I don't have any worksheets but I can try to explain some of these concepts.
determining moles of ions: Easy - just multiply or divide by Avogadro's number, the # of molecules in 1 mole of anything. It's 6.022x10^23.
Example - how many moles is 4.8x10^20 atoms?
Set up: 4.8x10^20atoms(1mol/6.022x10^23 atoms) = mol, since atoms cancels
the math becomes division, 4.8x10^20/6.022x10^23 = 8x10-4 mols (0.0008 mols)
Determining molarity: Simple formula. Molarity = moles of X/Liters solution. Always.
If your amounts aren't in moles or liters you have to convert.
Example: 0.42 moles of X are mixed in 350ml of solvent. What's molarity (M)?
M=.42 mols/.35L = 1.2 M
Writing ionic equations:
This is simple stoichiometry, usually a double displacement problem.
Double displacement formula: AB + CD --> AD + CB
Example: HCl + NaOH ---> H2O + NaCl
A+D becomes HOH, which is H2O... and C+B = NaCl. Then you just have to balance them.
This one happens to be balanced.
Ionic formulas are based on oxidation numbers/charges. All molecules combine to try to get a zero charge, so it's a factoring problem as far as math goes. H is +1, OH- is -1 charge, so together they cancel to make neutral H2O. If it was NH3, ammonia, for example, N is group 5, so a -3 charge, and H is group 1, +1 charge in this case (H can be +1 or -1, depending on what it bonds with), so you need 3 of them to balance the -3 charge to get to zero.
Here's a great periodic table that even does electron configuration: http://www.ptable.com
The groups have different charges based on their valence electron shells. A group is a vertical column on the table. Group 1, 2, 3 and 4 have +1, +2, +3 and +4 charge, respectively (group 1 = +1, group 2 has +2, etc). Group 5, starting with N is -3, Group 6 = -2, group 7 -1 charge, and the noble gases, group 8, have no charge.
As far as electron configuration goes, groups 1-2 end in S, transition metals end in D, groups 3-8 end in P, and actinide series under the main table end in F.
Oxidation numbers: These follow the charges for the most part, as outlined above. Transition metals can change their oxidation numbers. H and O are usually figured out first in any molecule, because they never change. O is always -2, and H is always +1.
Therefore... H2O = O is -2, and H is +1(x2=+2)... 2+ -2 = O, the charge on the molecule.
HNO3 ... H is +1, NO3 as a molecule is -1 (certain oxidation number/charges you just have to memorize, includes almost all of the -ites/ates). 1+ -1=O
In this case you would NOT try to find the oxidation of N, for example, because it is not considered a lone atom, but a molecule of NO3-.
Oxidation and Reduction: This depends on whether you are in Inorganic chem or Organic chem.
In inorganic chem, remember OILRIG. Oxidation is loss, Reduction is Gain. It refers to electrons. In inorganic, oxidation is the LOSS OF ELECTRONS, causing the INCREASE IN POS CHARGE, because electrons are negatively charged (-1). Losing one makes the charge go UP.
Here's an example stoichiometry of a redox reaction. In redox, elementals are ZERO charge.
3H2 + N2 ==> 2NH3
Which is oxidized and which is reduced?
Both elementals on the left are at zero charge.
However, in NH3 on the right, N is -3 and H is +1.
H -- NH3... H went from 0 to +1, a LOSS of an electron = oxidation
N -- NH3... N went from 0 to -3, a GAIN of electrons = reduction
In Organic chem, oxidation is the ADDITION OF OXYGEN to a reaction with a loss of hydrogen or a halogen (group 7 element). Reduction is the corresponding ADDITION OF HYDROGEN with a loss of oxygen or halogen. I doubt you are there yet.
There are several forms of naming, but the easiest in inorganic is the ionic form.
You name the first element of the compound, and then the second element you use the 1st syllable and IDE as the ending.
You also have to take into account how many atoms of the 2nd element there are, and there are prefixes for that number.
1 = mono (not always used)
2=di 3=tri 4= tetra
5= penta 6=hexa
7= hepta 8= octa
Hence... NaCl... Na = SODIUM, Cl = CHOR-IDE... Sodium Chloride! Table salt.
CO = Carbon MON-OX-IDE
CO2... Carbon DI-OX-IDE
H2SO4... DI-Hydrogen sulfate, also known as sulfuric acid
This website should help. It's got some organic chem stuff, just ignore that... but alot of inorganic naming help.
Well, hope this helps... Remember inorganic chem is 90% algebra, and you should be fine. Just memorize the formulas.
· 8 years ago