What is the molality of camphor in the solution.?

Question

Camphor is a natural compound from a tree found in Java, Brazil, China, and other countries. A solution of camphor in ethanol is a mild topical antiseptic. One such solution contains 1.60 g camphor dissolved in 137 mL of ethanol (ρ = 0.785 g/mL). What is:

1.molality of camphor in the solution.
______m

2.mole fraction of camphor in the solution

3.mass percent of camphor in the solution.
______percent

Answer 1

Camphor, C10H16O, MW=152.23 g/mol
Ethanol, C2H6O, MW=46.068 g/mol

1. Molality of camphor in the solution is 0.0977 mol/kg.
Solution:
moles camphor = 1.60g / 152.23 g/mol
moles camphor = 0.0105 mol

wt of ethanol in kg = (137mL * 0.785 g/mL) / 1000 g/kg
wt of ethanol in kg = 0.1075 kg

molality = 0.0105 mol / 0.1075 kg
molality = 0.0977 mol/kg

2. Mole fraction of camphor in the solution is 0.00449.
Solution:
moles camphor = 0.0105 mol

moles ethanol = 107.5g / 46.068g/mol
moles ethanol = 2.33 mol

total number of moles in the solution = 0.0105 mol + 2.33 mol
total number of moles in the solution = 2.3405 mol

mole fraction of camphor = 0.0105 mol / 2.3405
mole fraction of camphor = 0.00449

3. mass percent of camphor in the solution is 1.47%.
Solution:
wt of camphor = 1.60g
wt of ethanol = 107.5g
total wt = 1.60 + 107.5g
total wt = 109.1

mass percent of camphor = (1.60 * 100) / 109.1
mass percent of camphor = 1.47%

Answer 2

Camphor Solution

Answer 3

1. molality is moles of solute / kg. of solvent

Divide the 1.6 grams of camphor by its molecular mass to get moles. Convert the 137 mL of ethanol to grams using the density and then to kg. Divide the moles by the kg. to get molality.

2. Mole fraction. You have the moles of camphoe from above. Now calculate the moles of ethanol (you have the grams above as well). Total the moles together. Now you can calculate the mole fraction of camphor.

3. Mass percent is based on grams of each. Youhave those numbers above. Just total the mass and then you can calculate the mass % of camphor.