molarity is defined as the number of moles of solute in 1 L of solvent
number of moles of glucose = mass of glucose present / molar mass of glucose
number of glucose moles = 5.10 g / 180 g/mol = 0.0283 mol
there are 0.0283 mol in 100.5 mL water
we need to find the number of glucose moles in 1000 mL
therefore in 1000 mL there are - 0.0283 mol / (100.5 x 10⁻³ L) = 0.282 mol/L
molality of solution - 0.282 M
