Which contains more molecules; a mole of chlorine gas (cl2 ) or a mole of glucose (c6h1206) ?

This is a tricky question. a mole of any compound contains the same number of molecules of that certain compound. so, one mole of chlorine gas has the same number of molecules as one mole of glucose, which is 6.02 x 10^23.

this is avogadro's number and it applies for any mole of molecules. 

the question is tricky because it is like asking. " what weighs more, a pound of feathers or a pound of rocks?" the both weigh the same, a pound. when ewe talking about moles, same as pounds, it is a quantity unit. one mole will aways be equal to 6.02 x 10^23 molecules.