How many grams of CaCl2 are needed to make 644.5 g of a solution that is 29.0 % (m/m) CaCl2 in water

How many miles of water are produced if 5.43 mol pbo2 are consumed

)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.

At stp, which substance is the best conductor of electricity? a. nitrogen b. neon c. sulfur d. silver