A mixture is prepared that is 5.0% (w/w) of an
unknown substance mixed with naphthalene (molar
mass = 128.2 g mol 1). The freezing point of this
mixture is found to be 77.3 °C. What is the molar
mass of the unknown substance? (The melting point
of naphthalene is 80.2 °C and K₁ = 6.9 °C m¯¹.)
The molar mass of the unknown substance =
i
g mol-1