You have to find the number of moles of hydrogen gas produced when zinc and hydrochloric acid reacted. To do this you need to use the equation PV=nRT and solve for n.(n=PV/RT) I would use 0.08206 atmL/molK For the gas constant so you need to convert 22°C into Kelvin, 748mmHg into atm, and 59.1mL into L. 22°C+273K=295K 748mmHgx(1atm/760mmHg)=0.984atm 59.1L=0.0591L plugging everything in: n=(0.0591Lx0.984atm)/(0.08206 atmL/molKx295K) n=0.00240mol H₂ After finding the amount of hydrogen gas, you can find the volume of gas at STP by divide it by the molar volume of gas (22.4mol/L). 0.00240mol/22.4mol/L=1.07L H₂ The answer is 1.07L of hydrogen gas at STP was released from the reaction. I hope this helps. Let me know if there was anything that was unclear to you.