Question

Juice (d=1.0g/mL) from freshly harvested grapes has about 24% sucrose by mass. What is the molality of sucrose in the grape juice after 25% by mass of the water content has been removed? Assume a volume of 15.0 L.

Answer 1

1. calculate how many g of sucrose you have in the juice before concentrate (15000mL x 0.24 g/mL)
2. calculate the final volume of the juice after concentrate (15mL-(15mL x 0.25))
3. find the molecular mass of sucrose (MM= 342.2965 g/mol)
4. calculate the moles of sucrose (n=m/MM) (15000mL x( 0.24 g/mL ) /(342.2965 g/mol))
5. calculate the molarity dividing the moles of sucrose by the volume of the concentrate in L ( M= n/L)