Question

A solution was prepared by dissolving 150.0 g of kcl in 295 g of water. calculate the mole fraction of kcl. (the formula weight of kcl is 74.6 g/mol. the formula weight of water is 18.0 g/mol.) express the mole fraction of kcl to two decimal places.

Answer 1

The mole fraction of KCl in the solution is calculated by dividing the number of moles of KCl (2.01) by the total moles (KCl + water), which gives approximately 0.11.

Step-by-step explanation:

The student's question is about calculating the mole fraction of KCl in a solution. The first step is to calculate the number of moles of KCl and water. With the formula weight of KCl being 74.6 g/mol, we have:

1. Moles of KCl = mass of KCl / molar mass of KCl = 150.0 g / 74.6 g/mol = 2.01 moles
2. Moles of water (H2O) = mass of water / molar mass of water = 295 g / 18.0 g/mol = 16.39 moles
3. The mole fraction of KCl is calculated by taking the moles of KCl divided by the total moles of the solution (KCl + water). Mole fraction of KCl = moles of KCl / (moles of KCl + moles of water) = 2.01 / (2.01 + 16.39) ≈ 0.11.

Therefore, the mole fraction of KCl in the solution, to two decimal places, is approximately 0.11.

Answer 2

calculate the mole of KCl and water
moles of KCl= 150g/74.6g/mol= 2.01 moles
moles of water= 295g/18g/mol=16.39 moles
calculate the total number of moles
2.01 +16.39 =18.4 moles
moles fraction of KCl is therefore=2.01/18.4= 0.11mole