A solution of NaCl and glucose gives a freezing point of -0.95°C. It contains 140 mOsmol glucose/L. Give concentration of NaCl in milliosmoles per liter and molarity. Thanks
freezing dpr drepression=-1.8*(140+x)
solve for X
Molarity=X/2
Sweet! I was on the right track! Thanks man!
To find the concentration of NaCl in milliosmoles per liter and molarity, we can use the information about the freezing point depression and the known concentration of glucose.
1. Determine the van't Hoff factor (i) for the NaCl. The van't Hoff factor represents the number of particles that a substance dissociates into when it dissolves in water. For NaCl, it fully dissociates into two ions (Na+ and Cl-), so the van't Hoff factor for NaCl is 2.
2. Calculate the moles of glucose dissolved in the solution. From the given information, we know that the solution contains 140 mOsmol of glucose per liter. Since each glucose molecule represents one osmol, the moles of glucose can be calculated as follows:
Moles of glucose = 140 mOsmol/L
3. Calculate the concentration of glucose in moles per liter (Molarity). Since we know the moles of glucose and the volume of the solution, we can calculate the molarity using the following formula:
Molarity (M) = Moles of solute / Volume of solution (in liters)
Given that the volume is not specified, we assume it to be 1 liter for convenience:
Molarity of glucose = Moles of glucose / Volume of solution = 140 mOsmol/L
4. Determine the molality of the solution using the freezing point depression (∆Tf). The freezing point depression is the difference between the freezing point of a pure solvent and the freezing point of the solution. In this case, the freezing point depression (∆Tf) is given as -0.95°C.
The equation relating ∆Tf to the molality (m) is:
∆Tf = (i * Kf * m)
Where:
i = van't Hoff factor (2 for NaCl)
Kf = cryoscopic constant of the solvent (water, usually 1.86 °C/molal)
m = molality (moles of solute per kilogram of solvent)
Rearrange the equation to solve for molality (m):
m = ∆Tf / (i * Kf)
Plugging in the given values:
m = -0.95°C / (2 * 1.86 °C/molal)
5. Calculate the moles of NaCl in the solution using the molality (m) and assuming 1 kg of water. Since the molality represents the moles of solute per kilogram of solvent, we can calculate the moles of NaCl using the following formula:
Moles of NaCl = molality * kg of water(moles of solute) = m * 1 kg
6. Finally, determine the concentration of NaCl in milliosmoles per liter:
Concentration of NaCl (milliosmoles per liter) = (Moles of NaCl * van't Hoff factor * 1000) / Volume of solution
Also, calculate the molarity of NaCl using the following formula:
Molarity of NaCl = Moles of NaCl / Volume of solution (in liters)
Remember to convert temperature from Celsius to Kelvin, if needed, for the calculations.
I hope this helps! Let me know if you have any further questions.