A student was asked to demonstrate a chemical change to the class. A candle was lit and as it burned the student explained that the shorter length was evidence of a chemical change. This explanation is not complete. The student should also include which of the following in his explanation? A. Color change
B. Solid formation
C. Heat given off
D. Heat taken in

)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.