Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Workaholic on April 24, 2005, 09:46:30 AM
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I am learning how to write balanced chemical equations. I have mastered the art of balancing and writing equations. I experience no difficulty writing them out from word equations (and vice versa)
I also know how to balance and write redox and half ionic/ionic equations.
However Im having trouble when given the task of writing chemical equations when NO PRODUCTS are given to me. I can't seem to work out what is produced. I am fine when asked to write equations when the reactants and products are stated.
Are their rules about what is produced?
My tutor gave me general rules as follows:
1) Acid + Reactive Metal = Salt + H20
2) Acid + Base = Salt + H20
3) Acid + Metal Carbonate + Salt + H20 +CO2
But they don't help me with other problems such as:
1)SiCl4 + H20 = ??
2)Ca(OH)2 + 2NH4Cl = CaCl2 + 2NH4(OH) (is this rite, cus im guessing)
Please help as it is really holding me back!
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Are their rules about what is produced?
That's what the chemistry is all about ;)
There are general rules, but there are also tons of exclusions.
My tutor gave me general rules as follows:
1) Acid + Reactive Metal = Salt + H20
2) Acid + Base = Salt + H20
3) Acid + Metal Carbonate + Salt + H20 +CO2
You did a mistake writing third rule, but these are OK and should be helpfull.
In other cases you just have to know, or you have to develop some 'chemical intuition' - whatever it means.
1)SiCl4 + H20 = ??
My intuition tells me - either nothing, or hydrolysis to SiO2 plus HCl. Probably the latter.
2)Ca(OH)2 + 2NH4Cl = CaCl2 + 2NH4(OH) (is this rite, cus im guessing)
More or less OK. To be precise I will write not NH4(OH) but NH3(aq) + H2O.
Please help as it is really holding me back!
Don't bother too much - if there will be a closed set of rules describing what are reaction products, chemists will be an extinct species :)
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1) Acid + Reactive Metal = Salt + H20
Above is a ore serious mistake - hydrogen should be instead of water
2)Ca(OH)2 + 2NH4Cl = CaCl2 + 2NH4(OH)
Ca(OH)2 is poorly soluble in water, but this is a strong base, ammonia is a weak base, hence reaction proceeds, even quantitatively, when solution is warmed to remove ammonia. This is an ammonia regeneration process in Na2CO3 production by a Solvay method.