C7H16 + 10 O2 = 6CO2 + 8H2O
2PbS + O2 = 5S + 2PbO
To name the compounds look at carbon compounds. The beginning of the word tells you how many carbons:
meth = 1, eth = 2, prop =3, but = 4, pent = 6, hex = 6, hept = 7, oct = 8, non = 9, dec = 10. Then look at the ending. "ane" = saturated hydrocarbon - all carbons bonded together with single bonds and the rest of the open bonding sites taken up with hydrogens. The formula is CnH2n +2 where n= number of carbons. You have hept = 7 carbons and "ane" = saturated hydrocarbons. If the ending is "ene" that means there is 1 double bond between 2 of the carbons in the chain and the formula for an "ene" is CnH2n. Then your name would be heptene. If there are 2 double bonds between carbons in the chain, the ending would be "diene" and you would have heptadiene. The formula for this is CnHn
Oxygen (O2)is one of 7 diatomic molecules (di=2, atomic = atoms) where, unless they are ions, they always appear in pairs - never alone. You can remember them by the name Cliff Brown. Spelled chemically it would be Cl (chlorine),
I (iodine) F (fluorine) Br (bromine) O (oxygen) H (hydrogen) and N (nitrogen) = ClIF BrOHN
Following the formula I gave you for an "ane" the formula is C7H16 (CnH2n +2) and oxygen is diatomic so it is O2. These are called reactants. The products are on the right side of the equal sign and you already know they make CO2 and H2O. You need to list the elements you have on each side of the equation and how many of each. For instance you have 16 hydrogens )H16) on the left side and only 2 on the right. Put an 8 infront of the H20. Now your hydrogens are balanced. The 8 gives you 8 oxygens. and you know that CO2 gives you 2 oxygens so you have 10 on the right side. You go back and forth like that putting numbers in front of compounds or elements until you have the same on each side. Some are easy and some are terrible with 32 of one thing and 18 of another. Go to this web site and it will not only balance your equationf for you but also tell you if they are impossible and why:
http://www.webqc.org/balance.php
If you are putting other elements together to form a compound try using the following explanation. Lead (ll) sulfide (look up formula on wikipedia) has the formula PbS. Lead has 2 oxidation numbers, +2 and +3. We know that we are using the one with an oxidation number of +2. Sulfur comes from group 16 on the periodical table and that group has an oxidation number of -2. So since one is +2 and the other is -2, they fit together perfectly. What if you are told to use lead (lll) and make lead oxide. Then the oxidation number of lead would be +3 and being in group 16, oxygen has and oxidation number of -2. To balance the compound write Pb and O. Put their oxidation numbers on top. A +3 over Pb and a -2 over oxygen. Now cross over. The Pb gets oxygen's 2 and oxygen gets lead's 3. Write the numbers after the chemical symbol as a subscript (at the bottom) and you come up with Pb2O3. To ckeck it out multiply the element's oxidation # with the number in the subscript. For lead it would be 3 x 2 = 6. For oxygen it would be 2 x 3 = 6. They balance! If you go to the web site I gave you, this will not balance the compounds you make by putting elements together. Keeping in mind oxidation numbers, put your compounds together, balance them THEN balance the equation.
Tidbit: Go to the periodic table. Group 1 has an oxidation number of +1. Group 2 is +2. Group 3 is +3. Group 4-13 can have all different numbers and some (like lead) have more than one. If you look up the element and it has more than one, unless you are told otherwise, use the lowest number. Group 14 has a + or - 4. Group 15 has a -3. Group 16 has a -2. Group 17 has a -1. Group 18 are noble gases. Their outer (valence) shell is full with 8 electrons so it has no oxidation number and doesn't bond with anything.
When combining compounds and writing out an equation, there are several different types of reactions. In a single replacement reaction the formula is A + BC = B + AC. Say you are combining Sodium with Hydrochloric acid. The formula for the reactants is Na + HCl. To geth the product, designate elements as the letters in the formula. Na would be A, H would be B and Cl would be C. Now use the formula which says the product is B + AC. So your product is Hydrogen and NaCl. Na has an oxidation number of +1 and chlorine is -1 so they fit together perfectly. Hydrogen is a diatomic molecule so it is H2
A double replacement reaction is when you combine 2 compounds and the formula is AB + CD = CB + AD. Label your parts and combine them according to the formula, keeping in mind their oxidations numbers as you do so. An example would be NaOH (sodium hydroxide) with HCl (hydrochloric acid). Na would be A, OH would be B, H would be C and Cl would be D. Use the formula and you get OHH (H2o = water) and NaCl (sodium chloride - table salt).
A combination reaction is just putting 2 things together and its formula is A + B = AB
A decomposition is where one compound breaks up into 2 or more compounds. There are more products than reactants.
A combustion reaction is between a fuel and oxygen. Fuels are carbon, hydrogen, sulfur, coal, oil and gas. The formula is : fuel + O2 = H2O + CO2 = heat.
The last type of reaction is an acid - base reaction. You combine and acid and base and get a salt and water. An example of this is the ingredients I gave you in the double replacement reaction. Sodium hydroxide is a base, hydrochloric acid is an acid (obviously) and they form a salt (NaCl) and water (H2O)
I hope this information has been of help to you, especially about how to put two elements with different oxidation numbers together. Good luck!