when 5.0 g of CaCl2 is dissolved in 50 g of water, how do you get the boiling temperature of 101.5 degree c
To determine the boiling temperature of the solution, you need to consider the effect of the dissolved CaCl2 on the boiling point of water. This effect is known as boiling point elevation.
Boiling point elevation occurs because the addition of solutes, such as CaCl2, increases the boiling point of the solvent, in this case, water. The magnitude of the boiling point elevation depends on the concentration of the solute.
To calculate the boiling temperature, you can use the following formula:
ΔTb = Kb * m
Where:
ΔTb = boiling point elevation
Kb = molal boiling point elevation constant for water (0.512 °C/m)
m = molality of the solution
First, we need to calculate the molality of the solution. Molality is defined as the number of moles of solute per kilogram of solvent.
Molar mass of CaCl2 = 40.08 g/mol + (2 * 35.45 g/mol) = 110.98 g/mol
Number of moles of CaCl2 = mass of CaCl2 / molar mass of CaCl2
= 5.0 g / 110.98 g/mol
Next, we calculate the mass of water in kilograms:
Mass of water = 50 g / 1000
= 0.05 kg
Molality (m) = moles of solute / mass of solvent in kg
= moles of CaCl2 / mass of water in kg
Finally, substitute the values into the formula:
ΔTb = 0.512 °C/m * m
Now, you can calculate the boiling temperature by adding the boiling point elevation to the normal boiling point of water, which is 100 °C:
Boiling temperature = 100 °C + ΔTb
By plugging in the values calculated above, you can find the boiling temperature.