PART C
Directions
Each of the incomplete statements or questions below is followed by five suggested
completions or answers. Select the one that is best for each case.
24 . Which of the following is a Lewis base?
(A) NH 4 +
(B) CH 4
(C) PH 3
(D) CH 3 CH 3
(E) HCl
25 . When one mole of sulfur burns to form SO 2 , 1,300 calories are released. When one mole of
sulfur burns to form SO 3 , 3,600 calories are released. What is the ΔH when one mole of SO 2
is burned to form SO 3?
(A) 3,900 cal
(B) −1,950 cal
(C) 1,000 cal
(D) −500 cal
(E) −2,300 cal
26 . How many atoms are in a 36.5 g sample of SF 6 gas?
(A) 1.51 × 10^22
(B) 1.06 × 10^22
(C) 1.51 × 10^23
(D) 1.06 × 10^24
(E) 1.51 × 10−24
