# A solution of 6.42 g of a carbohydrate in 105.5 g of water has a density of 1.024 g/mL and an osmotic pressure of 4.61 atm at 20.0°C. What is the molar mass of the carbohydrate?

##### 1 Answer

This is a fairly challenging solution problem. I think the only way to solve this is to make the approximation I did. Definitely made me scratch my head!

Let's first find the molarity,

Then, we'll calculate the percent mass of the carbohydrate,

and assume we have one liter of solution, extrapolate the theoretical mass of the carbohydrate, and go from there,

of carbohydrate are theoretically in one liter.

Now, we know the molarity, so let's find the molar mass,

This is a very reasonable and I'm curious to see if anyone has any other ideas. Good question!