Asample 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 841 mm hg and the temperature is now 26 °c. there are now mol of gas in the flask.

To solve this problem, we assume ideal gas so that we can use the formula:

PV = nRT

since the volume of the flask is constant and R is universal gas constant, so we can say:

n1 T1 / P1 = n2 T2 / P2

1.9 mol * (21 + 273 K) / 697 mm Hg = n2 * (26 + 273 K) / 841 mm Hg

n2 = 2.25 moles

The moles of gas after the addition of more gas have been 2.25 mol.

To calculate moles of the gas:

We assume ideal gas in order to utilize the formula,

The volume of the flask is constant, and

R is the universal gas constant,

According to the ideal gas,

PV = nRT

Since V and R are constant,

T1 = 21 = 294 K

n1 = 1.9 mol

P1 = 697 mm Hg

T2 = 26 = 299 K

P2 = 841 mm Hg

Substituting the values:

n2 = 2.25 mol.

The moles of gas after the addition of more gas have been 2.25 mol.

To learn more about ideal gas equation, refer to the link:

link

i do not get it   at all