Textbook Question 5.35

[Lily Zello 3I]

For textbook question 5.35, you are given a chart that shows the partial pressures of compounds A, B, and C over time. How do you know what the stoichiometric coefficients are for the balanced equation? I looked in the back of the book and it has 2A(g) —> B(g) + 2C(g).

[Sophia Olender 2J]

Looking at the graph, the changes in pressure from initial state to equilibrium (when the lines stabilize) are ΔA = 10, ΔB = 5, and ΔC = 10. The simplified ratio of change in A:B:C would then be 2:1:2. This ratio provides the coefficients for the reactants and products in the equation and since this is decomposition of A into B and C (pressure of C and B start at 0), the equation would be 2A --> B + 2C.

[Kaitlin Eblen 1I]

If it's more familiar, you can also set up an ice box with the initial and equilibrium concentrations. By looking at whether it should +/- x or 2x based on these states, you can deduce the balanced chemical equation.