COMBINED AND IDEAL GAS LAWS. COMBINED GAS LAW Do variables remain constant for gases??? ...
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Transcript of COMBINED AND IDEAL GAS LAWS. COMBINED GAS LAW Do variables remain constant for gases??? ...
COMBINED AND IDEAL GAS LAWS
COMBINED GAS LAW
Do variables remain constant for gases???
Temperature, pressure, and volume are CONSTANTLY changing for a gas based on the conditionsGas amount (n) is constant
COMBINED GAS LAW (CONT.)
Combination of all three laws into one equation (Boyle’s, Charle’s, and Gay-Lussac’s Laws)
Describes the relationship between pressure, volume, and temperature
Focus on initial and final conditions
COMBINED GAS LAW
•P1V1 = P2V2
T1 T2
Temperature—Kelvin
EXAMPLE 1:
A gas has a volume of 80.0ml at 27°C and 0.200 atm. What volume will the gas have at standard conditions?
EXAMPLE 2:
• A gas has a volume of 60.0ml at standard conditions. This volume is reduced to 10.0ml at 25.0°C. What is the necessary pressure for this volume reduction?
IDEAL GAS LAW
• Describes the general relationship among the variables: • Temperature• Pressure• Volume• Number of moles of gas
• Enables us to determine the value of a variable if the other three variables are known
IDEAL GAS LAW (CONT.)
•PV = nRT• P = pressure (atmospheres)• V = volume (liters)• T = temperature (Kelvin) • n = moles of the gas • R = 0.08206 Latm/molK (ideal gas constant)
EXAMPLE 1:
Many gases are available for use in the laboratory among compressed gas cylinders stored at high pressures. Calculate the mass of O2 (in grams) that could be stored at 21°C and 170atm in a cylinder with a volume of 60.0L.
EXAMPLE 2:
• Calculate the molecular weight of butane if 0.5813g of the gas fills a 250.0ml flask at a temperature of 24.4°C and a pressure of 742.6 mmHg.
EXAMPLE 3:
Calculate the density in grams per liter of O2 gas at 0°C and 1.00 atm.
EXAMPLE 4:
• A tank of hydrogen gas has a volume of 22.9L and holds 14.0 mol of gas at 12°C. What is the reading on the pressure gauge in atmospheres?
HOMEWORK
• Finish Gas Study Chart