Chemistry Chegg Worksheet
NI 2
ENGR 1540 Worksheet 22 Chapter 5
1. Pure gaseous nitrogen dioxide (NO2) cannot be obtained, because NO2 dimerizes, or combines with itself, to produce a mixture of NO2 and N2O4. A particular mixture of NO2 and N2O4 has a density of 2.39 g/L at 50℃ and 745 torr. What is the partial pressure of NO2 in this mixture?
2. One of the noble gases (Group 18 in the periodic table) has a density of 1.783 g/L at 0℃ and 1 atm. Which noble gas is this?
3. A mixture of CH4(g) and C3H8(g) with a total pressure of 425 torr is prepared in a reaction vessel. Just enough O2(g) is added to allow complete combustion of the two hydrocarbons. The gas mixture is ignited, and the resulting mixture of CO2(g) and H2O(g) is cooled back to the original temperature. If the total pressure of the products is 2.38 atm, what was the mole fraction of C3H8 in the original mixture?
4. A mixture of helium and neon gases has a density of 0.285 g/L at 31.0℃ and 374 torr. Find the mole fraction of neon in this mixture.
5. Table 5.1 provides the mole percentage composition of dry air. What is the mass percentage composition of dry air?
6. Use the composition of dry air from Table 5.1 to calculate the average density of dry air at 25℃ and 1 atm pressure.
7. Consider a room that is 14 ft×20 ft with an 8-ft ceiling.
a. How many molecules of air are present in this room at 20℃ and 750 torr?
b. If a pollutant is present at 2.3 ppm, how many pollutant molecules are in this room?
8. Nitric acid can be prepared by bubbling dinitrogen pentoxide into water. N2O5(g)+H2O(l)→2H+(aq)+2NO3-(aq)
a. How many moles of H+ are obtained when 1.50 L of N2O5 at 25℃ and 1.00 atm pressure is bubbled into water?
b. The solution obtained in (a) after reaction is complete has a volume of 437 mL. What is the molarity of the nitric acid obtained?
9. A 0.0125-g sample of a gas with an empirical formula of CHF2 is placed in a 165-mL flask. It has a pressure of 13.7 mm Hg at 22.5℃. What is the molecular formula of the compound?