Respuesta :
Answer:
[tex]\boxed{\text{3.6 atm}}[/tex]
Explanation:
For this question, we must use Dalton's Law of Partial Pressures:
The partial pressure of a gas in a mixture of gases equals its mole fraction times the total pressure:
[tex]p = \chi p_{\text{tot}}[/tex]
1. Calculate the number of moles of each gas.
[tex]n_{\text{CO}_{2}} = \text{35.07 g} \times \dfrac{\text{1 mol}}{\text{44.01 g}} = \text{0.7969 mol}\\\\n_{\text{H}_{2}\text{O}} = \text{27.93 g} \times \dfrac{\text{1 mol}}{\text{18.02 g}} = \text{1.550 mol}\\\\n_{\text{N}_{2}} = \text{12.64 g} \times \dfrac{\text{1 mol}}{\text{14.01 g}} = \text{0.9022 mol}\\\\n_{\text{He}} = \text{5.54 g} \times \dfrac{\text{1 mol}}{\text{4.003 g}} = \text{1.384 mol}[/tex]
2. Calculate the total moles
[tex]n_{\text{tot}} = \text{(0.7969 + 1.550 + 0.9022 + 1.384) mol = 4.633 mol}[/tex]
3. Calculate the mole fraction of helium
[tex]\chi = \dfrac{n_\text{He}}{n_{\text{tot}}} = \dfrac{\text{1.384 mol}}{\text{4.633 mol}}= 0.2987[/tex]
4. Calculate the partial pressure of helium:
[tex]p_{\text{He}} = \chi_{\text{He}} p_{\text{tot}}= 0.2987 \times \text{12 atm} = \textbf{3.6 atm}\\\\p_{\text{He}} = \boxed{\textbf{3.6 atm}}[/tex]
Answer:
The partial pressure of He = 3.97 atm
Explanation:
Given:
Mass of CO2 = 35.07 g
Mass of H2O = 27.93 g
Mass of N2 = 12.64 g
Mass of He = 5.54 g
Total pressure P = 12 atm
To determine:
The partial pressure of He
Calculation:
Based on Dalton's law, the partial pressure of a gas can be expressed as a product of its mole fraction and the total pressure
[tex]P(gas)=X(gas)*P(total)-----(1)[/tex]
where X(gas) = mole fraction
[tex]X(gas)=\frac{moles(gas)}{moles(total)}----(2)[/tex]
[tex]Moles(CO2)=\frac{mass(CO2)}{mol.wt.(CO2)}=\frac{35.07g}{44g/mol}=0.7970[/tex]
[tex]Moles(H2O)=\frac{mass(H2O)}{mol.wt.(H2O)}=\frac{27.93g}{18g/mol}=1.552[/tex]
[tex]Moles(N2)=\frac{mass(N2)}{mol.wt.(N2)}=\frac{12.64g}{28g/mol}=0.4514[/tex]
[tex]Moles(He)=\frac{mass(He)}{at.wt.(He)}=\frac{5.54g}{4g/mol}=1.385[/tex]
Therefore:
Moles of He = 1.385
Total moles = 0.7970+1.552+0.4514+1.385 =4.188
Substituting the appropriate values in equation (1) gives:
[tex]P(He)=X(He)*P(total)[/tex]
[tex]P(He)=\frac{1.385}{4.188}*12 atm = 3.97 atm[/tex]
