Answers to Solute Concentration Problems

1. To prepare a 5% glucose solution, weigh out 5 grams of glucose and add water until you have 100 mls of solution (5 grams per 100 mls).

2. To prepare a 0.5 M solution weight out 0.5 moles of glucose. One mole of glucose is 180 grams, so 0.5 moles of glucose would be 90 grams (180 g/mole X 0.5 mole = 90 g). Then, add water until you have 1 liter of solution (0.5 moles/liter).

3. The osmolarity of a 0.15 Molar solution of NaCl is 0.3 Osmolar. Since NaCl splits into 2 ions (particles) when it dissolves, the osmolarity is 2 times the molarity (0.15 M x 2 Osm/M = 0.30 Osm).

4. There are 18 grams in 0.1 mole of glucose. The molecular weight of glucose is 180 g/mole, therefore 180g/mole X 0.1 mole = 18 grams.

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