Question

2.82 g of glucose are dissolved in 30 gram of water. Calculate-
1) The molality
2) Mole fraction of water

Answer 1

given mass of solute= 2.82 g

then, no. of moles = 2.82/180

=0.0156 moles

now, 1) molality = 0.0156 x 1000/30

= 0.52 molal

2) mole fraction of water = no. of moles of water/ no. of moles of water + no. of moles of glucose

= 1.66/1.66 +0.0156

= 0.990