General Chemistry Principles, Patterns, and Applications, 2011

. Water evaporates from your skin, causing you to shiver.
c. A container of ammonium nitrate detonates.
4. Is Earth’s environment an isolated system, an open system, or a closed system? Explain your answer.
5. Why is it impossible to measure the absolute magnitude of the enthalpy of an object or a compound?
6. Determine whether energy is consumed or released in each scenario. Explain your reasoning.
a. A leaf falls from a tree.
b. A motorboat maneuvers against a current.
c. A child jumps rope.
d. Dynamite detonates.
e. A jogger sprints down a hill.
7. The chapter states that enthalpy is an extensive property. Why? Describe a situation that illustrates this fact.
8. The enthalpy of a system is affected by the physical states of the reactants and the products. Explain why.
9. Is the distance a person travels on a trip a state function? Why or why not?
10. Describe how Hess’s law can be used to calculate the enthalpy change of a reaction that cannot be observed
directly.
11. When you apply Hess’s law, what enthalpy values do you need to account for each change in physical state?
a. the melting of a solid
b. the conversion of a gas to a liquid
c. the solidification of a liquid
d. the dissolution of a solid into water
12. In their elemental form, A 2 and B 2 exist as diatomic molecules. Given the following reactions, each
13. For the formation of each compound, write a balanced chemical equation corresponding to the standard
enthalpy of formation of each compound.
a. HBr
b. CH 3 OH
c. NaHCO 3
14. Describe the distinction between ΔH soln and ΔH f .
15. Does adding water to concentrated acid result in an endothermic or an exothermic process?
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