1. A 2.00 g sample of a particular compound was dissolved in 15.0 g of carbon tetrachloride. The boiling point of this solution was determined to be 77.85ºC.
For pure CCl4, TB = 76.50ºC and KB = 5.03°C·kg/mol
Calculate the boiling point elevation, ΔTB, for this solution.
2.Use the KB given in the problem information above and the boiling point elevation calculated in problem 1, calculate the molality of this solution (in mol solute/kg solvent)
3.Calculate the mass of the solvent (CCl4) in kg.
4.Use the molality calculated in question 2 and the solvent mass calculated in question 3 to determine the number of moles of solute present in this solution.
I don't believe you didn't know how to do any of this.
1. delta Tb = impure b.p.- pure b.p.
2. delta T = Kb*m
Substitute and solve for m.
3. Isn't the mass given in the problem. Convert to kg.
4. m = mols/kg solvent.
You know m and kg solvent, solve for mols
To answer these questions, let's go step by step:
1. The boiling point elevation, ΔTB, can be calculated using the formula:
ΔTB = KB * m
Where KB is the molal boiling point elevation constant and m is the molality of the solution. In this case, we have the value of KB from the problem information, which is 5.03 °C·kg/mol. We need to calculate the molality of the solution to determine ΔTB.
2. To calculate the molality of the solution, we need to know the amount of solute and solvent. In this case, we have a 2.00 g sample of the compound and 15.0 g of carbon tetrachloride (CCl4) as the solvent.
First, we need to convert the mass of both solute and solvent to moles. To do this, we divide the given mass by the molar mass of each substance. The molar mass of the compound needs to be known to do this step.
Second, we need to convert the amount of solute in moles to molality. Molality is defined as the moles of solute per kilogram of solvent. In this case, the molar mass of the solute is needed to complete these calculations.
3. To calculate the mass of the solvent, CCl4, in kg, we divide the given mass (15.0 g) by 1000 to convert it to kilograms.
4. Using the molality calculated in question 2 and the solvent mass calculated in question 3, we can determine the number of moles of solute present in the solution. Multiply the molality by the mass of the solvent in kg to get the number of moles of solute.
By following these steps, you should be able to calculate the boiling point elevation, molality, mass of solvent, and number of moles of solute for the given solution.