Consider the energy level diagram sketch below.

Which of the transitions, a) to e), represents a hydrogen atom in its excited state emitting light and ending up still in an excited state?

In which of the following reactions would increasing pressure at constant temperature change the concentrations of reactants and products, based on Le Châtelier's principle?

Which one of the following will change the value of an equilibrium constant?

Nitrosyl bromide decomposes according to the following equation:

Dinitrogen tetroxide partially decomposes according to the following equilibrium:

K_c for this reaction is ________.

Consider the following equilibrium reaction:

H₂CO₃ (aq)  ⇌  H⁺ (aq) + HCO₃^– (aq);     K = 5.0 x 10^–7

 If the initial concentrations of the species are:

[H₂CO₃] = 0.020 M;   [H⁺] = 6.00 x 10^–5 M;   [HCO₃^–] = 4.00 x 10^–5 M

Which one of the statements below describes the relationship between Q and K and then the correct direction of chemical change?

The value of K for the following reaction is 0.25:

In a chemical reaction at equilibrium there is _______ in the concentrations of the reactants and products.

Choose the correct answer to complete the sentence above.

Which substance has the higher melting point?

Which of these two solvents below will the molecule below dissolve best in?