Question

Calculate the mole fraction of each solute and solvent:

A. 0.710 kg of sodium carbonate (washing soda), Na₂CO₃, in 10.0 kg of water—a saturated solution at 0 °C

B. 125 g of NH₄NO₃ in 275 g of water—a mixture used to make an instant ice pack

C. 25 g of Cl₂ in 125 g of dichloromethane, CH₂Cl₂

D. 0.372 g of histamine, C₅H₉N, in 125 g of chloroform, CHCl₃

Answer 1

To calculate mole fractions, convert the mass of each component to moles, find the total number of moles in the solution, and then divide the number of moles of each substance by this total. Using this method, the mole fraction for NaCl and water in the given solution has been calculated.

Step-by-step explanation:

To calculate the mole fraction of a solute and solvent, follow these steps:

1. Convert the mass of each component to moles using its molar mass.
2. Add the moles of solute and solvent to find the total number of moles in the solution.
3. Divide the number of moles of each component by the total number of moles for their respective mole fractions.

For the mole fraction calculation of NaCl in water:

1. Convert 0.86 g NaCl to moles: 0.86 g NaCl / (58.44 g/mol) = 0.0147 mol NaCl.
2. Convert 1.00 x 10² g of water to moles: 1.00 x 10² g H₂O / (18.02 g/mol) = 5.55 mol H₂O.
3. Calculate the total moles: 0.0147 mol NaCl + 5.55 mol H₂O = 5.565 mol total.
4. Calculate the mole fractions: For NaCl (0.0147 mol / 5.565 mol) and for H₂O (5.55 mol / 5.565 mol).

The mole fraction for NaCl is 0.00264 and for water is 0.99736.