ACS Practice Test 1 Questions and Correct Answers

ACS Practice Test 1 Questions and
Correct Answers
Which molecule has the greatest bond energy?
(A) H—Br
(B) H—F
(C) H—At
(D) H—Cl
(E) H—I CORRECT ANSWER: (B) H—F

For which process is the entropy change per mole the largest at constant temperature?
(A)H2O(l) → H2O(g)
(B)H2O(s) → H2O(g)
(C)H2O(s) → H2O(l)
(D)H2O(l) → H2O(s) CORRECT ANSWER: (B)H2O(s) → H2O(g)

Under which conditions does nitrogen have the largest entropy per mole?
(A) N2(s) at 50 K and l atm (B) N2(l) at 70 K and l atm
(C) N2(g) at 80 K and 1 atm
(D) N2(g) at 80 K and 0.5 atm CORRECT ANSWER: (D) N2(g) at 80 K and 0.5 atm

In which process is entropy decreased?
(A)dissolving sugar in water
(B)expanding a gas
(C)evaporating a liquid
(D)freezing water CORRECT ANSWER: (D)freezing water

Which reaction has the largest positive entropy change per mole of product formed?
(A) S(s) + 3F2(g) → SF6(g)
(B) SO2(g) + Na2O(s) → Na2SO3(s)
(C) Fe3+(aq) + SCN-(aq) → FeSCN2+(aq)
(D) H2O(l) → H2O(g) CORRECT ANSWER: (D) H2O(l) → H2O(g)

The nucleus of which atom contains seven neutrons?
Atom A n = 1 n = 2 n = 3
M = 24,Z = 12 2e - 8e - 2e -

Atom B n = 1 n = 2 n = 3
M = 15,Z = 7 2e - 5e -

Atom C n = 1 n = 2 n = 3
M = 17,Z = 10 2e - 8e -

Atom D n = 1 n = 2 n = 3

, M = 7, Z = 3 2 e - 1 e -

Atom E n = 1 n = 2 n = 3
M = 34,Z = 17 2e - 8e - 7e -

(A) A
(B) B
(C) C
(D) D
(E) E CORRECT ANSWER: (C) C,
Atom C n = 1 n = 2 n = 3
M = 17,Z = 10 2e - 8e -

In which pair of compounds should the first member be more covalent than the second
member?
(A) TlCl, TlCl3
(B) SnI4, SnF4
(C) LiF, BF3
(D) SnF4, CF4 CORRECT ANSWER: (B) SnI4, SnF4

Which is the most complete and best description of a covalent bond?
(A)a system of two nuclei with a pair of electrons located exactly midway between both
nuclei
(B)the attractive force between two atoms of opposite charge
(C)a donor bond in which one atom donates an unshared pair to the other
(D)a system of two nuclei where each atom donates one electron to the other atom, thus
forming a bond CORRECT ANSWER: (D)a system of two nuclei where each atom
donates one electron to the other atom, thus forming a bond

Which pair of elements is most likely to react to form a covalently bonded species?
(A) P and O
(B) Ca and O
(C) K and S
(D) Zn and C CORRECT ANSWER: (A) P and O

Which chloride should exhibit the most covalent type of bond?
(A) NaCl
(B) KCl
(C) CaCl2
(D) BaCl2
(E) BeCl2 CORRECT ANSWER: (E) BeCl2

The compound of which two elements is most likely to involve covalent bonding?
Electronegativities of Unknown Elements
Q 0.9 X 3.0
R 1.0 Z 4.0
T 2.8