[haay]

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What mass of K2CO3 is needed to prepare 200. mL of a solution having a potassium ion concentration of 0.150 M?

A. 4.15 g
B. 10.4 g
C. 13.8 g
D. 2.07 g
E. 1.49 g


2. A 50.0 mL sample of 0.436 M NH4NO3 is diluted with water to a total volume of 250.0 mL. What is the ammonium nitrate concentration in the resulting solution?

A. 21.8 M
B. 0.459 M
C. 2.18  10-2 M
D. 8.72  10-2 M
E. 0.109 M

What volume, in mL, of a 3.89 x 10-2 M solution is required to provide 2.12 g of KBr?
(Atomic weights: K = 39.10, Br = 79.90).
a) 520
b) 458
c) 389
d) 325
e) 425
(18) Of the following, the only empirical formula is:
(A) C3H6
(B) Na2S2O8
(C) C8H8O3
(D) O3

(23) The mass of one molecule of fluorine gas is about:
(A) g

(B) g

(C) g