Areaction is spontaneous if δg is
negative, positive, or zero?

A reaction is spontaneous if ΔG is negative.

Explanation:

If ΔG is negative, the reaction is spontaneous.

If ΔG = zero, the reaction is at equilibrium.

If ΔG is positive, the reaction is non-spontaneous.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.