Phase Changes

Which of the following is an example of an endothermic process?

• Freezing of water

• Combustion of wood

• Melting of ice

• Condensation of steam

Kynnli noticed droplets forming on the outside of her cold glass of water. This phase change from water vapor to liquid water is known as...

• evaporation

• precipitation

• condensation

• sublimation

Kylee and Keith are observing a balloon filled with air. They notice that the air inside the balloon

• has a definite shape but no definite volume

• has a definite volume but no definite shape

• has fast-moving particles

What is it called when Kylee observes dry ice, a solid, turning directly into a gas?

• Sublimation

• Condensation

• Liquid

During a science experiment, Keith and Kylee heated a pot of water on a stove. What happens to the water molecules as they add heat?

• They speed up and spread out

• They slow down and compress

• They stop moving

• They move closer together and speed up

All changes in the state of matter of a substance requires

• vibration
• water
• permission
• energy

During a science experiment, Keith observed an ice cube turning into water. Which phase change involves a solid turning into a liquid?

• freezing

• sublimation

• melting

• condensation

Kylee and Keith were observing the frost forming on the window. Kylee asked, "What is the process called when the Gas changes to Solid on the window?"

• Sublimation

• Deposition

• Fusion

• condensation

Keith and Kylee are in a chemistry lab, and they are studying the reaction: H₂ + 2 C + N₂ + 270.3 kJ --> 2 HCN. They need to determine if this reaction is endothermic or exothermic. Can you help them?

• Endothermic 

• Exothermic

Kylee and Keith are observing dry ice at a science fair. They notice that the solid dry ice turns directly into gas without becoming liquid. What is this phase change called?

• sublimation

• deposition

• evaporation

• condensation