How much oxygen would be needed to react with a 0.7986 gram piece of magnesium ribbon?
So, I know that the empirical formula is MgO. That is, 1 atom of Mg for every atom of O. I am brain dead right now.... please help me before I scream!!!
2006-09-17 16:38:56 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
step 1 : Must write chemical equation.
Mg + O2 --> MgO
step 2 : balance the equation.
2Mg + O2 --> 2MgO
step 3 : calculate number of moles of Mg.
no. of moles of Mg = (0.7986)/24.3 = 0.032864mol
(24.3 is Mr)
step 4 : mole ratio.
1 O2 reacts with 2Mg.
step 5 : calculate no. of moles of O2.
no. of moles of O2 = 0.032864/2 = 0.016432.
step 6 : calculate volume of O2 required.
in r.t.p molar volume is 24.0dm cube
in s.t.p molar volume is 22.4dm cube
(you did not mention in s.t.p or r.t.p. so i assume it's at r.t.p)
volume of O2 needed = 24 x 0.016432 = 0.39437(round off to 0.394dm cube)
hope this helped!:)
2006-09-17 17:58:15 · answer #1 · answered by siangal07 2 · 0⤊ 0⤋
If you divide the grams per the atomic weight you obtain the moles of Magnesium that will be 2 compared to Oxygen.
So, if you know that the moles of Oxygen are x/16 (16 is the molar weight of oxygen, you can easily solve per x, finding in this way the grams of oxygen you need as to complete the reaction
2 Mg + O2 = 2 MgO
2006-09-17 23:51:13 · answer #2 · answered by Fabrizio G 2 · 0⤊ 0⤋
Since the atomic weight of Mg is 24, 0.7986 g of Mg means 0.7986 / 24 = 0.033275 mole of Mg. This would react with 0.033275 mole of O (oxygen atom).
Now, one mole of O means 16 g of O.
So the mass of O that would react is
0.033275 X 16 g = 0.5324 g
The mass of oxygen gas (O2) that would react is also the same, since mass does not depend on whether the element is in atomic or molecular state.
2006-09-18 01:40:15 · answer #3 · answered by Problem Child 2 · 0⤊ 0⤋
Take 0.7986 divide by atomic weight of Magnesium = # moles of Mg
since 1mole of Mg reacts with 1mole of Oxygen
#moles of Mg=#moles of Oxygen needed
2006-09-17 23:59:54 · answer #4 · answered by Dianna 4 · 0⤊ 0⤋
Wouldn't it be 0.7986 grams of oxygen since it's a 1 to 1 ratio?
2006-09-17 23:49:47 · answer #5 · answered by God 3 · 0⤊ 0⤋
Mg + 0.5 O2 ---------- MgO
this shows that with one mole of Mg half mole of oxygen reacts,..
that is with 24 gms of mg 16 gms of oxygen reacts.........
so with o.7986 gms of mg.........7986*16/24 gms of oxygen is required.........
2006-09-18 05:23:06 · answer #6 · answered by !kumar! 2 · 0⤊ 0⤋
dont hold your breath...oxygen is vital
2006-09-18 00:25:15 · answer #7 · answered by sunflare63 7 · 0⤊ 0⤋