What is the mole fraction of 90 g of glucose (C6H12O6) dissolved in 900 g of water (H2O)?
Answer & explanation
Correct answer: option 4
Molar mass of C6H12O6 = 12 × 6 + 1 × 12 + 16 × 6 = 180 g mol–1 .
Moles of C6H12O6 = \(\frac{90}{180}\) = 0.5 mol
Moles of H2O = \(\frac{900}{18}\) = 50 mol
mole fraction of C6H12O6 = \(\frac{\text{moles of } C_6H_{12}O_6 }{\text{moles of} C_6H_{12}O_6 +\text{ moles of }H_2O }\)
mole fraction of C6H12O6 = \(\frac{0.5}{0.5+50}\)
mole fraction of C6H12O6 = \(\frac{0.5}{50.5}\)
mole fraction of C6H12O6 = 0.009