How to find out # of e -gained or lost in e- configuration

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

In 2002, the rare earth elements mine in mountain pass, california was closed because

What does the symbol (–hfus) indicate in a phase change?