A 1.20-g sample of an unknown gas is placed in a 275.0 mL flask at 35 0C and 1.00 atm. What is the molar mass of this substance ?

The density of a noble gas is 10.31 g/L at 3.0 atm and 25.0 ⁰C . Identify the gas.

A 3.55 g sample of an unknown gas at 33 degrees Celcius and 1.10 atm is stored in a 2.55 L flask. What is the density and molar mass of the gas?

12. Calculate the molar mass of a gaseous substance if 0.158 g of the gas occupies 31.7 mL at STP.

A gas occupies 30.0 L at 2.0 atm and 27 Celsius. How many moles of gas are present in the sample ?

At 25.0° C, a 10.00 L vessel is filled with 5.16 atm of Gas A and 7.89 atm of Gas B. What is the mole fraction of Gas B?

A 1.897 gram sample of an unknown gas is found to occupy a volume of 0.745 L at a pressure of 1.22 atm and a temperature of 32.5°C. What is the molecular weight of the unknown gas?

A sample of 0.400 L Ne initially at 1.181 atm and 240.ºC and a 0.150 L sample of O2 initially at 0.846 atm and 130.ºC are added to 500. mL flask held at 25.0ºC.  Which choice is closest to the total pressure in the flask? Enter your answer to three significant figures in units of atm.

2.2 L of He gas at 7.6 atm pressure and 25oC and 3.8L of Ne gas at 4.2 atm pressure and 25oC are combined at constant temperature into a 9.0 L flask.  What is the total pressure (in atm) in the 9.0 L flask?

A mixture of oxygen and krypton gases, in a 7.91 L flask at 41 °C, contains 8.74 grams of oxygen and 7.22 grams of krypton. The partial pressure of krypton in the flask is atm and the total pressure in the flask is atm.