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42. The correct answer is (B). For the lighter elements, stable and non-radioactive nuclei have equal
numbers of protons and neutrons. In other words, the ratio of protons to neutrons is close to 1.
43. The correct answer is (E). There are approximately two moles of CuS available to react; for every
2 moles of CuS consumed 5.3 moles of NO will be produced. 5.3 moles 
× 30g/mole = 160g
44. The correct answer is (A). This compound has the greatest electronegativity difference between its
constituent atoms.
45. The correct answer is (C). The molecular weight of KMnO
4
is 158g/mole. 40g/158g/mole = .25 mole.

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Chemistry Subject Test
301
ARCO
■ SAT II Subject Tests
w w w . p e t e r s o n s . c o m / a r c o
46. The correct answer is (E). Remember that the greater the interactions between molecules in a
liquid, the higher the boiling point. Compound A, ethane, can only form van der Waals interactions
while compound C, acetic acid, can form two polar hydrogen bonds per molecule. Also, oxygen
forms more polar hydrogen bonds than sulfur.
47. The correct answer is (C). 0.2moles/liter 
× 0.5 liters + 1.6moles/liter × 0.2 liters = .1moles +
.32moles = .42moles. Final volume = 1 liter.
48. The correct answer is (D). The compound dissolves into (NH
4
)
+
and (NO
2
)
–
ions, where N = –3, H
= 1, N = 3, O = –2.
49. The correct answer is (B). Sodium yields a persistent yellow color in a flame test.
50. The correct answer is (E). The acid with the smallest dissociation constant is the weakest.
51. The correct answer is (A). A monounsaturated hydrocarbon has the general formula of CnH
2
ni;
C
3
H
6
fits this formula.