1. a student has 200 ml of 50 mm hepes buffer, ph 7.0. the pka of hepes acid is 7.56.
a. they add 2 ml of 0.5 m naoh to the solution. what is the ph of the resulting solution?
b. they then add 20 ml of 0.5 m naoh to their new solution from part a. what is the ph of the resulting solution

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?

Which of the following natural processes is most likely to support the formation of an underwater sinkhole? a pollution buildup from deposited minerals b limestone cave collapsing due to changes in sea level c erosion of large amounts of sand moved by ocean waves d oxidation of rock formed by chemical weathering

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.