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**Textbook assignment**: Read Kotz and Triechel, *Chemistry and Chemical Reactivity* Chapter 10: Sections 1 to 3

*10.1:*We know how to measure volume in standard metric units of distance (meters to liters), and we've already used temperature units (%deg;C, Kelvin). Now we look at units used to measure pressure: 1 atm (atmosphere) = 760 mmHg = 1.013 * 10^{5}P (Pascal) = 101.3 kPa (kilo Pascal) = 1.013 bar.*10.2:*Over several centuries, different philosophers recognized certain relationships between pressure, volume, temperature, and the amount of gas in a sample:**Boyle's Law:**Pressure * Volume = Constant**Charles's Law:**Volume = Constant * Temperature**Avogadro's Law:**Volume = number of molecules * Constant

*10.3:*We can combine the three laws we know now into a single law:**PV = nRT**. Since a mole of any gas has a molar mass M, a sample of n molecules has a mass m = nM, or n = m/M. We also know that density = mass/volume, so we can rewrite the gas law in terms of molar mass and mass: PV = (m/M) RT, and P(m/d) = nRT = P(m/d) = (m/M) RT so d = MP/RT. These relationships allow us to determine molar mass M for a substance.

Concept | Formula | Notes |
---|---|---|

Pascal Unit | 1 Pa = 1 newton/meter^{2} | |

Atmosphere Unit | 1 atm = 760 mmHg = 101.325 kPa | |

Boyle's Law | $$\mathrm{PV}\text{}=c$$ |
P: Pressure
V: Volume T: Temperature c: constant of proportionality |

Charles's Law | $$V\text{}=\text{}\mathrm{cT}$$ | |

Avogadro's Law | $$V\text{}=\text{}\mathrm{nc}$$ | |

Combined gas law | $$\frac{{P}_{1}{V}_{1}}{{T}_{1}}\text{}=\text{}\frac{{P}_{2}{V}_{2}}{{T}_{2}}$$ | |

Ideal Gas Law | $$\mathrm{PV}\text{}=\text{}\mathrm{nRT}$$ | R: Gas constant |

**Read the following weblecture before chat**: *The Ideal Gas Law*

Review the Videos at Thinkwell Video Lessons.

- Under "Gases: Gases and Gas Laws"
- Properties of Gas laws
- Boyle's Law
- Charles's Law
- The Combined Gas Law
- Avogadro's Law

Use the simulation below to explore the ideal gas law. In the Ideal Gas Law window, observe what happens to each characteristic as you

- Add heavy or light particles (or a mix).
- Use the pump to increase pressure.
- Open the top of the chamber to release particles and decrease pressure.
- Use the bucket at the bottom to heat or cool the chamber.

**Essay question**: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer**before**chat starts for this session.**Mastery Exercise**: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.

- There is no chapter quiz YET.

Devise a way to determine how the volume of a gas changes when pressure or temperature changes, while holding other factors (including amount of gas) constant. You will use your data to predict pressure outcomes with both volume and temperature change, and determine pressure and volume as temperature approaches absolute zero. Your procedure should include both data collection, analysis for prediction, and test runs to see if your predictions are accurate.

References:

- IGHCE Lab 14.1 OR HSCKM VIII-1: Volume-Pressure relationships (Boyle's Law)
- IGHCE Lab 14.2 OR HSCKM VIII-2: Volume-Temperature relationships (Charles' Law)
- IGHCE Lab 14.3 Pressure-Temperature relationship (Gay-Lussac's Law)
- Alternate Labs (two): Gas Volumes and Gas Generation

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