by **goldstanda3269** » Tue Nov 05, 2013 8:53 pm

"Also how important is this concept for the GAMSAT."

- They would never ask "what is normality?" or "calculate the normality" without first using the standard definition as presented in the book. Likewise they can present a new concept but as long as you are comfortable with dimensional analysis then you can follow many real GAMSAT questions to their solutions without knowing any specific formula.

Key points:

1) M = molarity = moles/liter

2) N = normality = equivalents of acid or base/liter

3) HCl has 1 acid equivalent; H2SO4 has 2 acid equivalents; NaOH has 1 base equivalent (i.e. OH-)

So if you have 2.3 M of HCl then it's the same as 2.3 N of HCl. Because:

2.3 moles HCl/liter * I equivalent of acid/ mole HCl and since moles HCl cancels, you get:

2.3 equivalents of acid/liter = 2.3 N HCl

Using the same logic, if it were 2.3 M H2SO4, because there are 2 reacting units of acid, it would be equivalent to 4.6 N H2SO4.