In order to calculate the percentage of a substance (sucrose this time) in a sample of known mass, the mass of the substance needs to be determined first.
The mass of a substance can be determined from its number of moles and molar mass, such that:
mass = mole x molar mass
Once the mass of the substance is determined, the percentage of the substance in 20.0 g sample can be calculated as:
Percentage of substance = mass of substance/mass of sample x 100
Hence, assuming that the mass of sucrose is x g:
percentage of sucrose in the sample = x/20 X 100
= 5x %
More on percentage calculation can be found here: https://brainly.com/question/12616082
