Oxygen is present in a litre flask at a pressure of 7.6 × 10-10 mm Hg. The number of oxygen molecules in the flask at 0°C is:

Question

Oxygen is present in a litre flask at a pressure of 7.6 × 10-10 mm Hg. The number of oxygen molecules in the flask at 0°C is: (A) 2.7 × 109 molecules (B) 2.7 × 1010 molecules (C) 2.7 × 1011 molecules (D) 2.7 × 1012 molecules

Tardigrade Admin · Accepted Answer

PV= nRT n=(PV/RT) ⇒ (7.6×10-10/760)×(1/0.082×273) n=0.0446×10-12 The number of oxygen molecule =0.0446 ×10-12 NA ⇒ 2.7×1010

Q. Oxygen is present in a litre flask at a pressure of $7.6 \times 1 0^{- 10} mm H g$ . The number of oxygen molecules in the flask at $0^{\circ} C$ is:

$2.7 \times 1 0^{9}$ molecules

$2.7 \times 1 0^{10}$ molecules

$2.7 \times 1 0^{11}$ molecules

$2.7 \times 1 0^{12}$ molecules

$P V = n RT$
$n = \frac{P V}{RT}$
$\Rightarrow \frac{7.6 \times 1 0 ^{- 10}}{760} \times \frac{1}{0.082 \times 273}$
$n = 0.0446 \times 1 0^{- 12}$
The number of oxygen molecule
$= 0.0446 \times 1 0^{- 12} N_{A}$
$\Rightarrow 2.7 \times 1 0^{10}$

Q. Oxygen is present in a litre flask at a pressure of 7.6×10−10mmHg. The number of oxygen molecules in the flask at 0∘C is:

2.7×109 molecules

2.7×1010 molecules

2.7×1011 molecules

2.7×1012 molecules