Answer is: value (number) is the same, units are different.
1) One carbon atom has mass of 12 amu (unified atomic mass). One unified atomic mass unit is approximately the mass of one nucleon (proton or neutron).
2) One mole of carbon atoms has mass of 12 g/mol. The mole is the unit (with the unit symbol: mol) of measurement for amount of substance. One mole of carbon atoms has 6.022·10²³ carbon atoms.
