When is the energy crossing the boundaries of a closed

Principles of General Chemistry 2
Chromium(III) oxide reacts with hydrogen sulfide (\(\mathrm{H}_{2} \mathrm{~S}\)) gas to form chromium(III) sulfide and water: \(\mathrm{Cr}_{2} \mathrm{O}_{3}(\mathrm{~s})+3 \mathrm{H}_{2} \mathrm{~S}(\mathrm{~g}) \rightarrow \mathrm{Cr}_{2} \mathrm{~S}_{3}(\mathrm{~s})+3 \mathrm{H}_{2} \mathrm{O}

Organic Chemistry 7
a. Which of the following has a nonpolar covalent bond? b. Which of the following has a bond closest to the ionic end of the bond spectrum? \(\mathrm{CH}_{3} \mathrm{NH}_{2}\) \(\mathrm{CH}_{3} \mathrm{CH}_{3}\) \(\mathrm{CH}_3\mathrm{F}\) \(\mathrm{CH}_{3} \mathrm{OH}\)

Myers' Psychology for AP 2
What do we call a mental predisposition that influences our interpretation of a stimulus? a. A context effect b. Perceptual set c. Extrasensory perception d. Emotion e. Motivation

Biology 8
The elongation ofthe leading strand during DNA synthesis a. progresses away from the replication fork. b. occurs in the 3'--->5' direction. c. produces Okazaki fragments. d. depends on the action of DNA polymerase. e. does not require a template strand.

Human Anatomy & Physiology 9
Define hypersensitivity. List three types of hypersensitivity reactions. For each, note whether antibodies or T cells are involved and provide two examples.

Principles of Economics 9
Which of the following is an example of a positive externality? a. Dev mows Myras lawn and is paid $100 for the service. b. Devs lawnmower emits smoke that Myras neighbor Xavier has to breathe. c. Myras newly cut lawn makes her neighborhood more attractive. d. Myras neighbor Xavier offers to pay her

Biochemistry 9
Consider the following in light of the concept of levels of structure (primary, secondary, tertiary, quaternary) as defined for proteins. (a) What level is shown by double-stranded DNA? (b) What level is shown by tRNA? (c) What level is shown by mRNA?

Biochemistry 9
In 1828, Whler was the first person to synthesize an organic compound (urea, from ammonium cyanate). How did this contribute, ultimately, to biochemistry?