July 09, 2020, 01:57:40 AM
Forum Rules: Read This Before Posting


Topic: Writing chemical equations  (Read 5716 times)

0 Members and 1 Guest are viewing this topic.

Workaholic

  • Guest
Writing chemical equations
« on: April 24, 2005, 09:46:30 AM »
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!

 

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25833
  • Mole Snacks: +1690/-401
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re:Writing chemical equations
« Reply #1 on: April 25, 2005, 05:50:12 AM »
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.
Quote
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.

Quote
1)SiCl4 + H20 = ??

My intuition tells me - either nothing, or hydrolysis to SiO2 plus HCl. Probably the latter.

Quote
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.

Quote
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 :)
« Last Edit: April 25, 2005, 05:51:52 AM by Borek »
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7390
  • Mole Snacks: +516/-86
  • Gender: Male
Re:Writing chemical equations
« Reply #2 on: April 25, 2005, 07:06:02 AM »
Quote
1) Acid + Reactive Metal = Salt + H20
Above is a ore serious mistake - hydrogen should be instead of water

Quote
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.
AWK

Sponsored Links