Balancing an equation

To balance a chemical equation is very difficult at times especially when multiple elements and compounds are involved

First you need to figure out what you have here i will show you a balanced equation and give you step by step instructions on how I got there

2H2+1O2=2H20

pretty simple this is the balanced equation for water now lets do something a bit more tricky I have three molecules of hydrogen a surplus of of chlorine and need to know how much hydrogen chloride i will yield from combining them

3H2+?Cl2=?HCl

First off we need to know how much hydrogen it takes to fulfill chlorine's octet it takes one electron for chlorine to reach and octet be it being a group7 element and hydrogen being group one wants to give one away so they combine on an even ratio meaning it takes 3 molecules of chlorine and you get 6 HCl (wait a minute how did that happen). You see hydrogen and chlorine are both diatomic meaning you rarely find just H or Cl you will mostly find H2 or Cl2 due to their nature so you have to multiply the product result by 2 in order to maintain the law of conservation of matter.

Your end result should be

3H2+3Cl2= 6HCl

what if you have elements with opposing charges though that means you will have to have different coefficients no worries i will show you an example of that

3C+6Cl2=3CCl4


Carbon has a charge of plus or minus 4 chlorine has a charge of -1 it just needs one electron to satisfy its octet carbon needs to give away 4 to satisfy what it needs so it will take 12 Cl atoms to satisy 3 C atoms thus giving you a carbon chlorine ratio of 1/4 which is how i derived CCl4

please comment if you have any questions