Question

The concentration of glucose, \({{\bf{C}}_{\bf{6}}}{{\bf{H}}_{{\bf{12}}}}{{\bf{O}}_{\bf{6}}}\) in normal spinal fluid is\(\frac{{{\bf{75mg}}}}{{{\bf{100g}}}}\). What is the molality of the solution?

Short answer

The molality of Glucose= 0.0042 molal

Step-by-step solution

Molality

Molality is also defined because of the number of moles of the solute present within the solvent in kilogram. It depends upon the concentration of the solution.

 Step 2: Molality of Glucose

Mass of \({{\bf{C}}_{\bf{6}}}{{\bf{H}}_{{\bf{12}}}}{{\bf{O}}_{\bf{6}}}{\bf{ = 75mg = 0}}{\bf{.075g}}\)

Molar Mass of \({{\bf{C}}_{\bf{6}}}{{\bf{H}}_{{\bf{12}}}}{{\bf{O}}_{\bf{6}}}{\bf{ = 180}}{\bf{.2g/mole}}\)

Number of Moles of \({C_6}{H_{12}}{O_6} = \frac{{0.075}}{{180.2}} = 0.00042mole\)

Mass of Solution= 100g

\({\bf{Molality = }}\frac{{{\bf{Number}}\,{\bf{of}}\,{\bf{Moles}}}}{{{\bf{Total}}\,{\bf{Mass}}\,{\bf{of}}\,{\bf{Solute}}\,{\bf{(kg)}}}}\)

Molality of \({C_6}{H_{12}}{O_6} = \frac{{0.00042}}{{100}} \times 1000 = 0.0042molal\)