Download - CHM 101/102 Laboratory Manual Molecular Weight Determination of Butane Gas General Chemistry 101/102 Laboratory Manual University of North Carolina at.

CHM 101/102CHM 101/102

Laboratory ManualLaboratory ManualLaboratory Manual

Molecular Weight Determination Molecular Weight Determination of Butane Gasof Butane Gas

General Chemistry 101/102General Chemistry 101/102Laboratory ManualLaboratory Manual

University of North Carolina at WilmingtonUniversity of North Carolina at Wilmington

CHM 101/102CHM 101/102


MW Determination of Butane GasMW Determination of Butane Gas

• PurposePurpose Determine the molecular weight (molar mass) of a Determine the molecular weight (molar mass) of a

gas from information about its mass, volume, gas from information about its mass, volume, temperature, and pressure.temperature, and pressure.

Demonstrate applications of the Ideal Gas Law Demonstrate applications of the Ideal Gas Law and Dalton’s Law of Partial Pressures.and Dalton’s Law of Partial Pressures.

• Safety ConsiderationsSafety Considerations Butane gas is very flammable. There should be Butane gas is very flammable. There should be

nono open flames in the laboratory during this open flames in the laboratory during this experiment.experiment.

CHM 101/102CHM 101/102


• ProcedureProcedure Fill a baby bottle with water to the very top.Fill a baby bottle with water to the very top. Cover the bottle with a glass plate.Cover the bottle with a glass plate. Invert the bottle in a pneumatic trough and Invert the bottle in a pneumatic trough and

carefully remove the glass plate.carefully remove the glass plate.


CHM 101/102CHM 101/102



• ProcedureProcedure Insert the tube from the butane canister under the Insert the tube from the butane canister under the

lip of the inverted baby bottle.lip of the inverted baby bottle. Release approximately 200 mL of gas into the Release approximately 200 mL of gas into the

bottle by pressing straight down on the valve. Do bottle by pressing straight down on the valve. Do not displace all of the water from the bottle.not displace all of the water from the bottle.

Push straight downPush straight down

CHM 101/102CHM 101/102



• ProcedureProcedure Raise and/or lower the baby bottle until the water Raise and/or lower the baby bottle until the water

level in the bottle is even with the water level in the level in the bottle is even with the water level in the trough, then read the volume of the gas from the trough, then read the volume of the gas from the graduations on the bottle.graduations on the bottle.

Water level in bottle lined up with water level in trough

CHM 101/102CHM 101/102



• Formulas and EquationsFormulas and Equations

M = g R TP V

P = butane

P - Pwatertotal