If 1030 g of a potassium citrate is dissolved in 2320 g of water solvent, calculate the freezing temperature (if below 0 oC, include the sign) of the solution. Consider if the solute is an electrolyte.
Kf (oC/m) 1.858
This is done the same way but delta T = i*Kf*m
i will be 2 since potassium citrate dissociates into two ions. .
moles K citrate = grams/molar mass.
molality = moles K citrate/2.32 kg solvent.
Then plug into the first equation and calculate delta T. Use that to obtain the final T.
is the answer 5.38???
this assignement is due in less than 20 min and i need an answer
Sorry, I went to bed last night. It was WAY past my bed time. I worked the problem and obtained delta T = 5.49 which is close to you 5.48. Probably just a rounding error BUT the answer is -5.49. Since delta T is 5.49, and the regular freezing point is 0, then delta T = 0-T
5.49 = 0-T
T = -5.49.
To calculate the freezing temperature of the solution, we need to consider two main factors: the molality of the solution and the cryoscopic constant (Kf) for the solvent.
First, we need to determine the molality of the potassium citrate solution. Molality (m) is defined as the number of moles of solute per kilogram of solvent. We have the mass of the solute (1030 g) and the mass of the solvent (2320 g), so we can calculate the molality as follows:
Molality (m) = moles of solute / mass of solvent (in kg)
To find the moles of solute, we need to use the molar mass of potassium citrate. The molar mass of potassium citrate (K3C6H5O7) is calculated by multiplying the atomic masses of each element by the number of moles for that element and summing them up. The molar mass of potassium citrate is approximately 306.39 g/mol.
Moles of solute = mass of solute / molar mass of potassium citrate
Plugging in the values:
Moles of solute = 1030 g / 306.39 g/mol
Next, we need to convert the mass of the solvent from grams to kilograms:
Mass of solvent (in kg) = 2320 g / 1000
Now we can calculate the molality:
Molality (m) = moles of solute / mass of solvent (in kg)
Now that we have the molality, we can use the cryoscopic constant (Kf) for water to calculate the freezing temperature depression. The formula to calculate the freezing temperature depression is:
ΔT = - Kf * m
Plugging in the values for Kf and the calculated molality, we can find the freezing temperature:
ΔT = -1.858 oC/m * molality