Question

How would you prepare each of the following solutions?
(a) A 0.150 M solution of glucose in water
(b) A solution of KBr in water
(c) A solution of methyl alcohol (methanol) and water in
which Xmethanol = 0.15 and Xwater = 0.85

Answer 1

a) A 0.150 M solution of glucose in water

0.15 = w/180*1/1

w = 0.15*180 = 27 grams

Dissolve 27 grams of glucose in 1 litre water . so that 0.15 M glucose can be prepared.

(b) A solution of KBr in water

no concentration is given

(c) A solution of methyl alcohol (methanol) and water in
which Xmethanol = 0.15 and Xwater = 0.85

Xch3oh/Xwater = 0.15/0.85 = 0.1764

so that ratio of Xch3oh:xwater = 0.1764:1

0.1764 mol of ch3oh mix with 1 mol water

so that 5.64 grams of ch3oh dissolved in 18 grams of water