4. why can't the subscripts be changed in a chemical equation in chemistry

How many atoms are there in 5.70 mol of mg

If 90.0 grams of ethane reacted with excess chlorine,how many grams of dicarbon hexachloride would form

)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.