What mass of aluminum oxide will form when 15.0-g of oxygen combine with excess aluminum in a combination reaction that is 85.0% efficient?
4 Al + 3 O2 → 2 Al2O3

How much energy is made when a pice of wood burns. how do you know

The identities of substances are the same before and after which type of change

)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.