Baking soda and vinegar are mixed to form carbon dioxide gas according to the reaction below; the gas is collected at 21oC in an inverted graduated cylinder over water.
NaHCO₃(s) + HC₂H₃O₂(aq) → CO₂(g) + H₂O(l) + NaC₂H₃O₂(aq)
In order to determine the pressure of CO₂ in the cylinder, the vapor pressure of water at 21oC must be ______."
