2. Convert these pressures to atm: 1 atm! Or to mm Hg, 760 mm Hg! 760 mm Hg! 1 atm. 800 mm Hg 380 mm Hg 0.75 atm 0.25 atm

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1 Chemistry L 3, Gas laws: Chapter 12: Name! Page 1 pg and Notes: Keep your Forces handout. We will not use kilopascals for pressure on worksheets or tests. Show your work on all worksheets!! Temperature and Pressure Conversions 1. Convert these Temperatures to Kelvin: K = C + 273! Or to Celsius C = K C 27 C 100 K 273 K 2. Convert these pressures to atm: 1 atm! Or to mm Hg, 760 mm Hg! 760 mm Hg! 1 atm 800 mm Hg 380 mm Hg 0.75 atm 0.25 atm Boyle's law : P1V1 = P2V2! (Temperature constant, p. 333) 3. A 200 ml sample of H 2 gas is collected at a pressure of 1.05 atm. If the temperature remains constant, what volume will the gas occupy at 600 mm Hg? (266 ml) 4. An average adult has a deep breath lung capacity of about 4.5 L L of air is measured at 740 mm Hg pressure. It is compressed until its volume is 3.50 L. What is its new pressure (assuming unchanged temperature)? (951 mm Hg) Gay-Lussac's Law :! P1 = P2! (Volume constant, T MUST be in Kelvin!!! p. 338) T1 T2! 5. Some CO 2 gas at 760 mm Hg pressure and 73.0 C in a sealed metal container is heated to 27.0 C. What is its new pressure? (1140 mm Hg) 6. The pressure in an automobile tire is 2.00 atm at 27.0 C. At the end of a road trip the pressure has risen to 2.20 atm. What is the temperature of the air in the tire, assuming the volume has not changed? Calculate the final T in Kelvin, then change to C. (330 K, 57 C)

2 Deriving the Volume and Temperature relationship: 7. A student measured the Volume and Temperature of a gas in a flexible container. The Pressure and amount of particles remained constant. Here is their data. Volume(mL) Temperature (K) Volume(mL) Temperature (K) a. Is the Volume vs. Temperature relationship Direct or Inverse? b. As the Temperature of a gas Increases, does the Volume increase or decrease? c. Would a graph of this data be Linear or a Hyperbola? d. Is V times T or V/T a constant? Calculate the constant, include units! (0.366 ml/k) e. Explain how Kinetic Theory explains this relationship. f. The Temp of this gas is changed until its volume is ml. Was the gas heated or cooled from the final state above (124.5 ml at 340 K)? Explain why you think so. g. Calculate the final Temperature of the gas in part f, and convert your answer to C. (400 K, 127 C) The Volume Temperature relationship! V1 = V2! (Pressure constant, T MUST is called Charles' law : T1 T2! be in Kelvin!!!! p ) 8. A balloon is placed in a freezer and has a Volume of 500 ml at 23.0 C. It is then removed from the freezer. What will be its volume at C (assuming constant pressure)? (600 ml) Problems from Combined gas law :! P1 V1 = P2 V2! (number of moles constant) (p ) T1! T2! (T... you should know by now) 9. The gas in a balloon occupies 100 ml at 27 C and 570 mm Hg. What will be its pressure if the volume is decreased to 50 ml and temperature to 48.0 C? (855 mm Hg) 10. The pressure of a 2.00 L sample of a gas is 3.50 atm, and its temperature is 127 C. The gas is heated until it has a new volume of 3.00 L and a new pressure of 5.25 atm. What is its new temperature, in C? (900 K, 627 C)

3 Chemistry Level 3 : Gas Laws! Name! Page 3 Ideal gas law problems : PV = nrt! P must be in atm V must be in Liters (p ) n is the number of moles of the gas Remember: STP = 0 C, 1 atm R = L atm /mol K T must be in K 1. What is the pressure of 30.0 moles of N 2 gas in a 55.0 L storage tank at 27.0 C? (13.4 atm) 2. What is the volume occupied by 4.00 grams of O 2 gas at STP? (change g >mol)(2.80 L) 3. a. A gas in a 500 ml storage tank has a pressure of 1520 mm Hg at 27.0 C. How many moles of a gas are in this tank? ( mol) b. If this gas is methane, CH 4, what is the mass of the CH 4 gas in the tank? (0.650 g) 4. a. A gas has a volume of 400 ml at 1 atm pressure and 27.0 C. How many moles of gas are in this sample? ( mol) b. This gas has a mass of 1.04 grams. Calculate the experimental formula weight of the gas. (64.0 g/mol) c. A test reveals the gas is made of Sulfur and Oxygen. Is this gas SO 2 or SO 3? Dalton's law of partial pressures: Ptotal = P1 + P2+ P3 +...! (can use mm Hg or atm) (p ) 5. On a Humid summer day the partial pressure of the N 2 in the air is atm, of O 2 = 160 mm Hg and of H 2 O vapor = 25 mm Hg. What is the total pressure? (780 mm Hg) 6. Underwater environments usually contain a lot of Helium gas because N 2 and O 2 gas are bad for us at high pressures. For example, O 2 gas is toxic if its Partial pressure is above about 1.4 atm. In an underwater environment, the Total pressure is 20.0 atm and the partial pressure of the He is mm Hg and of N 2 is 800 mm Hg. What is the Partial pressure of the O 2 in this environment? Is it safe? (700 mm Hg, 0.92 atm, yes)

