A sample of gas (1.9 mol)is in a flask at 21°C and 697 mm Hg. The flask is opened and more gas is added to the flask. The new pressure is 782 mm Hg and the temperature is now 26°C. There are now __________ mol of gas in the flask.
A)1.6
B)2.1
C)2.9
D)3.5
E)0.28

Question

Quizplus · Accepted Answer

Using the combined gas law, we can solve for the number of moles of gas in the flask after the addition of more gas:P1V1/T1 = P2V2/T2(697 mmHg)(1.9 mol)/(21°C + 273.15) = (782 mmHg)(V2)/(26°C + 273.15)Solving for V2, we get:V2 = (697 mmHg)(1.9 mol)(26°C + 273.15) / (782 mmHg)(21°C + 273.15) = 2.1 molTherefore, there are now 2.1 mol of gas in the flask.

A Sample of Gas (1