chemistry HW Sec 1
Multiple Choice
Identify the choice that best completes the statement or answers the question.
Choose the best answer from the options that follow each question.
_d_
1. The topics covered by the study of thermodynamics include
a. energy changes during heating.
b. energy changes during chemical reactions.
c. color changes during chemical reactions.
d. Both (a) and (b)
__a__ 2. Energy is measured in units of
a. joules.
b. kelvins.
c. pounds.
d. grams.
__b__ 3. What symbol is used to represent enthalpy?
a. K
b. H
c. E
d. None of the above
__a__ 4. The specific heat of a substance is the amount of energy needed to raise the temperature of
a. 1 g by 1 K.
b. 1 mol by 1 K.
c. 1 g by 1°F.
d. 1 mol by 1°F.
__c__ 5. Which of the following is not needed to calculate the energy required to increase the temperature of
a substance?
a. the mass of the substance
b. the specific heat of the substance
c. the molar mass of the substance
d. the temperature change
__c__ 6. For a given substance, the term
a. the total energy.
b. the total enthalpy.
H refers to
c. the change in enthalpy.
d. the change in temperature.
__c__ 7. Given the total enthalpy of the products in a reaction and the total enthalpy of the reactants, what is
H for the reaction?
a.
enthalpy of product × enthalpy of reactants
b.
c. enthalpy of product - enthalpy of reactants
d. enthalpy of reactants - enthalpy of products
__b__ 8. If the H of a system is measured as -177 kJ, the change is
a. endothermic.
b. exothermic.
c. either endothermic or exothermic.
d. reversible.
__c__ 9. The energy absorbed or released during a reaction in which a substance is produced is called the
a. calorie change.
b. standard condition.
c. enthalpy of formation.
d. heat.
__b__10. According to Hess’s law, the overall enthalpy change in a reaction
a. equals the difference of enthalpy changes for the individual steps in the reaction.
b. equals the sum of enthalpy changes for the individual steps in the reaction.
c. equals the enthalpy change of the first step in the reaction.
d. cannot be determined from the enthalpy changes for the individual steps in the
reaction.