This question is an application of Gay-Lussacs law which states that the pressure and temperature of a gas are positively related as such (p1/t1)=(p2/t2). For all gas law problems it is necessary to convert all temperature units to Kelvin which can be done using the following formula (K=C+273.15). After being converted the needed temperatures are 392.15 Kelvin for the initial pressure and 529.15 Kelvin for the unknown pressure. When plugged into the equations for Gay-Lussacs law the result is (1.56/392.15)=(p2/529.15) When this proportion is solved for p2 the final answer is 2.11atm. Please let me know if you need help with any of the mathematical steps individually.