You have a 100. ml of a 0.25 M K2SO4 stock solution, You want to create a 0.10 M solution you would have to add water until what new volume would be reached?

i think slash and

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.

the electron configuration that you gave me has 16 electrons ergo it has 16 protons ergo it is the element sulfur.