a 100g sample of a fertilizer contains .0705 moles of p2o5 and .106moles of k2O how many moles of p and k are in the sample.
please explain how
thanks
2007-09-18 09:21:02 · 4 answers · asked by ilikegcalot 1 in Science & Mathematics ➔ Chemistry
well for each mole of P2O5 you'll get 2 mole P
so if you have 0.0705 mole P2O5 you'll get
2*0.0705 = 0.141 mole P
similarly
each mole K2O give 2 mole K
0.106 K2O ==> 2 * 0.106 = 0.212 K
2007-09-18 09:28:17 · answer #1 · answered by Dr Dave P 7 · 1⤊ 0⤋
The answer is based on the number of atoms in the molecule.
P2O5 has 7 atoms in total. 2 of the seven atoms is "P", so this accounts for 2/7 or roughly 29% of the total. If there are .0705 moles of P2O5, then 29% of this is also "P". A mole is actually a number and therefore 29% of .0705 is 0.01 moles (.29 times .07).
The K2O is worked out exactly the same way. The fact there is 100 grams is not relevant, because the question is about moles, not weight.
2007-09-18 16:31:20 · answer #2 · answered by Roger S 7 · 0⤊ 0⤋
The key to this question is just ratios. If I have 0.0705 moles of P2O5, then for each mole of P2O5 I have 2 moles of P.
With the K2) compound it's exactly the same, each mole of K2O contains 2 moles of K
2007-09-18 16:29:58 · answer #3 · answered by Stephen R 2 · 0⤊ 0⤋
0.0705 x 2 moles of P and 0.106 x 2 moles of K. Look at the numbers written after the P and the K in the formulas.
2007-09-18 16:28:17 · answer #4 · answered by Gervald F 7 · 0⤊ 0⤋