4 Graham s Law:(p.352-3) Lighter gases move (diffuse, effuse) faster than heavier gases Page 4 Distance A moves = Formula Weight B = Rate A Gas A = Gas B = Lighter, Distance B moves Formula Weight A Rate B Heavier, Faster Slower 7. Which gas effuses faster, Chlorine (Cl 2 ) or Hydrogen (H 2 )? How much faster? (Hint: Find the Ratio Rate A/Rate B) (6 x) 8. In an experiment, N 2 gas diffuses 43.0 cm in the same time an unknown gas diffused 25.0 cm. What is the formula weight of the unknown gas? If it's a Noble gas, which gas is it? (82.8 g/mol) 9. During an experiment, O 2 gas traveled 30.0 cm in the same time an unknown gas traveled 41.0 cm. What is the formula weight of the unknown gas? Is it H 2 S, HF or NH 3? (17.1 g/mol) Real and Ideal gases 10. What would happen to the volume of a gas under the following conditions? (p ) (gets smaller, gets larger, stays the same, or can't tell) a. Increase Temp, keep pressure and amount constant b. Decrease pressure, keep temp and amount constant c. Increase pressure, add gas, temp constant d. Increase temp, decrease pressure, amount constant e. Add gas to a metal cylinder f. Double the Kelvin temp, double the pressure 11. Identify the following as characteristic of an Ideal Gas (I) or a Real Gas (R) (p ) a. Particles are very small b. Particles have no volume c. Will have 0 volume at 0 K d. Would be a solid at 0 K d. Have weak attractive forces e. Have no attractive forces f. Obey gas laws at high T, low P g. Obey gas laws at all T and P h. Would never become a liquid i. Will eventually become a liquid 12. Which real gas would act most like an Ideal gas? Why? SO 2 Rn HCl (polar) Ar 13. If a real gas has strong attractive forces, would its Volume at Low Temperature be more or less than an ideal gas? Why do you think so?

5 Chemistry Level 3 : Gas Laws Review! Name Page 5 1. In an experiment, you collect 6.00 L of butane gas at 27.0 C and 2.00 atm total pressure. The mass of the butane gas you collected is g. a. How many moles of gas are did you collect? b. Calculate your experimental formula weight of butane gas. (0.487 mol, 58.1 g/ mol) c. What is the Formula for butane: C 2 H 6 C 3 H 8 or C 4 H 10? d. Oops! The Pressure sensor is wrong, and it s reading too high (so the Actual Pressure is lower than 2.0 atm). Would this make your experimental moles of gas too high or too Low? Explain why you think so. e. The group across from you also collected g butane gas, 2.00 atm P, and 27.0 C. Oops! Their Temperature probe is wrong, and the actual Temp is Higher than 27.0 C. Is their experimental Volume of gas More, Less or the Same as 6.00 L? Explain why you think so. 2. A certain gas diffuses 50.0 cm in the same time O 2 gas diffuses 12.5 cm. What is the formula weight of the gas? What gas is it? (2.0 g/mol) 3. Consider the Pressure and Temperature relationship (Gay-Lussac s Law) a. Is it Direct or Inverse? b. Would a graph of this data be Linear or a Hyperbola? c. Is P times T or P/T constant? d. What unit do you need to use to express your Temperature for this relationship to hold? Why? e. Explain how Kinetic Theory explains this relationship. f. If there are no sources of error, what should be the Temperature at 0 pressure? Why?

6 ! Page ml of a gas has a pressure of 380 mm Hg at 73 C. What is its new pressure at 173 C if the volume increases to 200 ml? (95 mm Hg) 5. A metal gas cylinder (constant volume) at a temperature of 127 C contains a gas at 200 atm pressure. If the pressure is reduced to 100 atm, what is its new temperature in C? (200 K, 73 C) 6. The total pressure of N 2 and O 2 in an oxygen tent is 1.10 atm. If the partial pressure of the N 2 is 456 mm Hg, what is the partial pressure of the O 2 in the oxygen tent? (0.50 atm) 7. Which gas diffuses faster, He or F 2? How much faster? (3.1x) 8. Describe a practical application or example from everyday life of Boyle s Law (the Pressure and Volume relationship). 9. An 80.0 Liter helium tank has a pressure of 100 atm at 77.0 C. How many grams of Helium are in the tank? (1115 g) b. How many balloons can the helium in this tank fill? Assume the balloons measure 10.0 L at 1.00 atm pressure and 27.0 C. (686) 10. A balloon with a volume of 1.50 L at 27.0 C is cooled to 173 C. What is its new volume assuming the pressure stays constant? (0.50 L) 11. A hot air balloon has a volume of 100 L at 1.00 atm pressure. If the temperature stays constant, what is its new volume at 0.80 atm pressure? (125 L)