Enzymes are large molecules that are present in most living things and are needed in order to ensure that various chemical
reactions occur quickly. Some enzymes contain metal atoms,
such as copper or magnesium, which are important to their
function. What field of chemistry does this belong to?

Which terms are used to identify pure substances

)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.

Which fossil fuel is mainly used for heating and cooking? a. electricity b. coal c. petroleum d. natural gas