Kinetic Theory

What does the kinetic theory state?

• All atomic motion stops when a molecule freezes.

• Atoms begin to vibrate when a liquid begins to boil.

• Atoms and molecules are constantly in motion.

• Atoms move at a constant speed at all temperatures.

Which of the following describes the motion of water molecules in ice?

• They are vibrating slightly.

• They move the same as in a liquid.

• They move faster than in a liquid.

• They do not move at all.

What does temperature measure?

• Kinetic energy within molecules

• Pressure within molecules

• Degrees within molecules

• Potential energy within molecules

What intermolecular force attracts two nonpolar molecules to each other?

• Van der Waals forces

• Hydrogen bonds

• Dipole-dipole attractions

• Covalent bonds

What happens when the temperature of a solid reaches its melting point?

• The kinetic energy breaks the bonds between atoms.

• The kinetic energy exceeds the intermolecular forces.

• The kinetic energy reaches its maximum amount.

• The kinetic energy within the molecules decreases.

How do intermolecular forces affect the boiling point of a liquid?

• The stronger the forces, the less heat that will be required to boil the liquid.

• The weaker the forces, the more heat that must be added to boil the liquid.

• The strength of the forces does not change the heat required to boil the liquid.

• The stronger the forces, the more heat that must be added to boil the liquid.

What information does a phase diagram give?

• The effect of temperature on volume changes of substances

• The effect of temperature and pressure on the phase of a substance

• The effect of oxidation number on the melting point of a metal

• The effect of concentration on the freezing point of a solution

What do the lines on a phase diagram represent?

• The lines distinguish between different molecules being compared.

• The lines form boundaries between the molecular state and the ionic state.

• The lines show where a phase change happens to a substance.

• The lines separate temperature effects from pressure effects.

Using the phase diagram for H₂O, what phase is water in at 1 atm pressure and -5C?

• It is in the gas phase.

• It is in the solid phase.

• It is in the liquid phase.

• It is at its melting point.

Using the phase diagram for CO₂, what phase is carbon dioxide in at -70C and 1 atm pressure?

• It is in the gas phase.

• It is in the solid phase.

• It is in the liquid phase.

• It is at its melting point.