Understanding Temperature and Phase Changes

What is the primary factor that determines the speed of particle movement in a substance?

• The shape of the container

• The amount of heat energy

• The color of the substance

• The size of the particles

At what temperature does pure water melt?

• 50° C

• 32° C

• 0° C

• 100° C

Which of the following substances requires a high temperature to melt?

• Gold

• Salt

• Wax

• Ice

What happens to particles in a liquid when it reaches its boiling point?

• They become tightly packed

• They stop moving

• They gain energy and form bubbles

• They slow down and form a solid

At what temperature does water boil under standard atmospheric pressure?

• 100° C

• 0° C

• 50° C

• 150° C

What is the freezing point of pure water?

• 100° C

• 32° C

• 50° C

• 0° C

Why can the melting and freezing points of water be the same?

• Because of impurities

• Because water is a unique substance

• Because they occur at equilibrium

• Because of atmospheric pressure

What effect does adding salt have on the melting point of ice?

• It has no effect

• It raises the melting point

• It makes the ice evaporate

• It lowers the melting point

Why are roads salted in winter?

• To lower the melting point of ice

• To make roads slippery

• To prevent snow

• To raise the temperature

What is the significance of the temperature 0° C for water?

• It is the freezing and melting point

• It is the point of condensation

• It is the point of evaporation

• It is the boiling point