An element has two isotopes, A and B, with mass numbers of 32.0 and 33.0 respectively. The relative atomic mass is 32.3. The percentage abundance of the two isotopes is: a) A - 20% B - 80%

b) A - 25% B - 75%

c) A - 80% B - 20%

d) A - 70% B - 30%

e) A - 50% B - 50%

The following questions a24 - a26 relate to 100 ml of 0.0150 m solution of benzoic acid (c6h3cooh). ka(c6h3cooh) = 6.4 x 10^-5. what is the ph of the solution after the addition of 1 x 10^-3 moles of naoh? you may assume no volume change to the solution upon addition of the naoh.