Does anyone have any idea what this means lol

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