Chemistry Quiz - Grade 10

Why is ΔHfus less than ΔHvap for water?

• Because water molecules move faster when melting

• Because breaking hydrogen bonds requires more energy

• Because less energy is needed to disrupt ice's structure than to separate water molecules

• Because ice is colder than liquid water

What is the significance of the heating curve for water?

• It shows temperature changes only

• It shows enthalpy changes during phase change

• It shows pressure changes only

• It shows volume changes only

During a phase change, which of the following occurs?

• Chemical bonds within molecules are broken

• New chemical compounds are formed

• The arrangement of molecules changes

• The molecular composition changes

During the melting process, the added energy is used to:

• Increase particle speed

• Breaking down intermolecular forces

• Raise the temperature

• Break chemical bonds

The hexagonal arrangement of water molecules in ice is:

• Higher in energy than liquid

• Lower in energy than liquid

• Equal in energy to liquid

• Variable in energy

What happens to kinetic energy during a phase change?

• It increases steadily

• It decreases steadily

• It remains constant

• It fluctuates randomly

The heat absorbed by a vaporizing liquid is ................... the heat released by a condensing gas.

• less than

• more than

• the same as

• there is no relation

How does Evaporation occur?

• Only at the boiling point

• Only when all molecules have sufficient energy

• At the surface of liquids below the boiling point

• When chemical bonds break

What is the effect of stronger intermolecular forces on ΔHvap?

• It increases ΔHvap.

• It has no effect

• It decreases ΔHvap

• It makes ΔHvap constant

The process where some particles at the surface of a liquid do have enough energy to break free.

• Melting

• Evaporation

• Condensation

• Freezing