Ph8 Orientation - Changes of state

Fill in the blank: The melting point of ice is _____

• 0°C

• 100°C

• -10°C

• 50°C

This statements is about the melting point of ice. "The temperature of ice taken out of the freezer is 0°C".

• I think this is right

• I think this is wrong

This statements is about the melting point of ice. "When it melts the temperature of ice is higher than 0°C".

• I think this is right

• I think this is wrong

This statements is about the melting point of ice. "The temperature of water in the beaker is 0°C until after all the ice has melted."

• I think this is right

• I think this is wrong

Which statement do you think best describes what happens as a substance changes state?

• A. The type of molecule of the substance changes.

• B. The mass of the molecules of the substance changes.

• C. The shape of the molecules of the substance changes.

• D. The connection between the molecules of the substance changes.

Which statement best explains what happens when water boils?

• The molecules are destroyed.

• The mass of the molecules decreases.

• The molecules become separated from each other.

• The molecules break down into hydrogen and oxygen atoms.

Which graph shows how temperature changes as the water is heated?

• A. [Graph A]

• B. [Graph B]

Kieran uses a hot grill to make cheese on toast. Under the grill the cheese melts and becomes a liquid. Which statement best explains why the cheese becomes a liquid?

• Some of the cheese molecules get smaller.

• Some of the cheese molecules are destroyed.

• The cheese molecules change into water molecules.

• The cheese molecules are more loosely connected to each other.

Salol is a chemical that melts at 41.5^oC (this is its melting and freezing point)

Some salol was warmed to 60^oC in a boiling tube and allowed to cool.

As it cools its temperature is measured using a thermometer.

As it cools, when does salol reach its freezing point?

• As soon it starts to change into its solid state.

• When about half of it is in a solid state.

• Only when all of it is in a solid state.

• At 0 degrees

BONUS QUESTION - After it reaches its freezing point, when does the temperature of salol start to fall again?

• As soon it starts to change into its solid state.

• When about half of it is in a solid state.

• Only when all of it is in a solid state.