Final answer:
To determine the mass of glucose to achieve a freezing point of -5.8°C in a water solution, use the concept of freezing point depression. Option B is correct.
Step-by-step explanation:
To find the mass of glucose needed to lower the freezing point of water to -5.8 °C, we use the concept of freezing point depression in colligative properties.
The freezing point depression (ΔTf) is calculated using the formula ΔTf = i × Kf × m, where i is the van't Hoff factor for glucose, which is 1 since glucose doesn't dissociate in solution, Kf is the freezing point depression constant for water (1.86 °C/kg/m), and m is the molality of the solution.
Firstly, we find the molality required to achieve a freezing point of -5.8 °C using the known values of ΔTf and Kf: m = ΔTf / (i × Kf). With the molality, we can calculate the moles of glucose required, and from there, convert to mass of glucose.
1. Calculate ΔTf given the desired freezing point depression
2. Calculate molality (m) = ΔTf / (i × Kf)
3. Calculate moles of glucose = molality (m) × kg solvent (water)
4. Calculate mass of glucose = moles × molar mass of glucose (180.2 g/mol)
Using this method, we find the mass of glucose necessary to create the desired solution. The correct answer is not provided in the information given, but this is the method that one would follow to arrive at the solution.
Calculate the molality needed for the desired ΔTf and convert moles to mass using the molar mass of glucose. Correct calculation would lead to the required mass.