Xylose is a compound that has five carbon atoms in each molecule and contains 40% carbon by mass - VCE - SSCE Chemistry - Question 3 - 2008 - Paper 1

Since xylose has 5 carbon atoms, the molar mass of carbon (C) is approximately 12 g/mol. Therefore, the total mass of carbon in xylose is:

$ext{Mass of 5 Carbon Atoms} = 5 imes 12 = 60 ext{ g/mol}$

Equating the mass of carbon derived from the total molar mass to the actual mass of carbon gives us:

$0.4M = 60$

To find M, solve the equation:

M = rac{60}{0.4} = 150 ext{ g/mol}

Thus, the molar mass of xylose is determined to be 150 g/mol, which corresponds to option C in the list.