Changes in Energy at the Molecular Level A/B

Which of the following changes made to a sample of liquid would result in an increase in the distance between the individual molecules of the substance?

• Transferring the substance to a smaller container

• Adding heat energy to the substance

A student drew a representation of the atoms of a solid. The illustration shows closely packed atoms vibrating, but remaining in the same relative positions. Which of the following changes must the student make to the illustration to accurately represent the same substance in the liquid phase?

• The illustration should show increased movement of the atoms

• Each individual atom should be much larger

As thermal energy is added to a substance, which of the following changes can be predicted?

• Spacing between particles will decrease

• Vibration of individual particles will increase

Which of the following statements best describes the relationship between temperature and kinetic energy of particles in a substance?

• As kinetic energy decreases, temperature is not affected

• As kinetic energy increases, temperature increases

Students were 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?

• A = particles become more tightly packed

• B = the pressure of the substance decreases

• C = kinetic energy of particles increases

• D = particles become more widely spaced

Which list shows the states of matter in order of greatest amount of energy to least?

• solid, liquid, gas

• gas, liquid, solid

This image shows particles in a solid state because they are tightly packed together and vibrating.

• true

• false

These molecules are loosely packed and able to flow relative to each other. Which state are they showing?

• gas

• liquid

• gas

This picture shows the particle movement in a gas. What statements are true about gas particles?

• particles are tightly packed together

• particles move around freely

• particles move quickly and may collide with objects

What is the basic unit of an element?

• atom

• solid