The law of conservation of matter states that matter is neither created nor destroyed in a chemical reaction. Which of the following must be true? * A the mass of the products is greater than the mass of the reactants
B the mass of the products is less than the mass of the reactants
C the mass of the reactants must equal the mass of the products

)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.