States of Matter:

It’s A Gas

Century High School

Chemistry Instructors: Moertel, Stroh and Handlon

Name ______Hour____

General Chemistry Standards Unit 8 Gases and The States of Matter

  1. I can describe the states of matter in terms of motion of the molecules.
  1. I can use the kinetic molecular theory to explain how changes in energy content affect the state of matter (solid, liquid and gaseous phases).
  1. I can use the Kinetic Molecular Theory to explain the behavior of gases.
  1. I can use the Kinetic Molecular Theory to explain the relationships of gas properties such as pressure, temperature, volume and number of particles (moles).
  1. I can use the Combined Gas Law to calculate changes in volume, temperature or pressure of a gas given the initial volume, temperature or pressure of the gas including the volume at Standard Temperature and Pressure.

Unit 8 Review Questions:

  1. Compare the behavior of the molecules of a liquid and their behavior as a gas using the Kinetic Molecular Theory (explain the “motion” of the molecules of each state).

2.Describe the effect of temperature on the molecules in each state of matter (solid, liquid, gas):

  1. What happens when the temperature is increased?
  1. When the temperature is decreased?

3. Use the gas laws to solve the following problems: SHOW ALL WORK INCLUDING YOUR P1, V1, T1 AND P2, V2, T2.

  1. The pressure of air on a 4.6 L container is 1.18 atm. What is the new pressure if the sample is transferred to a 330 L container?
  1. A balloon has a volume of 5.3 L and is filled at a temperature of 65°C. What volume will the balloon occupy at a temperature of 42°C?
  1. The pressure of the oxygen gas inside a canister is 5.00 atm at 25°C. The canister is located at a camp high on Mount Everest. If the temperature falls to -10.0°C, what is the new pressure inside the canister?
  1. A gas at 110 kPa and 30.0°C fills a flexible container with an initial volume of 2.00 L. If the temperature is raised to 80.0°C and the pressure increases to 440 kPa, what is the new volume?
  1. A gas has a volume of 50.0 ml at 0.90 atm and 23.0°C. How much is the gas volume at STP?

Review Notes

Review what we already know!!!

Gas Laws

Boyle’s Law: P1V1 = P2V2

Charles’s Law:

Combined Gas Law

Standard Temperature and Pressure (STP) 1 atmosphere and 273 K

Units / Fill in the conversion table
Pressure (P) / Full Form / Short form / 1 atm / 1 torr / 1 mmHg / 1 kPa
Atmospheres / 1 atm
Torr / 760 torr
Milimeters of Mercury / 760 mmHg
Kilipascals / 101.3 kPa
Temperature (T) / Short Form / 1 K / 1°C
K = C + 273 / Kelvin
Celsius
Volume (V) / Short form / 1 L / 1 mL
Liters
Milliliters

Demonstrations of the Kinetic Molecular Theory

Part I KMNO4 and water (Immediate Observations)

Observations at end of class:

Predict what the system might look like tomorrow.

Observations after 24 hours:

What explains this behavior?

Part II: Demo: Copper and nitric acid

Immediate Observations:

Observations at end of class:

What explains this behavior?

Kinetic Molecular Theory: A Matter of State Video Notes

What are the 3 states of matter:

  1. ______
  2. ______
  3. ______

Can Crushing Demo

  • What happened to the water inside the can?
  • What happened to the steam inside the can when the heat was turned off?
  • Why did the cap need to be put on the can?
  • What force caused the can to crush?

Heated Metal Ball Demo

  • What substance is inside the metal ball?
  • What happens to pressure when the gas is heated? Why?
  • What happens to pressure when the gas is cooled? Why?

When gases are cooled enough, they change state to become ______

According to the ______, a ______consists of point-sized particles, with no ______whatsoever, that bounce off each other in perfectly ______collisions. The ______of a gas enclosed in a container results from the collisions of the particles with the walls of the container. If we increase the temperature of an ideal gas held in a container of constant volume, the pressure ______and always remains directly proportional to the ______. If we increase the pressure on a gas, the volume of the gas goes ______proportionately. If we decrease the pressure on a gas the volume of the gas goes ______proportionately.

Characterizing Types of Gases in the Lab

  1. Put about 20-30 drops of HCl in a test tube. Now add a very small scoop of sodium bicarbonate (NaHCO3). Record your observations.

