Thermodynamics (Present in order)

What is thermodynamics?

• movement of heat

• it's magic

• measurement of heat

• none of them

Answer explanation

Thermodynamics is the study of heat and its movement. The correct choice, 'movement of heat', accurately describes this field, as it focuses on how heat energy is transferred and transformed in various systems.

Tags

NGSS.HS-PS3-4

Energy is created by....

• running

• boiling ice

• touching slime

• none of them

Answer explanation

Energy is not created by running, boiling ice, or touching slime. These actions do not generate energy; rather, energy is transformed or transferred. Therefore, the correct answer is 'none of them'.

Which way does heat flow?

• hot to cold

• cold to hot

• it doesn't 

Answer explanation

Heat flows from hot to cold areas due to the second law of thermodynamics, which states that energy naturally disperses from regions of higher temperature to regions of lower temperature until thermal equilibrium is reached.

Tags

NGSS.HS-PS3-4

What is absolute zero?

• 0 K

• 273 K

• 0^oC

• -273K

Answer explanation

Absolute zero is the theoretical lowest temperature possible, defined as 0 Kelvin (0 K). At this temperature, all molecular motion stops, making 0 K the correct answer.

What is a spontaneous process ?

• slow process

• fast process

• process that needs an external intervention to occur

• process that does not need external intervention to occur / keep happening

Answer explanation

A spontaneous process is one that occurs naturally without the need for external intervention. This means it can happen on its own, making the correct choice "process that does not need external intervention to occur / keep happening."

Which has higher entropy?

A. An enclosed space is filled with ash and smoke particles.

B. A pile of logs sits on the floor of an enclosed space.

• A

• B

Answer explanation

Option A has higher entropy because ash and smoke particles are dispersed and chaotic, representing a greater degree of disorder compared to the organized structure of a pile of logs in option B.

Which of the following is the best example of The Second Law of Thermodynamics?

• A bike parked at the top of a hill has stored potential energy

• A bike rolling down a hill has kinetic energy

• Water flowing over a dam is used to generate electricity

• Some of the potential energy stored in gasoline is lost as heat when burned in a car's engine

Answer explanation

The Second Law of Thermodynamics states that energy transformations are not 100% efficient. In a car engine, some potential energy from gasoline is converted to heat, illustrating energy loss, making this the best example.

Tags

NGSS.HS-PS3-4

Which statement is true about the ENTROPY?

• Entropy refers to DISORDER, the unusable energy that escapes a system.

• Entropy refers to the balance of temperature among two or more systems.

• Entropy refers to the average kinetic energy of the molecules.

• Entropy refers to the inability to destroy or create energy. 

Answer explanation

The correct statement about entropy is that it refers to DISORDER, representing the unusable energy that escapes a system. This aligns with the second law of thermodynamics, which states that entropy tends to increase in isolated systems.

Tags

NGSS.HS-PS3-4

According to the 2nd law of thermodynamics, a heat engine cannot be 100% efficient. Why?

• the adiabatic step is not reversible

• the isothermal process is not reversible

• some heat is transferred to the environment

• not enough power is generated

Answer explanation

According to the 2nd law of thermodynamics, some heat is always lost to the environment during energy conversion, preventing a heat engine from achieving 100% efficiency.

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

What does this diagram show?

• a non-reversible isothermal process

• a pressure-volume diagram for the Carnot Cycle

• a pressure-volume diagram for any Ideal Gas

• a non-reversible adiabatic process

Answer explanation

The diagram represents a pressure-volume diagram for the Carnot Cycle, which illustrates the idealized thermodynamic cycle involving isothermal and adiabatic processes, distinguishing it from other processes.

Tags

NGSS.HS-PS3-1