The pressure in a container at 30 degrees celsius was 2.3 atm and had a volume of 2.2L, whatwould the volume be if the conditions were changed to STP

For a fixed mass of gas we can use the combined gas law.

(P1V1) / T1 = (P2V2) / T2

where P1 is pressure, T1 is temperature and V1 is volume at the first instance

and P2 is standard pressure and T2 is standard temperature and V2 is the volume at STP conditions

temperatures at both instances should be in kelvin scale

T1 - 30 °C + 273.15 = 303.15 K

T2 - 273.15 K

substituting the values in the equation

(2.3 atm x 2.2 L) / 303.15 K = (1.0 atm x V2) / 273.15 K

V2 = 4.6 L

the volume at STP is 4.6 L