Question

When determining the equilibrium concentrations for the reaction
`AB(g) \rightleftharpoons A(g) + B(g)`;
`K_c = ([A][B])/([AB])` a simplifying assumption can be used under certain conditions to avoid solving a quadratic equation.
`K_c = (x^2)/([AB]-x) \approx (x^2)/([AB])`Classify each situation by whether the simplifying assumption can be used or whether the quadratic formula is required.Use simplifying assumptions - Quadratic formula required 1. [AB] = 0.0178 M;
`K_c = 2.35 x 10^(-6)`2. [AB] = 0.00204 M;
`K_c = 1.52 x 10^(-6)`3. [AB] =0.451 M;
`K_c` = 0.000905 4. [AB] = 0.0174 M;
`K_c` = 0.0000925 5. [AB] = 0.396 M;
`K_c` = 0.00228

Answer 1

When the value of the equilibrium constant is much smaller than [AB], simplifying assumption can be used.

However, if the value of the equilibrium constant is closer to [AB], quadratic formula is required.

Step-by-step explanation:

see picture