What is the weight of one mole Carbon atoms?

By definition, one mole of an element has a mass in grams equal to its relative atomic mass. The atomic mass of Carbon ($\text{C}-12$ isotope) is exactly $12$ atomic mass units ($\text{amu}$).Therefore, the molar mass of Carbon is $12\text{g/mol}$, meaning that $1$ mole of Carbon atoms weighs exactly $12\text{gm}$.