Question

You need to make 3500 mL of a glucose solution with a concentration of 0.25 mol/L. What mass of glucose, C₆H₁₂O₆, will you need to dissolve in water?

Answer 1

$Volume\ (v) = 3500mL = 3.5L\\ concentration\ (c) = 0.25mol/L$

Using the formula,

$\begin{aligned} \textsf{number of moles} &= c ×V\\ &= 0.25× 3.5\\ &= 0.875 moles \end{aligned}$

note that the molar mass of glucose is 180 g/mol

$\begin{aligned}\textsf{mass } &= \textsf{number of moles}× \textsf{molar mass}\\ &= 0.875× 180 \\ &= 157.5g \end{aligned}$

Therefore, 157.5g of glucose, C₆H₁₂O₆, will be needed to dissolve in water.