Respuesta :
Take into account that partial pressure is given by:
[tex]P=n(\frac{RT}{V})=n\cdot\text{constant}[/tex]Furthermore, consider that the total pressure is the sum of the partial pressure of each gas. In this case, you have:
[tex]P_{\text{tot}}=P_1+P_2[/tex]where P1 is the partial pressure of NO2 and P2 is the partial pressure due to Ne.
Then, use the information about total pressure and partial pressure of Ne to get partial pressure of NO2:
[tex]P_1=P_{\text{tot}}-P_2=1.19\text{bar-}0.25\text{bar}=0.94bar[/tex]Next, use the expression for the partial pressure to determine the value of the constant, by using the information about NO2, as follow:
[tex]\text{constant}=\frac{P_1}{n}=\frac{0.94\text{bar}}{0.507\text{mol}}=\frac{1.85bar}{mol}[/tex]Next, use the same expression to calculate the value of n for Ne:
[tex]n^{\prime}=\frac{P_2}{\text{constat}}=\frac{0.25\text{bar}}{1.85\frac{bar}{\text{mol}}}=0.135mol[/tex]Then, there are 0.135mol of Ne in the flask. To determine this mass in grams, use the atomic mass, as follow:
[tex]M=(0.135mol)\cdot(\frac{20.1797g}{mol})=2.72g[/tex]Hence, there are 2.72g of Ne in th flask
