What is the molality of a solution which contains 20.0 g of cane sugar, C12H22O11 dissolved in125g of water?
To calculate the molality of a solution, you need to determine the number of moles of solute (cane sugar, C12H22O11) and the mass of the solvent (water).
First, you need to find the number of moles of cane sugar. The molar mass of cane sugar (C12H22O11) can be found by adding up the atomic masses of its constituent elements:
Molar mass of C12H22O11 = (12 * 12.01 g/mol) + (22 * 1.01 g/mol) + (11 * 16.00 g/mol) = 342.34 g/mol
Next, you can use the given mass of cane sugar (20.0 g) and the molar mass to calculate the number of moles:
Number of moles of cane sugar = Mass of cane sugar / Molar mass of cane sugar = 20.0 g / 342.34 g/mol
Now, you need to determine the mass of the solvent (water), which is 125 g.
Finally, to find the molality, divide the number of moles of the solute by the mass of the solvent:
Molality = Number of moles of solute / Mass of solvent = (20.0 g / 342.34 g/mol) / 125 g
Perform the calculations to find the molality.
mols sugar = grams/molar mass
m = mols/kg solvent