Concept Check

Should the following reaction be endothermic or exothermic? O₂N–NO₂ → O₂N + NO₂

• Endothermic

• Exothermic

What type of reaction is described if it involves only the breaking of a chemical bond?

• Exothermic

• Endothermic

• Neutral

• Spontaneous

Fill in the blank: ________ is conserved in a chemical reaction.

• Energy

• Mass

• Volume

• Temperature

What is the area of science concerned with energy’s roles?

• Biology

• Thermodynamics

• Physics

• Chemistry

Fill in the blank: The first law of thermodynamics states that energy does not ________ or ________.

• appear, disappear

• increase, decrease

• multiply, divide

• expand, contract

Fill in the blank: One of the main driving forces of chemical and physical changes is the tendency of ______ to disperse.

• energy

• mass

• volume

• pressure

Which of the following best describes reactions that concentrate energy?

• They tend to occur frequently

• They do not tend to occur

• They always release energy

• They are described by the first law of thermodynamics

Fill in the blank: The tendency of energy to disperse is described by the ______ law of thermodynamics.

What is entropy?

• Measure of the spreading of energy

• Measure of the concentration of energy

• Measure of the speed of a reaction

• Measure of temperature

An increase in entropy corresponds to a ________ of energy.

• spreading

• concentration

• loss

• creation