In this experiment, a flask is filled with vapor( fastened by a piece of aluminum foil over the opening), by boiling a volatile unknown liquid in the flask. As it boils away, the vapor of the unknown pushes the aire out of the flask through a tiny pinhole opening, and eventually the flask is filled witha an atmosphere composed exlcusively of the unknown. The P, V, and T of the vapor will be determined and number of moles will be c alculated. When the flask is allowed to cool the vapor condenses and aire again refulls the flask. Re weighing the flask and figure out the the wight of the unknown vapor which filled the flask during the boiling.
REPORT SHEET Experiment 5 Molar mass of a condensable Vapor Unknown Number 1. Mass of flsk, foil cap, and rubber band 2. Mass of flask, foil cap, rubber band, and residual liquidae (after cooling) 3. Pressure of the vapor, mm Hg 4. Temperature of the vapor, C 5. Volume of vapor, ml. (same as flask) Caloalated quantities 6. Mass of vapor that filled the flask 7. Pressure of vapor, atm 8 Volume of vapor, L 9. Temperature of Vapor,K 10. Number of moles of vapor. mol 11. Molar Mass of vapor Show calculatioes for conversion of pressure and temperature and calculations of moles Post Lab Questions 1. Is the error in volume reading or the eror in mass reading greater in this experiment? Explain. (Hint! Consider uncertainties in the measurement tools) 2. If a drop of water clings to the outside of the foil cap and is not removed, how would the experimentally determined molar mass be affected? (Too high or too low) Explain 3. Briefly explain why it is not necessary to know the weight of the unknown liquid placed in the flask in step 2 of the procedure
