When of a certain molecular compound X are dissolved in of cyclohexane , the freezing point of the solution is measured to be . Calculate the molar mass of X.

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.