All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: A mixture of NH3(g) and N2H4(g) is placed in a sealed container at 320 K . The total pressure is 0.49 atm . The container is heated to 1200 K at which time both substances decompose completely accordi

Solution: A mixture of NH3(g) and N2H4(g) is placed in a sealed container at 320 K . The total pressure is 0.49 atm . The container is heated to 1200 K at which time both substances decompose completely accordi

Problem

A mixture of NH3(g) and N2H4(g) is placed in a sealed container at 320 K . The total pressure is 0.49 atm . The container is heated to 1200 K at which time both substances decompose completely according to the equations 2 NH3(g) → N2(g) + 3 H2(g); N2H4(g) → N2(g) + 2 H2(g). After decomposition is complete the total pressure at 1200 K is found to be 4.5 atm.

Find the percent (by volume) of N2H4(g) in the original mixture. (Assume two significant figures for the temperature.)

Solution

First, we set variables for the moles of each reactant:

We can add them up to get the total initial moles reactant. 


Next, we use these variables to express the amount of product by doing a mole to mole comparison using the coefficients of the balanced reaction. The mole products are just the sum of its coefficient per reaction. 

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