A given mass of a gas occuples 919.0 mL in dry state at STP. The same main when collected over water at 15^(@)C and 750 mm pressure occupies one litre volume. Calculate the vapour pressure of water at 15^(@)C.

A given mass of a gas occuples 919.0 mL in dry state at STP. The same

1.	A given mass of a gas occuples 919.0 mL in dry state at STP. The same main when collected over water at 15^(@)C and 750 mm pressure occupies one litre volume. Calculate the vapour pressure of water at 15^(@)C.
Answer» <html><body><p></p>Solution :Step 1. To calculate the pressure of the dry gas at `15^(@)C` and <a href="https://interviewquestions.tuteehub.com/tag/750-335306" style="font-weight:bold;" target="_blank" title="Click to know more about 750">750</a> mm pressure<br/> `{:("Given Conditions at STP","Final Conditions"),(V_(1)=919 mL,V_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)=1000 mL),(P_(1)=760 mm,P_(2)=?("Dry state")),(T_(1)=273 K",",T_(2)=273+15=288 K):}` <br/> By applying gas <a href="https://interviewquestions.tuteehub.com/tag/equation-974081" style="font-weight:bold;" target="_blank" title="Click to know more about EQUATION">EQUATION</a>, we have `(760xx919)/(273)=(P_(2)xx1000)/(288)"or" P_(2)=(760xx919xx288)/(1000xx273)=736.7mm` <br/> Step 2. To Calculate the vapour pressure of water at `15^(@)C`.<br/> Vapour pressure of water =Pressure of the moist gas-Pressure of the dry gas, <br/> =750-736.7=13.3 mm <br/> Alternatively, if p is the vapour pressure of water at `15^(@)C`, then take `P_(2)`=(750-p)mm.Substituting in the equation, `(P_(1)V_(1))/(T_(2))=(P_(2)V_(2))/(T_(2))`, we get `(760xx919)/(273)=((750-p)xx1000)/(288)`. Solve for p.</body></html>