4. When 50.0 g of sulfur (S8) reacted in an experiment according to the following reaction, 56.7 g of Fe2S3 were produced. Calculate the percent yield for this reaction.

16Fe + 3S8 —-> 8Fe2S3

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

Amixture with the same composition throughout is!

)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.