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Gas Stoichiometry Ideal Gas Law. Putting it all together…. Balance the following equation…. C 8 H 18 (l) + O 2 (g) → CO 2 (g) + H 2 0(g) 2 C 8 H 18 (l) + 25 O 2 (g) → 16 CO 2 (g) + 18 H 2 0(g) Coefficients of balanced equations can be used as mole ratios in stoichiometry problems.
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Gas Stoichiometry Ideal Gas Law Putting it all together…
Balance the following equation… • C8H18(l) + O2(g) → CO2(g) + H20(g) • 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H20(g) • Coefficients of balanced equations can be used as mole ratios in stoichiometry problems
Mass-Mass Stoichiometry • Problem 11.13 c (p.332) • Mg + HCl → H2 + MgCl2 • 60.1 g HCl
Volume Ratio = Mole Ratio • Problem 12.85 (p.373) • 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)
Avogadro’s LawOne mole of a gas will occupy 22.4 L • This means that the mole ratio is the same as the volume ratio
Volume Ratio = Mole Ratio • Problem 12.85 (p.373) • 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) • 200. L O2
Volume Ratio = Mole Ratio • Problem 12.85 (p.373) • 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) • Problem 12.81 (p.373) • 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2H2O(g) • 2.5 tanks O2
Gas @ STP • Problem 12.92 (p374) • NaN3(s) + Fe2O3(s) → Na2O(s) + Fe(s) + N2(g) • 6 NaN3(s) + Fe2O3(s) → 3 Na2O(s) + 2 Fe(s) + 9 N2(g) • 10.6 g NaN3
Standard Molar Volume • The volume of 1.0 mole of any gas at STP is 22.4 L. • This is called the standard molar volume. • The volume of any gas at STP can be calculated if the number of moles is known: • V = (moles)(22.4 L)
Gas Not at STP • Problem 12.88 (p.373) • CaC2(s) + 2 H2O(l) → Ca(OH)2(s) + C2H2(g)
Ideal Gas Law • All of the variables used to describe gases can be compared using the Ideal Gas Law • The IGL is often called an equation of state, as it is very useful when finding some property of a gas at a certain condition • Not so great when conditions are changing • Entropy is another condition of state
Ideal Gas Law • PV = nRT • P = pressure • V = volume • T = temperature • n = number of moles of gas • R = Gas Constant • value depends on the desired unit
Gas Constant (“R”) • R is a constant that is used in the IGL so that it may be used for all gases • It has a different value, depending on the pressure unit being used in the problem
Gas Not at STP • Problem 12.88 (p.373) • CaC2(s) + 2 H2O(l) → Ca(OH)2(s) + C2H2(g) • 960 ml C2H2 • Problem 12.90 (p.373) • 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H20(g)
Gas Not at STP • Problem 12.88 (p.373) • CaC2(s) + 2 H2O(l) → Ca(OH)2(s) + C2H2(g) • 960 ml C2H2 • Problem 12.90 (p.373) • 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H20(g) • 837 L CO2