could you explain how you got the answer
2006-11-19 23:40:15 · 4 answers · asked by Becky W 1 in Science & Mathematics ➔ Chemistry
N=aM where a in the case of acids is the number of H+ the molecule can give (regardless if it is a strong or weak acid)
so N=aM=3*0.20=0.60
a for a base would be the number of OH- it gives (or number of H+ that it receives), whereas for redox reactions the number of electrons gained/lost during the reaction or if you prefer the change in the oxidation number
2006-11-20 01:31:41 · answer #1 · answered by bellerophon 6 · 0⤊ 0⤋
First, you can convert molarity to number of moles by assuming this is a 1 L solution.
(0.20M)(1L) = 0.20 mol.
Since you have 3 protons that can be donated by H3 PO4, this is equal to 3 equivalents/mol. An equivalent is the amount of substance that can donate or accept electrons, and protons accepts electrons. By knowing this information, you multiply the number of equivalents/mol by the number of moles.
(0.20 mol)(3 equivalents/mol) = 0.60 equivalents.
Now you divide by the original volume to get normality.
0.60 equivalents/ 1L = 0.60 N
2006-11-20 08:51:57 · answer #2 · answered by Carlos L 1 · 0⤊ 0⤋
Difficult to calculate. You would think you could just multiply the .2 X 3 H, but only the first H will ionize completely. The other 2 H have low Kpa.
2006-11-20 08:49:29 · answer #3 · answered by Anonymous · 0⤊ 1⤋
I am amazed that anyone is still using normalities. We haven't used them in UK schools for more than 30 years.
Molarity is a much more useful concept.
2006-11-20 13:16:23 · answer #4 · answered by Gervald F 7 · 0⤊ 0⤋