Understanding the First Law of Thermodynamics

What is the change in internal energy if 60 joules of work is done on a gas and it loses 150 joules of heat?

• -210 joules

• 90 joules

• -90 joules

• 210 joules

What does the First Law of Thermodynamics help us determine?

• The change in internal energy

• The volume of a gas

• The speed of a gas

• The pressure of a gas

In the context of the First Law, what does a negative sign for heat indicate?

• Heat is added to the system

• Heat is lost from the system

• Heat is constant

• No heat transfer occurs

If the internal energy of a gas decreases, what happens to its temperature?

• It increases

• It remains constant

• It decreases

• It becomes zero

What is the relationship between internal energy and temperature?

• They are unrelated

• They are directly proportional

• They are inversely proportional

• They are equal

What must be known to determine the exact change in temperature from a change in internal energy?

• The volume of the gas

• The type of gas

• The specific heat capacity of the gas

• The pressure of the gas

A gas starts with 200 joules of internal energy. If 180 joules of heat is added and the gas does 70 joules of work, what is the final internal energy?

• 200 joules

• 310 joules

• 250 joules

• 110 joules

If a gas does work, how is this represented in the First Law equation?

• As a positive value

• As a constant

• As a negative value

• As zero

When 40 joules of work is done on a gas and its internal energy decreases by 150 joules, what is the heat added to the gas?

• -110 joules

• -190 joules

• 110 joules

• 190 joules

Why is it important to be careful with positive and negative signs in thermodynamics?

• They affect the color of the gas

• They determine the direction of energy transfer

• They alter the chemical composition

• They change the state of matter