Why is amu/atom = g/mole

Avogadro’s Number and the Mole 1 mol carbon = 12 g and 1 mol carbon = 6.022 x 1023 atoms So 12 g = 6.022 x 1023 atoms So for carbon the mass of 1 atom = 12 g / 6.022 x 1023 atoms = 1.99 x 10 - 23 g If we divide the mass of one atom of carbon by 12 to get the mass of 1 amu = 1.99 x 10 - 23 g / 12 = 1.66 x 10 – 24 g = 1 amu This relationship can be used as a conversion factor between amu and grams. The 1 is an exact value here because neither the 12 amu nor the 1 2 g were measured. We will use this on the next slide Very close to the mass of a proton/neutron (nucleon)

Why is it that atomic mass (amu/atom) = molar mass (g/mole)? Has to do with the definition of amu and mole (which are related) 1. Amu = mass of 1/12 atom of C – 12 1.660578 x 10 – 24 g/amu 2. Mole = # of atoms in 12 g of C – 12 6.022 x 1023 atoms/mole