[1pt] The barometric pressure measured outside an airplaneat 8 km (26248 ft) was 348 mmHg
1. [1pt] The barometric pressure measured outside an airplane at 8 km (26248 ft) was 348 mmHg. Calculate the pressure in kPa. Do not enter unit.
2. [1pt] If 637 dm3 of krypton at 218 kPa and 18C is compressed into a 28.0-dm3 tank at the same temperature, what is the pressure (in kPa) of krypton in the tank? Enter unit.
3. [1pt] A sample of 70.0 cm3 of argon gas at 19C was contained at a pressure of 198 kPa in a J-shaped tube with mercury. Later the temperature changed. When the mercury level was adjusted to give the same pressure of argon, the gas volume changed to 45.3 cm3. What was the nal temperature of the argon? Give answer in C. Do not enter unit.
4. [1pt] Methanol can be produced in industrial plants by reacting carbon dioxide with hydrogen in the presence of a catalyst. Water is the other product. How many volumes of hydrogen are required for each volume of carbon dioxide when each gas is at the same temperature and pressure? Just enter the number.
5. [1pt] In an experiment, you ll a heavy-walled 3.00-L ask with methane gas, CH4. If the ask contains 3.47 g of methane at 28C, what is the gas pressure in atm? Enter unit.
6. [1pt] A 4.00-L ask was used to collect a 5.44-g sample of propane gas, C3H8. After the sample was collected, the gas pressure was found to be 718 mmHg. What was the temperature of the propane in the ask? Give answer in C. Do not enter unit.
7. [1pt] Calculate the density of hydrogen sul de gas, H2S at 34C and 893 mmHg. Obtain the density in grams per liter. Do not enter unit.
8. [1pt] You vaporize a liquid substance at 100C and 734 mmHg. The volume of 0.553 g of vapor is 224 mL. What is the molecular weight of the substance? Give answer in amu. Do not enter unit.
9. [1pt] Magnesium burns in air to produce magnesium oxide, MgO, and magnesium nitride, Mg3N2. Magnesium nitride reacts with water to give ammonia. Mg3N2(s) + 6H2O(l) ! 3Mg(OH)2(s) + 2NH3(g) What volume (in L) of ammonia gas at 25C and 746 mmHg will be produced from 4.64 g of magnesium nitride? Enter unit.
10. [1pt] Sodium hydrogen carbonate is also known as baking soda. When this compound is heated, it decomposes to sodium carbonate, carbon dioxide, and water. Write the balanced equation for this reaction.
11. [1pt] What volume (in liters) of carbon dioxide gas at 72C and 743 mmHg will be produced from 25.7 g of sodium hydrogen carbonate? Do not enter unit.
12. [1pt] The atmosphere in a sealed diving bell contained oxygen and helium. If the gas mixture has 0.300 atm of oxygen and a total pressure of 3.00 atm, calculate the mass of helium (in g) in 10.0 L of the gas mixture at 23C. Enter unit.
13. [1pt] An aqueous solution of ammonium nitrite, NH4NO2, decomposes when heated to give o nitrogen, N2. NH4NO2(s) ! 2H2O(g) + N2(g) This reaction may be used to prepare pure nitrogen. How many grams of ammonium nitrite must have reacted if 3.53 dm3 of nitrogen gas was collected over water at 24C and 96.7 kPa? Do not enter unit.
14. [1pt] A steel bottle contains 12.7 L of a gas at 11.2 atm and 22C. What is the volume (in L) of gas at STP? Enter unit.
15. [1pt] The combustion method used to analyze for carbon and hydrogen can be adapted to give percentage N by collecting the nitrogen from combustion of the compound as N2. A sample of a compound weighing 8.78 mg gave 1.81 mL N2 at 27C and 746 mmHg. What is the percentage N in the compound? Do not enter unit.
16. [1pt] Raoul Pictet, the Swiss physicist who rst lique ed oxygen, attempted to liquefy hydrogen. He heated potassium formate, KCHO2, with KOH in a closed 2.50-L vessel. KCHO2(s) + KOH(s) ! K2CO3(s) + H2(g) If 49.0 g of potassium formate reacts in a 2.50-L vessel, which was initially evacuated, what pressure (in atm) of hydrogen will be attained when the temperature is nally cooled to 20C? Use the preceding chemical equation and ignore the volume of solid product. Enter unit.
17. [1pt] A 48.90-mL sample of a 0.2040 M acid reacts with an excess of Na2CO3 to form 125.0 mL CO2 at 722 mmHg and 17C. If the acid is either HCl or H2SO4, which is it? Do not use subscript.
18. [1pt] A sample of zinc metal was reacted with an excess of hydrochloric acid. Zn(s) + 2HCl(aq) ! ZnCl2(aq) + H2(g) All of the zinc reacted, and the hydrogen gas was collected over water at 16C; the barometric pressure was 755 mmHg. The apparatus was similar to that shown in Figure 5.20, but the level of water inside the tube was 33.0 cm above the level outside the tube. If the volume of gas in the tube is 21.2 mL, how many grams of zinc were there in the sample? Do not enter unit. The density of Hg is 13.596 g/mL and the density of water is 1.000 g/mL.
19. [1pt] A mixture contained zinc sul de, ZnS, and lead sul de, PbS. A sample of the mixture weighing 6.11 g was reacted with an excess of hydrochloric acid. The reactions are ZnS(s) + 2HCl(aq) ! ZnCl2(aq) + H2S(g) PbS(s) + 2HCl(aq) ! PbCl2(aq) + H2S(g) If the sample reacted completely and produced 1.044 L of hydrogen sul de, H2S, at 22C and 741 mmHg, what were the percentages of ZnS and PbS in the mixture. Enter the percentage for ZnS rst, then PbS. Do not enter units.
20. [1pt] A mixture of Ne and Ar gases at 349 K contains twice as many moles of Ne as of Ar and has a total mass of 50.0 g. If the density of the mixture is 3.86 g/L, what is the partial pressure (in atm) of Ne? Enter unit.