Thermodynamics

The entropy of a system decreases when:

• A liquid changes into a solid.

• A liquid changes into a gas.

• A molecule is broken into two or more smaller molecules.

• A reaction occurs that results in an increase in the number of moles of gas.

Which of the following is another term for the heat of reaction?

• Gibbs Free Energy.

• Specific Heat Capacity.

• Entropy change.

• Enthalpy change.

Tags

NGSS.HS-PS1-4

The heat of reaction is -85.0 kJ and the entropy change for the reaction is +9.50 J/K. At 298K, what is the value of Delta G, and will the process be spontaneous or non-spontaneous?

• -2,746 kJ; Non-spontaneous

• -82.2 kJ; Non-spontaneous

• -87.8 kJ; Spontaneous

• -82.2 kJ; Spontaneous

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NGSS.HS-PS1-4

NGSS.HS-PS3-1

Which of the following conditions is MOST likely to produce a spontaneous reaction at all temperatures?

• Negative entropy and positive enthalpy.

• Positive entropy.

• Negative enthalpy and positive entropy.

• Positive enthalpy.

For a reaction to be spontaneous, the sign of delta G must be:

• Positive or negative.

• Negative.

• Neither positive nor negative.

• Positive.

What does it mean when the enthalpy change for a reaction is negative?

• that the reaction is exothermic

• that the reaction needed energy to get started

• that the reaction was spontaneous

• that the reaction won't take place

• that the reaction is endothermic

Tags

NGSS.HS-PS1-4

When a bond forms, energy is given off to the surroundings. This is an example of

• Newton's third law.

• an exothermic reaction

• the law of conservation of matter.

• an endothermic reaction

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NGSS.HS-PS1-4

An example of an exothermic reaction is:

• when two chemicals are added together

• the breaking of bonds

• an instant cold pack

• evaporation of water

• the lighting of a match

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NGSS.HS-PS1-4

An endothermic reaction is:

• when the system gains heat as the surroundings cool down.

• when energy is either created or destroyed

• when one or more substances are changed into one or more different substances.

• when the reaction involves subatomic particles

• when the system loses heat as the surroundings heat up.

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Enthalpy change is

• the amount of energy as heat that is lost or gained by a system

• a chemical reaction

• when energy is neither created nor destroyed

• when one or more substances are changed into one or more different substances.

• the total amount of energy in a system

Tags

NGSS.HS-PS1-4