Homework

**WebLecture**: *The Ideal Gas Law*

**Kotz and Triechel**, *Chemistry and Chemical Reactivity* Chapter 10: 1-3

*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.

1 Pa = 1 newton/meter^{2}

1 atm = 760 mmHg = 101.325 kPa

Boyle's Law: PV = C

Charles's Law: V = CT

Avogadro's Law: V = nC

Combind gas law: P_{1}V_{1}/T_{1} = P_{2}V_{2}/T_{2}

Ideal Gas Law: PV = nRT

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

**Homework problems**: See your Moodle assignment!

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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