& 9. & Which statement is incorrect? & & & A. & One mole contains 6.02 1023 molecules. & & & B. & One molar mass equals one mole. & & & C. & One mole equals 6.02 1023 g of a compound. & & & D. & One mole of water contains the same number of molecules as one mole of carbon & & & & & & & & & & & & & & & & & & & dioxide.
A, D is correct and C is definitely the false statement. One mole is equivalent to 6.02x1023 atoms or molecules. It's a measurement similar to "a dozen" because it only refers to the number of something, i.e. a dozen eggs and a dozen cows are two very different things except that there's 12 of them. So a mole of carbon is 6.02x1023 carbon atoms, and a mole of water is 6.02x1023 water molecules, even though a carbon atom and a water molecule weigh different amounts, are different in size, etc. About B (true), n = m/Mw where n - amount (moles) and Mw -molecular weight, m is mass.