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A student weighs an empty flask and stopper and finds the mass to be 55.4415 g.

ID: 1284570 • Letter: A

Question

A student weighs an empty flask and stopper and finds the mass to be 55.4415 g. She then adds about 5 mL of an unknown liquid and heats the flask in a boiling water bath at 100 degrees C. After all the liquid is vaporized, she removes the flask from the bath, stoppers it, and lets it i s cool. After it is cool, she momentarily removes the stopper, then replaces it and weighs the flask and condensed vapor, obtaining a mass of 56.0397 g. she dries the flask and fills with water , and weighs the flask and water and obtains a toatl weight of 271.241 grams. The barometric pressure in the laboratory 752 mm. Hg and the temperature is 19.5 degrees C is found to be 0.996532 g/ml.

a. What was the pressure of the vapor in the flask atm? P = ______ amt b. What was the temperature of the vapor in K? the volume of the flask in liters? T =______K, V=______ L c. What was the mass of vapor that was present in the flask? g = ___________grams d. How many moles of vapor are present? n =___________grams e. What is the mass of one mole of vapor? MM=___________g/mole

Explanation / Answer

flask = 55.4415g
5ml liquid at 100