Enthalpy and Entropy

The heat of reaction (△H) is equal to the

• entropy of the reactants minus the entropy of the products

• entropy of the products minus the entropy of the reactants

• heat content of the reactants minus the heat content of the products

• heat content of the products minus the heat content of the reactants

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Which of the following processes has a negative △S

• evaporating 1 mol of a liquid

• freezing 1 mol of a liquid

• raising the temperature of 1 L of water from 295 K to 350 K

• None of the other answer are correct.

Tags

NGSS.HS-PS3-4

Given the change of phase: CO₂(g) changes to CO₂(s), the entropy of the system

• remains the same

• You cannot determine the answer with the given information.

• increases

• decreases

Delta H is negative indicates

• reaction is exothermic

• reaction is endothermic

• reaction is spontaneous

• reaction is not spontaneous

Tags

NGSS.HS-PS1-4

A phase change from solid --> liquid

• shows a decrease in entropy

• shows an increase in entropy

• is exothermic

• is endothermic

A phase change from gas --> liquid

• shows a decrease in entropy

• shows an increase in entropy

• is exothermic

• is endothermic

Which of these would ALWAYS indicate a process is spontaneous?

According to Hess' law, if you reverse a reaction

• the sign of delta H must flip

• you do not change the delta H sign

• you must multiply the delta H value by 2

• you must divide the value of delta H by 2

Delta S is negative indicates

• enthalpy increases

• enthalpy decreases

• entropy decreases

• entropy increases

Which of the following statements about enthalpy (ΔH) is true?

• ΔH is always positive for exothermic reactions

• ΔH is always negative for endothermic reactions

• ΔH is positive for endothermic reactions

• ΔH is negative for reactions at equilibrium