the mole fraction of urea (molar mass = 60g/mole) in a solution prepared by dissolving 16g of urea in 39g of h2o

moles urea = 16g/60

moles H2O = 39/18
mole fraction urea = moles urea/total moles.

thanks this will help me in solving my other problems...

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To find the mole fraction of urea in a solution, you need to calculate the number of moles of urea and the number of moles of water in the solution.

First, let's calculate the number of moles of urea:
Number of moles of urea = Mass of urea / Molar mass of urea

Given:
Mass of urea = 16g
Molar mass of urea = 60g/mol

Number of moles of urea = 16g / 60g/mol = 0.2667 mol

Now, let's calculate the number of moles of water:
Number of moles of water = Mass of water / Molar mass of water

Given:
Mass of water = 39g
Molar mass of water = 18g/mol

Number of moles of water = 39g / 18g/mol = 2.1667 mol

Next, to find the mole fraction of urea, we use the equation:
Mole fraction of urea = Moles of urea / Total moles of solute

Total moles of solute = Moles of urea + Moles of water

Total moles of solute = 0.2667 mol + 2.1667 mol = 2.4334 mol

Finally, we can calculate the mole fraction of urea:

Mole fraction of urea = 0.2667 mol / 2.4334 mol ≈ 0.1097

Therefore, the mole fraction of urea in the solution is approximately 0.1097.