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Law of Conservation of Mass - Atoms cannot be created or destroyed!
...How is that even relevant?
-This is the basis for balancing chemical equations because what goes into a chemical reaction must also come out. Meaning, not only can't atoms be created or destroyed, but also that they must get rearranged in an equation. History: Before the people understood the law of conservation of Mass people believed in spontaneous generation, an idea that things could just appear randomly like maggots coming from meat (they did not know the life cycle of the fly that had to land on it and lay eggs for maggots to appear).
-Balancing an equation is like figuring how much you need of your reactants (at the very least) to get a given amount of a product. It's all about accountability and good book keeping!
Info you should know before you start balancing equations...
Chemical Formula - Shorthand for writing molecules and compounds
example: H2O
A few rules for these...
Video for balancing equations:
Work the problems along side him for best results & understanding!
Don't just blindly watch; if you are confused: PAUSE, take a note, rewind and watch slowly until YOU make sense of it. Nobody can make sense of the world for you!
Subscripts:
Subscripts are the small number. That tells you how many of a specific atom there is
example NH4
N = 1 atom H =4 atoms
Coefficients
Numbers coming before a compound are coefficients they are multipliers (they tell you how many molecules you will need). Use distributive property.
3NH4
totals:N= 3 H=12
Note if there are no numbers provided, assume it is a 1 for coefficient
-You can change the coefficients
-Coefficients represent Moles
Parenthesis
Parenthesis appear and are used as a multiplier for sections of a molecule
Al2(NH4)2
totals: Al = 2 N= 2 H=8
If there is a coefficient, multiply it times the parenthesis
3Al2(NH4)2
totals: Al = 6 N= 12 H=16
~~~~[You should understand he above before proceeding!]~~~~
Chemical Equation - shorthand of writing a chemical reactions.
A "balanced" chemical reaction means that the totals for each atom is the SAME on both sides of the equation.
Make a tally of each element on the reactant side and the product side
You can change the coefficients before a formula not subscripts.
BE FEARLESS AND CHANGE THOSE COEFFICIENTS!!!
Tip: start low. If there is no coefficient it is assumed to be a one. Coefficients multiply times each element in the molecule.
When you change a coefficient update your tally for each element
When all of the elements are the same your equation is balanced.
See video for now, more to come soon :-)
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