A sample of hydrogen gas was collected over water at 21° C and 685mmHg . The volume of the container was 7.80L . Calculate the mass of H2(.g.) collected (vapour pressure of water =18.6mmHg at 21° C )

Question

A sample of hydrogen gas was collected over water at 21° C and 685mmHg . The volume of the container was 7.80L . Calculate the mass of H2(.g.) collected (vapour pressure of water =18.6mmHg at 21° C ) (A) 0.283g (B) 0.570g (C) 0.589g (D) 7.14g

Tardigrade Admin · Accepted Answer

The volume of H2 at STP V2=(P1 V1/T1)× (T2/P2) Here vapour pressure of H2 at 21° C = 685 mm &ndash; 18.6 mm = 666.4 mm So V2=(666 .4 mm Hg × 7 . 80 L × 273 K/294 K × 760 mm)=6.38 L At STP 22.4 L H2 weight=2 g So, at STP 6.38 L H2 weigh= (2 g × 6 . 38 L/22 . 4 L)=0.570 g

Q. A sample of hydrogen gas was collected over water at $2 1^{\circ} C$ and $685 mm H g$ . The volume of the container was $7.80 L$ . Calculate the mass of $H_{2} (g)$ collected (vapour pressure of water $= 18.6 mm H g$ at $2 1^{\circ} C$ )

$0.283 g$

$0.570 g$

$0.589 g$

$7.14 g$

Q. A sample of hydrogen gas was collected over water at 21∘C and 685mmHg . The volume of the container was 7.80L . Calculate the mass of H2​(g) collected (vapour pressure of water =18.6mmHg at 21∘C )

0.283g

0.570g

0.589g

7.14g

The volume of H2​ at STP V2​=T1​P1​V1​​×P2​T2​​ Here vapour pressure of H2​ at 21∘C = 685 mm – 18.6 mm = 666.4 mm So V2​=294K×760mm666.4mmHg×7.80L×273K​=6.38L At STP 22.4LH2​weight=2g So, at STP 6.38LH2​weigh=22.4L2g×6.38L​=0.570g

Q. A sample of hydrogen gas was collected over water at $2 1^{\circ} C$ and $685 mm H g$ . The volume of the container was $7.80 L$ . Calculate the mass of $H_{2} (g)$ collected (vapour pressure of water $= 18.6 mm H g$ at $2 1^{\circ} C$ )

$0.283 g$

$0.570 g$

$0.589 g$

$7.14 g$