What is the (H3O+) for a solution whose pH is 5.42

What is common about these molecules? a.their atoms are held together by covalent bonds. b.they are all made up of the same two atoms. c.their atoms are held together by ionic bonds. d.they are all made up of oxygen atoms only.

Apeak with a retention time of 407 s has a width at half-height (w1/2) of 7.6 s. a neighboring peak is eluted 17 s later with a w1/2 of 9.4 s. a compound that is known not to be retained was eluted in 2.5 s. the peaks are not baseline resolved. how many theoretical plates would be needed to achieve a resolution of 1.5?

State one important difference between a physical change and a chemical change?