Temp in Kelvin = (Temp in O C) Temp in o C = (Temp in Kelvin) Perform the following conversions:

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1 Study: *Questions About Gases WS and More Questions About Gases WS *Go back over your notes taken from the book and in class. *Use your book: Chapter 3 PG The Kelvin temperature of a gas (or any substance) is directly proportional to the kinetic energy of the particles. The following equations show the relationship between Kelvin temperature and Celsius temperature: Temp in Kelvin = (Temp in O C) Temp in o C = (Temp in Kelvin) Perform the following conversions: o C to K o C to K K to o C 5. 77K to o C K to o C o C to K The pressure of a gas can be expressed in many different units depending on what it is being used for. For instance, pressure in tires is expressed in pounds per square inch (lb/in 2 ), or psi. Pressure on the weather channel is given in mmhg (millimeters of mercury) or inhg (inches of mercury). Each of the following units is equivalent to each other. Using these values to perform the following conversions: (show your work, multiply by a conversion factor, and cancel units) 1 atm = 14.7 psi = 760 mmhg = kpa = 760 torr Example: 69.3 psi = mmhg 69.3 psi 760 mm Hg = mmhg 14.7psi atm = mm Hg kpa = torr Torr = kpa kpa = atm psi = atm mm Hg = kpa kpa = mm Hg kPa = mm Hg atm = kpa

2 SHOW ALL WORK AND UNITS! Recall: P 1 x V 1 = P 2 x V 2 1. Given: P 1 = 1.8 atm P 2 = 2.6 atm V 1 = 145 ml V 2 =? First, predict will the volume will increase, decrease, or stay the same? Then solve. 2. A gas has a pressure of 4.80 atm and a volume of 3.0 L. What will the volume do if the pressure is changed to 2.40 atm? Circle your choice: increase, decrease, stay the same Calculate the new volume. 3. A bicycle pump has liters of air in it with a pressure of 15.4 psi What will the pressure be when the volume is reduced to L? 4. A weather balloon has a pressure of 2.8 atm and a volume of 455 L when it is at sea level. When the balloon rises to a height of about 10 miles, the volume of the balloon becomes L. What is the pressure in the balloon at this height? 5. A gas has a pressure of 454 mmhg and a volume of 1.3 L. What is the new volume if the pressure changes to 676mmHg? Match the variables used to describe gases to the correct unit. kpa atmospheres (atm) a. pressure o C L b. temperature ml o F c. volume K mm Hg

3 Recall: V 1 T 2 = V 2 T 1 1. The temperature inside my refrigerator is about 277 Kelvin. If I place a balloon in my fridge that initially has a temperature of 295K and a volume of 0.5 liters, what will be the volume of the balloon when it is fully cooled by my refrigerator? 2. Suppose you buy Ms. Gallaher some inflated balloons for Teacher Appreciation Day that are at room temperature. Explain what will happen to the balloons if you take them outside on a very cold day? 3. A hot air balloon starts with a beginning volume of liters, and a beginning temperature of 273K. It is then heated, and has a final temperature of 488K. What is its final volume, in liters? 4. A man heats a balloon in the oven. If the balloon initially has a volume of 0.4 liters and a temperature of 20 0 C, what will the volume of the balloon be after he heats it to a temperature of C? Don t forget to change the temperature to Kelvin. o C Some students believe that teachers are full of hot air. If I inhale 2.2 L of gas at a temperature of 18 0 C and it heats to a temperature of 38 0 C in my lungs, what is the new volume of the gas? Don t forget to change the temperature to Kelvin. o C + 273

4 Recall: P 1 T 2 =P 2 T 1 Don t forget to change the temperature to Kelvin. o C A mylar balloon is filled with helium gas to a pressure of 107kPa when the temperature is 22.0 C. If the temperature changes to 45.0 C, what will be the pressure of the helium in the balloon? 2. Determine the pressure change when a constant volume of gas at 1.00 atm is heated from 20. C to 30.0 C. 3. If a gas in a closed container is pressurized from 15.0 atmospheres to 16.0 atmospheres and its original temperature was 25.0 C, what would the final temperature of the gas be? 4. The temperature of a sample of gas in a steel container at 30.0 kpa is increased from C to C. What is the final pressure inside the tank? 5. A sample of gas at 3000 mm Hg inside a steel tank is cooled from C to 0.00 C. What is the final pressure of the gas in the steel tank?

