how many moels of benzoic acid, a monoprotic acid with Ka = 6.4 x 10^-5 must be dissolved in 500. mL of water to make a solution with a pH=2.50

How many moles of al3+ ions are in 1.25 moles of al2o3

)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.

110 g of water (specific heat = 4.184 j/g c) and 100 g of a metal sample (specific heat = 0.397 j/g c) are heated from 25 degrees c to 75 degrees c. which substance required more thermal energy?