Assignment Solutions CHEM 110- Fall 2011 1. Express the following ...

e) 5.00 gram of glucose (C 6 H 12 O 6 ) diluted to 250 mL
w
% =
v
mass of solute (g)
5.00 g
x 100 %w/v glucose = x 100 = 2.00 %
volume of solution (ml)
250 ml
Molarity =
mole of solute (g)
volume of solution (L)
Molarity ethanol =
1mole
5.00 g x
180 g
0.250 L
= 0.111 M
2. A solution is prepared by dissolving 12.15 gram of Nickel (II) nitrate in 175 mL of
water (density = 1.00 g/ml). Calculate:
a) the % w/w (mass percent)
mass of solution = 12.15 g Nickel + 175 g Nickel = 187.15 g solution.
w
% =
w
mass of solute (g)
mass of solution (ml)
12.15 g
x 100 %w/w Nickel = x 100 = 6.49 %
187.15 g
b) the mole fraction of Ni 2+ ions
Mole Nickel ions =
1mole
12.15 g x = 0.207 mole Ni
58.7g
2+
Mole of H 2 O = 175 g x
1mole
18 g
= 9.72 mole H
2
O
Mole fraction =
2+
mole of Ni
2+
mole of Ni + mole of
H
2
O
Mole fraction of Ni 2+ =
0.207 mole
0.207 mole + 9.72 mole
= 0.0209