Final answer:
To calculate the molality of glucose in spinal fluid with a concentration of 75 mg per 100 g, first convert the mass to grams and then to moles. With the molar mass of glucose and mass of solvent, calculate molality as moles of solute per kilogram of solvent. The solution has a molality of 0.00416 m.
Step-by-step explanation:
The question asks about calculating the molality of a glucose solution in spinal fluid where the concentration of glucose is 75 mg per 100 g of the solution. First, convert the mass of glucose to grams, which is 0.075 g. Next, because molality is moles of solute per kilogram of solvent, we need to find the moles of glucose.
The molar mass of glucose (C6H12O6) is approximately 180.16 g/mol. Therefore, the moles of glucose is 0.075 g / 180.16 g/mol = 0.000416 mol. The solvent (spinal fluid) has a mass of 100 g, or 0.1 kg. So, the molality is 0.000416 mol / 0.1 kg = 0.00416 m (mol/kg).