Gas Stoichiometry at STP You want to calculate the number of moles H2O that form from 13.5 L O2, assuming the reaction is at STP. Use the dimensional analysis below to set up the two-step calculation. Which ratio should be used for the first conversion, from liters O₂ to moles O₂? Ratio 2 Ratio 3 Ratio 1 Ratio 4
