Question

Question #2e157

Answer 1

Dissolve 2.25 grams of glucose in 250 milliliters solvent.

Explanation:

To get the weight of glucose to be dissolved in solvent (usually water), first you must do the following computations:

(1) Convert the given volume from milliliters (mL) to liters (L).

`250 cancel "mL"` x `"1 L"/(1000 cancel "mL")` = `"0.250 L"`

(2) Convert the given number of Liters to number of moles (mol) using the given molar concentration (unit is moles per Liter solution).

`0.250 cancel "L"` x `(0.05 "mol")/(1 cancel "L")` = `"0.0125 mol"`

(3) Convert computed number of moles to number of grams (g) using the molecular weight of the substance.

`0.0125 cancel "mol"` x `(180 g)/(1 cancel "mol")` = `"2.25 g"`

Therefore, in order to get a 0.05 molar solution, you must dissolve 2.25 grams of glucose in 250 milliliters solvent.

Here is a video that explains in details how to prepare a solution in the lab:
Lab Demonstration | Solution Preparation & Dilution.