Question

A solution was prepared by dissolving 200.0 g of KCI in 215 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

Answer:mole fraction of KCl = 0.18

Step-by-step explanation:

no of moles of KCl = Mass/Molar mass

where mass (weight) of KCl = 200.0g

molar mass of KC1= 74.6g/mol

= 200/74.6 = 2.68 moles

no of moles of H2O = Mass/Molar mass

where mass (weight) of water = 215.0g

molar mass of water = 18.0g/mol

= 215/18 = 11.94moles

mole fraction of KCl = no of moles of KCl/(no of moles KCl + no of moles of H2O(water))

= 2.68/(2.68+ 11.94)

= 2.68/14.62 = 0.18