Exploring Thermodynamics Concepts

What is the First Law of Thermodynamics also known as?

• Law of Conservation of Energy

• Law of Entropy

• Law of Heat Transfer

• Law of Disorder

Answer explanation

The First Law of Thermodynamics is also known as the Law of Conservation of Energy, which states that energy cannot be created or destroyed, only transformed from one form to another.

Tags

NGSS.HS-PS3-3

Which of the following statements best describes the Second Law of Thermodynamics?

• Energy cannot be created or destroyed.

• Heat flows from a colder body to a hotter body.

• The entropy of an isolated system always increases over time.

• Energy is conserved in a closed system.

Answer explanation

The Second Law of Thermodynamics states that the entropy of an isolated system always increases over time, indicating a natural tendency towards disorder. This distinguishes it from the other statements, which relate to energy conservation.

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

Identify the thermodynamic process where the pressure remains constant.

• Isothermal

• Adiabatic

• Isobaric

• Isochoric

Answer explanation

The isobaric process is characterized by constant pressure. In this process, the volume and temperature may change, but the pressure remains unchanged, making it distinct from isothermal, adiabatic, and isochoric processes.

Which heat transfer mechanism involves the movement of fluid?

• Conduction

• Convection

• Radiation

• Insulation

Answer explanation

Convection is the heat transfer mechanism that involves the movement of fluid, such as liquids and gases. In contrast, conduction occurs through direct contact, and radiation involves energy transfer through electromagnetic waves.

Calculate the change in internal energy if 500 J of heat is added to a system and the system does 200 J of work.

• 300 J

• 700 J

• 500 J

• 200 J

Answer explanation

The change in internal energy (ΔU) is calculated using the formula ΔU = Q - W, where Q is the heat added (500 J) and W is the work done by the system (200 J). Thus, ΔU = 500 J - 200 J = 300 J.

Tags

NGSS.HS-PS3-1

Explain why entropy is considered a measure of disorder in a system.

• Entropy measures the energy available for work.

• Entropy quantifies the number of ways a system can be arranged.

• Entropy is the total energy of a system.

• Entropy is the temperature of a system.

Answer explanation

Entropy is a measure of disorder because it quantifies the number of ways a system can be arranged. A higher entropy indicates more possible arrangements, reflecting greater disorder in the system.

In an adiabatic process, what happens to the temperature of a gas when it is compressed?

• It remains constant.

• It decreases.

• It increases.

• It fluctuates.

Answer explanation

In an adiabatic process, when a gas is compressed, work is done on the gas, increasing its internal energy, which raises its temperature. Therefore, the correct answer is that the temperature increases.

Tags

NGSS.HS-PS3-4

Describe a scenario where a system is in thermodynamic equilibrium.

• A pot of water boiling on a stove.

• A sealed container with gas at uniform temperature and pressure.

• A refrigerator cooling down food.

• A car engine running.

Answer explanation

A sealed container with gas at uniform temperature and pressure is in thermodynamic equilibrium because all parts of the system have the same temperature and pressure, with no net flow of energy or matter. This contrasts with the other scenarios.

Tags

NGSS.HS-PS3-4

A refrigerator is an example of which type of thermodynamic process?

• Isothermal

• Adiabatic

• Isobaric

• Cyclic

Answer explanation

A refrigerator operates through a cyclic thermodynamic process, where it continuously absorbs heat from the interior and expels it to the exterior, repeating this cycle to maintain a low temperature inside.

Tags

NGSS.HS-PS3-4

Analyze the impact of increasing entropy on the efficiency of a heat engine.

• Increases efficiency

• Decreases efficiency

• No impact on efficiency

• Efficiency becomes infinite

Answer explanation

Increasing entropy in a heat engine indicates greater disorder and energy dispersion, which leads to more energy being wasted as heat. This results in a decrease in the engine's efficiency, making 'Decreases efficiency' the correct choice.