What is the boiling point of the solution in which you are going to cook spaghetti if it contains 51.0 g of NaCl dissolved in 1.30 L of water? Assume the density of water is 1.00 g/mL. Use molar masses with at least as many significant figures as the data given. Enter your answer with two decimal places.
moles NaCl = grams/molar mass
Solve for moles NaCl.
molality = moles NaCl/kg solvent
Solve for molality (kg solvent = 1.30).
delta T = i*Kb*molality
You have i = 2, Kb, and molality. Solve for delta T, then add that to 100 C to find the boiling point.
what's Kb?
Isn't that 0.512 degrees C/m? I think so.
To find the boiling point of the solution, we need to use the equation for boiling point elevation, which is given by:
ΔTb = Kb * m
Where:
ΔTb is the boiling point elevation
Kb is the molal boiling point constant of the solvent (water)
m is the molality of the solute (NaCl)
First, let's calculate the molality of the solute:
Molality (m) = moles of solute / mass of solvent (in kg)
First, we need to find the moles of NaCl:
moles of NaCl = mass of NaCl / molar mass of NaCl
The molar mass of NaCl is 58.44 g/mol (as per the periodic table).
moles of NaCl = 51.0 g / 58.44 g/mol = 0.874 mol
Next, we need the mass of the solvent in kg:
mass of solvent = volume of water * density of water
Since the volume of water is given in liters, we need to convert it to kg using the density of water. The density of water is 1.00 g/mL or 1.00 kg/L.
mass of solvent = 1.30 L * 1.00 kg/L = 1.30 kg
Now we can calculate the molality:
m = 0.874 mol / 1.30 kg = 0.672 mol/kg
Next, we need to find the molal boiling point constant (Kb) for water. The molal boiling point constant for water is 0.512°C/m.
Now we can calculate the boiling point elevation (ΔTb):
ΔTb = Kb * m = 0.512°C/m * 0.672 mol/kg = 0.344064°C
Finally, we need to determine the boiling point of water. The boiling point of pure water at sea level is 100°C.
Boiling point of the solution = Boiling point of pure water + ΔTb
Boiling point of the solution = 100°C + 0.344064°C = 100.34°C
Therefore, the boiling point of the solution in which you are going to cook spaghetti is 100.34°C.