What principle do air conditioners use to cool down a room?

• As a liquid evaporates into a gas, it absorbs heat.

• As a gas condenses into a liquid, it releases heat.

• As a liquid freezes into a solid, it absorbs heat.

• As a solid melts into a liquid, it releases heat.

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What happens to the molecules in a liquid as they absorb enough heat energy?

• They overcome intermolecular attractions and take gaseous form.

• They remain in a liquid state but move faster.

• They form stronger chemical bonds.

• They freeze into a solid state.

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What is the basic job of an air conditioner?

• To decrease the humidity inside a room.

• To purify the air inside a room.

• To increase the temperature inside a room.

• To move heat from one place to another using a refrigerant.

What does the compressor in an air conditioner do?

• It increases the pressure on the gaseous refrigerant to condense it back into a liquid.

• It reduces the pressure on the gaseous refrigerant.

• It heats up the refrigerant.

• It cools down the refrigerant.

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Why do air conditioners contribute to high power bills in July?

• Because they are typically larger and consume more space.

• Because they require water to operate.

• Because the compressor needs energy to compress the refrigerant.

• Because they are used less frequently.

What characteristic does a refrigerant need to have?

• To be flammable and toxic.

• To be solid at room temperature.

• The ability to absorb a lot of heat as it boils.

• A high boiling point.

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What was the problem with chlorofluorocarbons (CFCs) as refrigerants?

• They were too expensive.

• They were too flammable.

• They were not effective as refrigerants.

• They caused damage to the ozone layer.

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What is a disadvantage of hydrofluorocarbons (HFCs)?

• They are not widely available.

• They have a high boiling point.

• They are greenhouse gases.

• They damage the ozone layer.

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Which of the following is considered a potential refrigerant due to its less potent greenhouse effect compared to HFCs?

• CO2

• Freon

• Oxygen

• Nitrogen

Why is it unlikely that we will give up on using air conditioning?

• Because it is inexpensive to operate.

• Because air conditioners also purify the air.

• Because there are no alternatives to cool down spaces.

• Due to the comfort it provides during scorching summers.

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