Q: Find the approx number of molecules contained in a vessel of volume 7 litres at 0°C at 1.3 × 10^{5} pascal

(a) 2.4 × 10^{23}

(b) 3 × 10^{23}

(c) 6 × 10^{23}

(d) 4.8 × 10^{23}

Ans: (a)

Sol: P V = n R T

$\large n = \frac{P V}{R T} $

Number of molecules , N = n N_{A} ; Where N_{A} = Avogadro’s Number