PhysSci_1st6wksmidtermquiz

Which of the following will absorb heat energy?

• two sticks being rubbed together

• a piece of wood burning

• steel wool rusting

• ice cubes melting

An ice cube is initially at a temperature of -20°C. Heat is added, causing the ice to change phases, first melting to water then changing to steam. The diagram shows the changes in temperature as heat is added to the system. Which statement below is true?

• As heat is added to Stage 2, the temperature of the ice cube increases to 0°C.

• As heat is added to Stage 3, the temperature of the water increases from 0 to 100°C.

• As heat is added to Stage 4, the temperature is constant and the ice cube melts to form water.

• As heat is added to Stage 5, the water that was in the ice cube is transformed into water vapor.

A sample of sulfur forms crystals when it

• melts.

• freezes.

• evaporates.

• condenses.

Anita heats a beaker containing water. As the temperature of the water increases, which change to the water molecules occurs?

• The molecules move at a faster rate.

• The molecules become more massive.

• The molecules expand and become wider.

• The molecules separate into atoms of hydrogen and oxygen.

Which has the lowest kinetic energy?

• I

• II

• III

Which has the intermediate kinetic energy?

• I

• II

• III

Which has the highest kinetic energy?

• I

• II

• III

A substance is heated at a constant rate, and the temperature is recorded over time. A graph of the data is shown. Which statement BEST describes why the temperature remains constant during certain time intervals?

• Heat is not distributed evenly throughout the substance.

• Energy is required to change the phase of the substance.

• Electrons in the atoms are set free at certain temperatures.

• Energy levels in the atoms absorb energy in specific amounts.

What happens to the molecules of a substance when it is heated?

• The molecules move slower and get closer together.

• The molecules move slower and get farther apart.

• The molecules move faster and get closer together.

• The molecules move faster and get farther apart.

For any substance, which phase change requires a gain of the largest amount of energy?

• solid to liquid

• liquid to solid

• solid to gas

• gas to solid