please help?

Question

What's the easy way to remember inorganic reaction?I find very difficult to remember them .please tell me any way or tricks to remember reactions.It will be very helpful for me.

Answer 1

For inorganic reactions, try to remember the most common elements' position in periodic table.
Try to memorize the first three periods completely.
This will help you remember the atomic numbers.
You will also remember the charges of cations because of this.

You will then be able to guess the charges on anions too.

After you have mastered all thes go on to the reactions, then they would seem far more logical , and you NEED NOT MEMORIZE them.
Also prepare your concepts on Oxidation number.

Answer 2

I would recommend that you break reactions down by type, learn oxidation numbers and ion charge, memorize strong acid/bases and memorize polyatomic ion names, formulas and charge.

This may seem like too much, but I assure you that it is less info than you might think. If you devote time to each 'piece of the puzzle', you will build your confidence and know how to determine what's important in each reaction.

Start by letting the periodic table 'be your friend'! Use the columns to determine ionic charge (ie. column IA = +1, IIA= +2, IIIA= +3, IVA= no charge, VA= -3, VIA= -2, VIIA= -1 and VIIIA= 0).

Oxidation numbers are based on ionic charge, so add just a few rules: oxygen is always -2 unless in H2O2 (hydrogen peroxide), when it is -1; metals (columns I-IIIA) always form charge of their column number; you can determine charge of transition metals by oxidation number rules (is. Cu2O3: oxygen is -2, so multiply by number of oxygens to get total charge= -6; now divide that charge by number of copper ions = +3). Use the atoms that have constant ox number to determine other ion ox numbers.

Polyatomic ions are your next task. When I was a chem student, I memorized the rules and then memorized only one of the possible polyionic forms, ie. -ate endings vs. -ite endings: -ite always has one fewer oxygen (sulfate = SO4-2, sulfite = SO3-2) and the charge for each species is always the same (both sulaite and sulfate are -2).

There are also a few interesting polyatomic species that have 3 or 4 possible formulas, ie. perchlorate (HCO4)-1, chlorate (HCO3)-1, chlorite (HCO2)-1, and hypochlorate (HCO)-1. Remember that hypo=under or below and that 'per' comes from the prefix 'hyper-' which means above or excess.

Just memorize formula and charge of one of each of the common polyatomic ions. Use the rules to determine name and charge. I personally memorized the -ates.

Types of reactions to be able to ID: acid/base (water is a product), single and double replacement (always have metals, and they switch places between reactants and products), synthesis (A + B -> C) and decomposition (AB -> A + B), combustion (CO2 and H2O are products).

Now work on the strong acids and bases. There are only about 8 total to remember, so if you see an acid/base rxn if it isn't strong (which you have memorized) then it must be weak!

I hope this helps. This is how I got through this part of chem, and I still can use this info 10 years later, even tho I don't use chem much.

Answer 3

For beginners the types of simple reactions can be divided into categories depending on what the reactants are.

1. Synthesis: the reactants (usually two elements) combine to form one product.
ex. 2Ag + Cl2 = 2AgCl

2. Decomposition: the reactant is one compound and it breaks apart into (usually) two products.

a. metallic carbonates = metal oxide + CO2
CaCO3 = Cao + CO2
b. metallic hydroxides = metal oxide + H20
Cu(OH)2 = CuO + H20
c. metallic chlorates = metal chloride + O2
2 NaClO3 = 2NaCl + 3O2
d. acids = water + nonmetal oxide
H2SO4 = H2O + SO3
e. binary compound = individual elements
KCl = K + Cl2

3. Combustion: a hydrocarbon reacts with oxygen to form water and CO2. (a hydrocarbon is a compound of carbon and hydrogen)

CH4 + 2O2 = 2H2O + CO2

4. Single replacement: the reactants are one element plus one compound. If the element is a metal it replaces the metal part of the compound. If the element is a non-metal it replaces the nonmetal part of the compound.

a. Zn + 2HCl = ZnCl2 + H2
b. Br2 + 2NaCl = 2 NaBr + Cl2

5. Double replacement: the reactants are two compounds. The metal parts of the two compounds exchange places.

AgNO3 + NaCl = AgCl + NaNO3

If you master these 5 categories you can later go on to add the more complex reactions.

Answer 4

Well, most inorganic reactions(the ones in laboratory) are carried out in solution. So most of them involve double displacements of ions. In the case of redox reactions, it really works if prepare a table of common oxidants(acidified KMnO4, H2O2, etc) and reductants(HCl, NH3, etc) and the oxidation and reduction reactions involved. You can write down any reaction by adding the two relevant half-reactions(which aren't difficult to remember).