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Chemistry 2710 Spring 2000 Quiz 4 solution

Pressures and concentrations are proportional by

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To completely use 40kPa of A takes 80kPa of B. A is therefore in excess. When 30kPa of B have been used up, the pressure of A will have decreased by 15kPa, i.e. the partial pressure of A will have dropped to tex2html_wrap_inline59 . The rate constant is given in concentration units. We should therefore convert the initial and final partial pressures of A to concentration units:

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Now we just need to solve the integrated rate law for t:

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The total pressure can be found by stoichiometry. Again we recall that the reaction uses up 15kPa of A (leaving 25kPa) to completely consume the second reactant. When this much A has been used, 15kPa of the product P is formed. Thus the total pressure is

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Marc Roussel
Mon Feb 7 08:22:15 MST 2000