AP Chemistry Notes

Chapter 5: Gasses

5.1 Pressure

• Pressure is defined by force/area• P=F/A• Standard pressure = pressure at sea level• Units for pressure at standard pressure• 1 Atm = 760 torr =760 mmHg = 101.325kPa =

101,325 Pa– These equivalents are given to you on the AP Exam

• Temperature and volume effect pressure

5.1 Example, Conversion between units of pressures

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5.2 The Gas Laws of Boyle and Charles

• Boyle’s Law – Used when temperature does NOT change– P (pressure) is inversely proportional to V (volume)– P1V1 = P2V2

• Charles Law– Used when pressure does NOT change– (P) Pressure is proportional to (T) temperature – V1/T1= V2/T2– Temperature HAS to be measures in Kelvin

5.2 example, using Charles/Bolyes Law

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5.3 The Ideal Gas Law

• We know that when measuring pressure temperature and volume won’t always stay so then we use the ideal gas law.

• PV=nRT where R is a constant of – R = 0.08206 L · atm/mol · K

5.3 example, using the Ideal Gas Law

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5.3 example, using the Ideal Gas Law in variable changes

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5.4 Gas Stoichiometry

• Simply put 1 mole of any gas is 22.42L– Given to you on AP exam

5.4 example, Gas stoichiometry

• I have 1 mole of a gas at 273K and 1 atm, what volume of gas do I have?

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5.4 example, Gas stoichiometry

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5.5 Dalton’s Law of Partial Pressures

• Often there a lot of different gasses in a container– thus we must use Dalton’s Law of Partial Pressures

to calculate how much of each gas there it

• Ptotal = P1+P2+P3

– Each number is a different gas in that container• Use one of the gas laws to calculate each

pressure

5.5 example, Using Dalton’s Law of Partial Pressures

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5.5 example, Using Dalton’s Law of Partial Pressures

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Learn! Multiple Choice Questions Based on these

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