The particulate nature of matter

Which statement describes a molecule?

• It consists of one nucleus surrounded by electrons

• It consists of two or more atoms bonded together

• It has a negative charge because it has gained electrons

• It has a positive charge because it has lost electrons

Which diagram shows a gas made up of molecules?

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The diagram represents the arrangements of particles in different physical states. Which arrow represents evaporation?

• A

• B

• C

• D

A fixed mass of argon gas in a sealed container is heated. The pressure inside the container increases. Which statement explains why the pressure increases?

• There is an increase in the number of gaseous particles inside the container

• There is an increase in the number of collisions per second between the particles of gas and the walls of the container

• The particles of gas have less energy and collide with the wall of the container more frequently

• There is a decrease in the space that the particles have to move in.

The melting point and boiling point of oxygen and nitrogen are shown.

A sealed flask contains a mixture of oxygen and nitrogen.

Which diagram shows the arrangement of oxygen and nitrogen particles at –190 C?

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What happens to water molecules when water is heated to 100 °C in a beaker?

• They gain energy and escape from the beaker

• They gain energy and move more slowly

• They lose energy and escape from the beaker

• They lose energy and move more slowly

A gas is stored in a sealed container of constant volume. The temperature of the gas increases.

This causes the pressure of the gas to increase.

What happens to the gas molecules during this pressure increase?

• The average kinetic energy of the molecules increases

• The average separation of the molecules decreases

• The average separation of the molecules increases

• The volume of each molecule increases

Air in a sealed syringe is slowly compressed by moving the piston. The temperature of the air stays the same.

Which statement about the air is correct?

• The pressure of the air decreases because its molecules now travel more slowly

• The pressure of the air decreases because the area of the syringe walls is now smaller

• The pressure of the air increases because its molecules now hit the syringe walls more frequently

• The pressure of the air increases because its molecules now travel more quickly

In which change of state do the particles gain kinetic energy and remain packed?

• gas to liquid

• liquid to gas

• liquid to solid

• solid to liquid

A substance Y has a melting point of –7ºC and a boiling point of 63ºC. At which temperature is Y a liquid?

• A

• B

• C

• D