Question

Given a volume of 47.8 mL of gas at STP, _______________ moles of O2 exist

Answer 1

At STP, a mole of any gas occupies 22.4 L. So given 48.7 mL—or 0.0487 L—of O2 gas at STP, the number of moles of O2 that exist is 0.00217 moles.