A 7.50 liter sealed jar at 18 °c contains 0.125 moles of oxygen and 0.125 moles of nitrogen gas. what is the pressure in the container?

The ideal gas equation is;

PV = nRT; therefore making P the subject we get;

P = nRT/V

The total number of moles is 0.125 + 0.125 = 0.250 moles

Temperature in kelvin = 273.15 + 18 = 291.15 K

PV = nRT

P = (0.250 * 0.0821) * 291.15 K : (7.50 L) = 0.796 atm

Thus, the pressure in the container will be 0.796 atm