I did a lab, but I can't figure out what was made in the reaction because there are so many possibilities. Magnesium was put into a crucible and reheated many times until no reaction (the Mg strip burning or lighting up) was made. Of course, air is not only oxygen. It also has nitrogen in it so it also could have made a different formula than MgO. So what is the formula for this compound?
Also, it was later grounded up and put with water, then burned again until a small vapor came up. This also might have created a new compound, and I have no idea what it is other than MgO with H2O molecules. Any help would be appreciated.
2006-11-30 16:29:35 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
2Mg+O2-->2MgO
2MgO+2H2o---->2Mg(OH)2
2006-11-30 16:35:57 · answer #1 · answered by yupchagee 7 · 16⤊ 1⤋
When you burn Mg in air, it will mostly be oxidised by oxygen to form MgO, which is a white compound. And the Mg probably burned with a dazzling white flame, didn't it? Those two observations should prove that the product is indeed MgO.
When you react MgO with hot water, a small amount of Mg(OH)2 may well be formed. But this reaction is not very feasible and I doubt that you have obtained any of it actually. Mg(OH)2 is white powder as well but has a high boiling point, so I would say that the vapour you observed is indeed water vapour and nothing other.
2006-11-30 17:22:09 · answer #2 · answered by notscientific 2 · 0⤊ 0⤋
When something is burning, the only element in the air that is reacting is oxygen. So the only compound that would have been created would always be the magnesium oxide that you thought should have been made. The vapor that you saw when you mixed it with water was probably just water vapor evaporating from the crucible. MgOH2 cannot be created through this reaction because hydrogen can't be introduced into a compound through combustion, only oxygen.
2006-11-30 16:44:10 · answer #3 · answered by Anonymous · 1⤊ 0⤋
Hi!
You were on the right track to consider other possibilities. Although most of your magnesium will end up as MgO, the heating of magnesium metal will make it a strong enough reducing agent to reduce nitrogen in the air and form Mg3N2 aka magnesium nitride.
And mixed with water, the MgO would form magnesium hydroxide as the other person answered before.
Cheers!
2006-11-30 16:56:00 · answer #4 · answered by timor_abesto 1 · 0⤊ 1⤋
You get two products, magnesium oxide and magnesium nitride. Magnesium oxide isn't very soluble. Magnesium nitride, however, reacts with water giving off ammonia gas, and sometimes this smell is very noticeable in this experiment.
Mg3N2 + 3H2O ---> 2NH3 + 3MgO
2006-11-30 18:30:46 · answer #5 · answered by Gervald F 7 · 0⤊ 0⤋