<li><p>Given that a sample of air is made up of nitrogen, oxygen, and argon in the mole fractions 78% N2, 21% O2, and 1.0% Ar, what is the density of air at standard temperature and pressure?</p></li>
<li><p>Helium is collected over water at 25degs C and 1.00 atm total pressure. What total volume of gas must be colected to obtain 0.586g of helium? (At 25degs C the vapor pressure of water is 23.8 torr.)</p></li>
<li><p>Write reactions to show how nitric acid and sufuric acids are produced in the atmosphere.</p></li>
</ol>
<p>Is this how you do #64?</p>
<p>0.78(molar mass of N2) + 0.21(molar mass of O2) + 0.01(molar mass of Ar) = molar mass of Air.
0.78(28.02) + 0.21(32) + 0.01(39.95) = 28.98g Air.</p>
<p>Molar Mass = dRT/P
d = ((Molar Mass) P)/RT
d = ((28.98g) Air)(1.00atm))/((0.08206)(273.15K)) = 1.3g/L</p>
<p>The density of air is 1.3 g/L.</p>
<hr>
<p>92.</p>
<p>0.586g He x (1mol He/.003g He) = 0.146mol He</p>
<p>PV = nRT
V = nRT/P
v = ((0.146mol He)(0.08206)(298.15K))/(1.00atm) = 3.57L He.</p>
<p>The volume of HE is 3.57L. Am I suppose to use 1.00 atom (assuming its at STP, or use 23.8torr given in the problem?)</p>
<p>64.</p>
<p>0.78(molar mass of N2) + 0.21(molar mass of O2) + 0.01(molar mass of Ar) = molar mass of Air.
0.78(28.02) + 0.21(32) + 0.01(39.95) = 28.98g Air.</p>
<p>Molar Mass = dRT/P
d = ((Molar Mass) P)/RT
d = ((28.98g) Air)(1.00atm))/((0.08206)(273.15K)) = 1.3g/L</p>
<p>The density of air is 1.3 g/L.</p>
<hr>
<p>92.</p>
<p>0.586g He x (1mol He/.003g He) = 0.146mol He</p>
<p>PV = nRT
V = nRT/P
v = ((0.146mol He)(0.08206)(298.15K))/(1.00atm) = 3.57L He.</p>
<p>The volume of HE is 3.57L. Am I suppose to use 1.00 atom (assuming its at STP, or use 23.8torr given in the problem?)</p>
<hr>
<p>93.</p>
<p>2NO2 (g) + H2O (l) ---> HNO3 (aq) + HNO2 (aq)
SO3 (g) + H20 (l) ---> H2SO4 (aq)</p>
<p>Are these right? I tried but I'm not really sure.</p>
<p>72.</p>
<p>0.586g He x (1mol He/4.003g He) = 0.146mol He
PV=nRT
V=nRT/P=(0.146mol He)(0.08206)(298.15K)/(23.8torr/760torr) = 114L He</p>
<p>For 93, look up the ostwald process and the contact process for more details</p>
<p>4NH3 + 5O2 --> 4NO + 6H2O
2NO + O2 --> 2NO2
NO2 + H2O --> HNO3</p>
<p>2SO2 + O2 --> 2SO3
SO3 + H2O --> H2SO4 (not suitable for industrial use)
Industry uses this step instead
SO3 + H2SO4 --> H2S2O7
H2S2O7 + H2O --> 2H2SO4</p>