A student placed 10.5g of glucose (C6H12O6) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.- mL mark on the neck of the flask was reached. The flask was then shaken until the solution was uniform. A 20.0-mL sample of this glucose solution was diluted to 0.500 L. How many grams of glucose are in 100mL. of the final solution?

Question

A student placed 10.5g  of glucose (C6H12O6) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.- mL mark on the neck of the flask was reached. The flask was then shaken until the solution was uniform. A 20.0-mL sample of this glucose solution was diluted to 0.500 L. How many grams of glucose are in 100mL. of the final solution?

answer in Grams

DrBob222 · Answer

10.5 g/100 mL = 0.105 g/mL.
You took 20 mL which contains 20 x 0.105 g/mL.
Now you diluted that 20 to 500 so the 500 now contains 20 x 0.105 g/mL = 2.10 g so you now have 2.10/500 mL = 0.00420 g/mL. How much is in 100 mL of that solution?