Light wood splint and hold the burning end in the mouth of the test tube, but do not drop it into the test tube. Record your observations. Then repeat with a glowing splint.

When you are done rinse the contents of the test tube down the sink.

  1. Put about 2-3 ml of hydrochloric acid (HCl) in a test tube. Now get a piece of magnesium (Mg) ready and ignite a wooden splint. Drop the magnesium in the acid.

Hold the burning splint just inside the mouth of the test tube, but do not drop it into the test tube. Record your observations.

Repeat using a glowing splint.

  1. Place about 2-3 ml of hydrogen peroxide (H2O2) in a test tube. Then add a SMALL spatula tip of manganese dioxide catalyst to the hydrogen peroxide solution. After a couple of minutes, record what happens (it may take a couple minutes so don’t walk away). Then test the gas with a burning splint. Record all your observations.

Repeat with a glowing splint. Rinse out the test tube when done.

Analysis:

  1. Construct chemical equations for each of the reactions, then balance them and identify what type of reaction is taking place.
  2. Based on your observations, what type of gas was being formed in each experiment? Justify your answers.
  3. Name one possible use for each of the gases produced in your experiments.
  4. How to Determine What Type of Gas you Have (tests for gases)

Burning & Glowing Splint Test

Glowing splint in CO2 ______

Glowing splint in H2 ______

Glowing splint in O2 ______

Burning splint in CO2 ______

Burning splint in H2 ______

Burning splint in O2 ______

The Gas Laws Lab

Part I: Boyle’s Law Lab Pressure and Volume

Setup Steps:

  1. Turn on the Labquest device.
  2. Plug the pressure sensor adapter into the slot labeled CH 1.
  3. Using the stylus, tap SENSORS in the menu bar.
  4. Click on Sensor Set up
  5. Click the pull down menu from the CH 1 field.
  6. From the menu that appears, choose PRESSURE (you will have to scroll down).
  7. From the new menu that appears choose GAS PRESSURE.
  8. In the screen that appears, check to make sure the units are shown as kPa. If not, pull down the menu and choose kPa. Click OK.
  9. The syringe has a blue toggle mechanism that opens and closes the syringe to the pressure gauge. Make sure this is open. You can tell when it is open by pushing down the plunger and watching the pressure measurement on the display – it should change a lot as you move the plunger.

Once set up is complete, begin collecting data and record in this table:

Volume (mL) / Pressure (kPa)
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0

Analysis:

  1. Use your data to construct a graph on the graph paper below. Volume should be on the x-axis and pressure on the y-axis. Plot the points and then sketch the graph.
  1. What relationship do you see between pressure and volume? As pressure goes up then what happens to the volume? When volume goes down what happens to the pressure?

Pressure (KPa)

110
100
90
80
70
60
50
40
30
20
10

02468101214161820

Volume (mL)

Part II: Charles’s Law Lab Pressure and Temperature

Practice Boyle’s Law Gas Problems

Boyle’s Law: P1V1 = P2V2

  1. A gas occupies a volume of 3.86 L at 0.750 atm. At what pressure will the volume be 4.86 L
  1. A 4.50 L container of nitrogen gas at 28.0 0C is heated to 56.0 0C. Assuming the volume of thecontainer can vary, what is the new volume of the gas?
  1. A gas cylinder contains 40.0 L of gas at 45.0 0C and has a pressure of 650. torr. What will the pressure be if the temperature is changed to 100. 0C?
  1. 15.00 L of gas at 45.0 0C and 800. torr is heatedto 400.0C, and the pressure changed to 300. torr. What is the new volume?

Molympics: It’s a Gas!

  1. A gas at 600. mmHg is cooled from 27 oC to –173 oC. What is the new pressure?
  1. A gas occupies a volume of 3.86 L at 0.750 atm. At what pressure will the volume be 4.86 L
  1. A 4.50 L container of nitrogen gas at 28.0 0C is heated to 56.0 0C. Assuming the volume of thecontainer can vary, what is the new volume of the gas?
  1. A gas cylinder contains 40.0 L of gas at 45.0 0C and has a pressure of 650. torr. What will the pressure be if the temperature is changed to 100. 0C?
  1. 15.00 L of gas at 45.0 0C and 800. torr is heatedto 400.0C, and the pressure changed to 300. torr. What is the new volume?