<span>When pKas of polyprotic intermediates have a difference of 2 or more you just average them using the equation: pH = (pKa2 + pKa3) / 2 </span>
<span>pKa2 = -log(Ka2) ; pKa3 = -log(Ka3) </span>
<span>so, for this problem, REGARDLESS OF THE CONCENTRATION GIVEN, the answer is: </span>
<span>pH = (7.2076+12.3767) / 2 </span>
<span>pH = 9.79</span>
Exothermic is when energy is released
endothermic is when its being absorbed<span />
A) true
b) false The atomic mass is never less than the atomic number.
c) this one is a bit tricky. For hydrogen, the atomic mass can equal the atomic number IF you are rounding the mass to the nearest whole number. That only works for hydrogen, though
d) false The larger the element, the more neutrons that are needed to keep the nucleus stable.
e) true
f) true
Atomic no = no of electrons present in atom
and atomic mass = no of protons + no of neutrons
