The hydrogenation of ethene gas under standard conditions (T=298K) shows a decrease in disorder (delta S = -0.1207 kJ/mol x K)) during an exothermic reaction (delta H degrees = -136.9 kJ/mol). Determine whether the reaction is spontaneous or nonspontaneous by calculating delta G degrees.

C2H4 (g) + H2 (g) -> C2H6 (g)

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. the ph lowers slightly but is approximately unchanged, and still remains acidic. what can you say about the solution? a. it is a buffer solution. b. it is not a buffer solution it is a strong acid solution. d. the solution has been neutralized. e. the solution has excess acid present