The formula and the molecular weight of an inknown hydrocarbon compund are to be determined by element analysis and the freezing-point depressing method.
A) the hydrocarbon is found to contain 94.78 percent carbon anf 5.22 percwnt hydrogen. CALCULATE the empirical formula of the unknown hydrocarbon.
B) A solution is prepared by dissolving 2.53 grams of p-dichlorobenzene (molar mass 147 g/mol) in 25.86 grams of naphthalene (molar mass 128.2 g/mol). CALCULATE the molality of the p-dichlorobenzene solution.
C) The freezing point of pure naphthalene is determined to be 80.2 Degree Celsius. The solution prepared in (b) is found to have an initial freezing point of 75.7 Degree Celsius. Calculate the lolal freezing-point depression constant of naphthalene.
D) A solution of 2.40 grams of the unknown hydrocarbon dissolved in 26.7 grams of naphthalene is found to freeze initialy at 76.2 Degree Celsius. Caluculate the apparent milar mass of the unknown hydrocarbon on the basis of the freezing-point depression experiment above.
E) WHAT is the molecular formula of the unknown hydrocarbon?