Gas Stoichiometry Non-Standard Conditions

The relationship between volume and moles (n)

Stating the relationship

Avogadro’s Hypothesis Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.

Molar volume of a gas 22.4 L per mole gas at STP

C 3 H O 2  3 CO H 2 O If 25 liters of oxygen are consumed in the reaction above at STP, how many liters of carbon dioxide are produced?

Nonstandard Conditions Gas volume changes dramatically when pressure or temperature change. Key: mole to mole conversions aren’t affected by pressure or temperature.

Doing the Calculations Given a volume of gas at other than STP? – Convert to STP or find moles of gas before doing the mole-mole calculation. Finding the volume of gas at other than STP? –Do the mole-mole conversion, then convert the volume to stated conditions

Problem 1 What volume of chlorine gas measured at 18.5 o C and 98.0 kPa can be produced by the electrolysis of 62.3 g of NaCl to give sodium metal and chlorine gas? Answer: 13.2 L