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

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. Find the number of moles of atoms present in 28 g of N atoms. (Gram atomic mass of N = 14 g)

Q.

Calculate the mass of
(i) 10²² atoms of sulphur,
(ii) 0.1 mole of carbon dioxide.

[Atomic mass: S = 32, C = 12 and O = 16 and Avogadro's Number = 6 × 10²³]

Q. Fill in the following blanks :
(a) 1 mole contains ...................... atoms, molecules or ions of a substance.
(b) A mole represents an ..................... number of particles of a substance.
(c) 60 g of carbon element are ................... moles of carbon atoms.
(d) 0.5 mole of calcium element has a mass of ......................
(e) 64 g of oxygen gas contains ....................... moles of oxygen atoms.

Q.

What do you understand by Mole? If 8.4 g X element includes $9.03\times {10}^{22}$ atoms and 0.1 mol $X_2{Y}_3$ compound is 16g, find atomic mass of Y element. (Avogadro number is $6.02\times {10}^{23})$ [5 MARKS]