phase, particles are closely spaced and vibrate, resulting in the least amount of kinetic energy compared to liquids, gases, and plasmas, where particles have more freedom of movement.

Abigail and Daniel are conducting an experiment with two beakers of liquid. Which of the following describes the molecules of the liquid in the beaker on the left?

• The molecules in the left beaker have more kinetic energy than the molecules in the right beaker.

• The molecules in the left beaker have less kinetic energy than the molecules in the right beaker.

• The molecules in the left beaker have no kinetic energy.

• The molecules in the left beaker have the same amount of kinetic energy as the molecules in the right beaker.

Answer explanation

The correct choice indicates that the molecules in the left beaker have less kinetic energy than those in the right beaker, suggesting a temperature difference or state of matter affecting their energy levels.