Question: how many atoms are in a mole of barium chloride?
Answer: Explanation: If I asked how many atoms there were in a dozen formula units of BaCl2 , I think you would quickly answer 3 dozen: 12 barium atoms, and 24 chlorine atoms. The question specified molar quantities, and the mole is just another number, admittedly a very large number, i.e. NA = 6.022×1023 mol−1 .