Which of the following is the best way to explain how baking a cake or frying an egg is a chemical change? A Both are changing size and shape.
B Heat is changing the texture of both substances.
C Heat is being added to both, causing a phase change.
D The end products of both cannot be reversed to their original forms.

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.