Which of the following will not have the same number of valence electrons?

carbon

silicon

lead

bismuth

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

This classification of drug typically changes the brain's chemistry and reduces its ability to create its own endorphins.

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?