5 Recall: P 1 V 1 T 2 =P 2 V 2 T 1 1. Seaweed plants release oxygen gas during photosynthesis. A ml bubble is released under water at 176 kpa and 283K. What will the bubble's volume be at the surface where the temperature is 288K and the pressure is kpa? a. Which gas law should be used to solve this problem? b. Now solve the problem 2. A sample of hydrogen gas has a volume of 65.0mL at a pressure of 0.992atm and a temperature of 16.0 C. What volume will the hydrogen occupy at 0.984atm and 25.0 C? Don t forget to change the temperature to Kelvin. o C A student collects 450.mL of HCl(g) at a pressure of 100.kPa and a temperature of 17.0 C. What is the volume of the HCl(g) at zero degrees Celsius and 101.3kPa? Don t forget to change the temperature to Kelvin. o C A small research submarine with a volume of 120,000 L has an internal pressure of 1.0 atm and an internal temperature of 15 0 C. If the submarine descends to a depth where the pressure is 150 atm and the temperature is 3 0 C, what will the volume of the gas inside be if the hull of the submarine breaks? 5. A gas balloon has a volume of liters when the temperature is 45.0 C and the pressure is mm of mercury. What will its volume be at 20.0 C and mm of mercury pressure?

6 States of Matter Use your textbook and the compare/contrast assignment that you already completed to fill in the following table. Shape Gas Liquid Solid Volume Proximity of particles Average Kinetic Energy Molecular Representation of a GAS LIQUID SOLID Energy removed Energy added

7 Directions: Fill in the blank with the appropriate phase change word. 1. A Popsicle changes from a solid to a liquid on a hot summer day. 2. Water in a tray changes to a solid when put in the freezer. 3. Dry ice changes from a solid to a gas. 4. A puddle changes from liquid to gas on a warm spring day. 5. A pot of liquid water is placed on a hot stove and begins to bubble. 6. Water droplets form on a bathroom mirror while you take a hot shower. 7. Water droplets on the mirror disappear after the fan is turned on. 8. M&Ms turn to a liquid when left in a warm car. 9. Is melting an endothermic or exothermic change? Explain. 3 During which part or parts of the graph is potential energy changing? 1 2 During which part or parts of the graph is kinetic energy changing? During which part or parts of the graph is a phase change occurring?

8 B F G D E A C 6. What is the temperature at point A? 0 C 7. What is the temperature at point B? 0 C 8. Describe what is taking place at point C. 9. Describe what is taking place at point D. 10. Describe what is taking place at point E. 11. Describe what is taking place at point F. 12. During which part or parts of the graph is the shape of the water, whether solid, liquid, or gas, changing, but the temperature is not changing? 13. During which part or parts of the graph are we heating water, in any shape, and increasing its temperature? 14. During which part of the graph could we have very dangerous, extremely hot steam, at temperatures of C, C, or even higher?

9 1. What is the normal freezing point of this substance? 2. What is the normal boiling point of this substance? 3. What is the triple point of this substance?, 4. f I had a quantity of this substance at a pressure of 1.25atm and a temperature of C and lowered the pressure to 0.25 atm, what phase transition(s) would occur? 5. At what temperature can the substance exist only as a gas? 6. If I had a quantity of this substance at a pressure of 0.75 atm and a temperature of C, what phase change(s) would occur if I increased the temperature to C? At what temperature(s) would they occur?