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calculate the number of particles in the following:

(a)69 g of Na atoms. (b)56 g of He (c) 0.1 mole of atom.

^{-1}

23 g of sodium contains = 6.022$\times $10

^{23}particles

69 g of sodium = $\frac{6.022\times {10}^{23}}{23}\times 69$ = 18.066$\times $10

^{23}particles

2) Molar mass of helium = 4 g mol

^{-1}

4 g of He contains = 6.022$\times $10

^{23}particles

56 g of He contains = $\frac{6.022\times {10}^{23}}{4}\times 56$ = 84.308$\times $10

^{23}particles

3) 1 mole of atom contains = 6.022$\times $10

^{23}particles

0.1 mole contains = 6.022$\times $10

^{23}$\times $0.1 = 6.022$\times $10

^{22}particles

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