Unit 4 Part 1 LM Questions

What kind of system is an exploded hydrogen balloon?

•   Open system

•   Closed system

•   Isolated system

•   No way to tell.

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LM 49

You purchase a chilled bottle of water at the convenience store.  Over time it absorbs energy and warms up.  What kind of system is it and where did the heat come from to warm it up?

•   Open system, system

•   Closed system, universe

•   Open system, surroundings

•   Closed system, surroundings

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LM 49

If I were to spray perfume at the corner of a classroom, the perfume would gradually spread out evenly until it fills the entire room. Which law of thermodynamics does this best exemplify?

•   The First Law of Thermodynamics

•   The Second Law of Thermodynamics

•   The Third Law of Thermodynamics

•   It actually violates all of these laws.

Answer explanation

This best exemplifies the Second Law of Thermodynamics, which states that energy tends to spread out and become more evenly distributed over time. In this case, the energy of the perfume molecules is spreading out and becoming more evenly distributed throughout the classroom.

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LM 49

While the general equations for the first and second law are written in terms of how the universe changes, Dr. Laude's preference is that we quickly rewrite them to reflect changes in what?

•   the system

•   the surroudings

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LM 49

Which of the state functions are related to the first law of thermodynamics?

•   E and H

•   E and G

•   S and E

•   All of them

Answer explanation

The first law of thermodynamics states that energy can neither be created nor destroyed, but can be converted from one form to another. As such, the state functions related to the first law of thermodynamics are those that measure the energy of a system, such as internal energy, enthalpy, and entropy. These state functions are used to calculate the amount of energy that is transferred in or out of a system during a process.

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LM 49

Which of the state functions are related to the second law of thermodynamics?

•   S and G

•   S and H

•   All of them

•   G and E

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LM 49

Which of the following is NOT a state function?

•   Number of moles

•   Pressure

•   Enthalpy

•   Heat

Answer explanation

Heat is not a state function. Heat is a form of energy that is transferred between two objects due to a temperature difference. It is not a property of a system that is independent of the path taken to reach the state.

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LM 49

Which of the following is associated specifically with the productive use of internal energy?

•   w

•   q

•   E

•   S

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LM 49

You put your hands out to warm them next to a fire.  What is the sign for heat for the system?

• negative

•   positive

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LM 50

You observe salt dissolve in water.  What is the sign of ΔG? 

• negative

•   positive

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LM 50