Which of the following has highest mass

Q. (a) What is meant by 'a mole of carbon atoms' ?
(b) Which has more atoms, 50 g of aluminium or 50 g of iron ? Illustrate your answer with the help of calculations.
(Atomic masses : Al = 27 u ; Fe = 25 u)

Q. Which of the following has least mass: 2 g atom of nitrogen, 3*10^23 atoms of C, 1 mole of S, 7 g of Ag?

Q. Which of the following elements has the same molecular mass as its atomic mass ?
(a) nitrogen
(b) neon
(c) oxygen
(d) chlorine

Q. Which has the highest mass ?
(a) 50 g iron (b) 5 moles of $N_2$
(c) 0.1 mol atom of Ag (d) ${10}^{23}$ atoms of carbon