37 End-of-Chapter Material
[latexpage]
Additional Exercises
- What is the pressure in pascals if a force of 4.88 kN is pressed against an area of 235 cm2?
- What is the pressure in pascals if a force of 3.44 × 104 MN is pressed against an area of 1.09 km2?
- What is the final temperature of a gas whose initial conditions are 667 mL, 822 torr, and 67°C, and whose final volume and pressure are 1.334 L and 2.98 atm, respectively? Assume the amount remains constant.
- What is the final pressure of a gas whose initial conditions are 1.407 L, 2.06 atm, and −67°C, and whose final volume and temperature are 608 mL and 449 K, respectively? Assume the amount remains constant.
- Propose a combined gas law that relates volume, pressure, and amount at constant temperature.
- Propose a combined gas law that relates amount, pressure, and temperature at constant volume.
- A sample of 6.022 ×1023 particles of gas has a volume of 22.4 L at 0°C and a pressure of 1.000 atm. Although it may seem silly to contemplate, what volume would one particle of gas occupy?
- One mole of liquid N2 has a volume of 34.65 mL at −196°C. At that temperature, 1 mol of N2 gas has a volume of 6.318 L if the pressure is 1.000 atm. What pressure is needed to compress the N2 gas to 34.65 mL?
- Use two values of R to determine the ratio between an atmosphere and a torr. Does the number make sense?
- Use two values of R to determine how many joules are in a litre-atmosphere.
- At an altitude of 40 km above the earth’s surface, the atmospheric pressure is 5.00 torr, and the surrounding temperature is −20°C. If a weather balloon is filled with 1.000 mol of He at 760 torr and 22°C, what is its:
- initial volume before ascent?
- final volume when it reaches 40 km in altitude? (Assume the pressure of the gas equals the surrounding pressure.)
- If a balloon is filled with 1.000 mol of He at 760 torr and 22°C, what is its:
- initial volume before ascent?
- final volume if it descends to the bottom of the Mariana Trench, where the surrounding temperature is 1.4°C and the pressure is 1,060 atm?
- Air — a mixture of mostly N2 and O2 — can be approximated as having a molar mass of 28.8 g/mol. What is the density of air at 1.00 atm and 22°C? (This is approximately sea level.)
- Air — a mixture of mostly N2 and O2 — can be approximated as having a molar mass of 28.8 g/mol. What is the density of air at 0.26 atm and −26°C? (This is approximately the atmospheric condition at the summit of Mount Everest.)
- On the surface of Venus, the atmospheric pressure is 91.8 atm, and the temperature is 460°C. What is the density of CO2 under these conditions? (The Venusian atmosphere is composed largely of CO2.)
- On the surface of Mars, the atmospheric pressure is 4.50 torr, and the temperature is −87°C. What is the density of CO2 under these conditions? (The Martian atmosphere, similar to its Venusian counterpart, is composed largely of CO2.)
- HNO3 reacts with iron metal according to Fe(s) + 2HNO3(aq) → Fe(NO3)2(aq) + H2(g). In a reaction vessel, 23.8 g of Fe are reacted but only 446 mL of H2 are collected over water at 25°C and a pressure of 733 torr. What is the percent yield of the reaction?
- NaHCO3 is decomposed by heat according to 2NaHCO3(s) → Na2CO3(s) + H2O(ℓ) + CO2(g). If you start with 100.0 g of NaHCO3 and collect 10.06 L of CO2 over water at 20°C and 0.977 atm, what is the percent yield of the decomposition reaction?
- Determine if the following actions will cause the pressure of a particular gas sample to increase, decrease, or remain the same:
- decreasing the temperature
- decreasing the molar mass of the gas
- decreasing the volume of the container
- Under what conditions do gases deviate most from ideal gas behaviour? Explain your answer.
- Place the following gases in order from lowest to highest average molecular speed at 25°C: He, Ar, O2, I2.
- The effusion rate of an unknown noble gas sample is 0.35 times that of neon, at the same temperature. Determine the molecular weight and identity of the unknown noble gas.
- Use the van der Waals equation to determine the pressure of 2.00 moles of helium in a 5.00 L balloon at 300.00 K. How does this value compare to what you would obtain with the ideal gas law?
Answers
- 208,000 Pa
- 1,874 K
- [latex]\dfrac{P_1V_1}{n_1}=\dfrac{P_2V_2}{n_2}[/latex]
- 3.72 × 10−23 L
- 1 atm = 760 torr
-
- 24.2 L
- 3155 L
- 1.19 g/L
- 67.2 g/L
- 3.99%
-
- decreased pressure
- increased pressure
- increased pressure
- I2 < Ar < O2 < He
- van der Waals: 9.94 atm, ideal: 9.85 atm