Background: Figure above summarizes the basic transitions that a substance may undergo as a result of changes in temperature or pressure. For any phase change, energy will be either released (for exothermic processes) or absorbed from the surroundings (for endothermic processes). Processes in which intermolecular interactions are weakened or broken (melting, vaporization, and sublimation) require an input of energy; they are endothermic. Processes in which attractive interactions are formed (freezing, condensation, and deposition) release energy, so they are exothermic.

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: Which unit of water will be undergoing an endothermic process?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: Which unit of water will be undergoing an exothermic process?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: Will Unit A be undergoing an endothermic or exothermic process?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: Will Unit B be undergoing an endothermic or exothermic process?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: In which unit will the intermolecular interactions be weakened or broken?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: In which unit will attractive interactions be formed?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: For which unit will the change in state cause energy to be released?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: For which unit will the change in state cause energy to be absorbed from the surroundings?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: Will the change in state for unit A cause energy to be released or absorbed?

Situation: Bethany is curious about the changes that occur when water changes states due to temperature changes. To study this, she observes two different units of water. Unit A is frozen and will be heated until melted. Unit B is liquid and will be cooled until frozen.

Question: Will the change in state for unit B cause energy to be released or absorbed?