physical science notes (:

chemical reactions (review)

oh,
helLo,

So let's start us off with the age-old question of:
what is a chemical reaction ?

Well, boy, do I got a product for you !
(why yes that was an expertly crafted pun)

Definition of a chemical reaction
A chemical reaction in which one substance decides to be trans and forms a whole. new. substance.

SO, the new substance is referred to as product and the original substance is referred to as the reactants. This is uber easy because the reactants react together to form their final product.

Some examples of chemical reactions are :
• rusty rust rust
• fancy ass candles burning
• frying up some bird fetuses

         - Essentially, if you can't get back the original item, it was probably a chemical reaction (:

-Reactants + products can be single elements or compounds, it doesn't matter !

types of reactions

-there are 7 types of reactions
(but you'll only prob need to know the first 5)

•synthesis
-A + B -> C
synthesis occurs when 2+ simple compounds form to make something more complex
ex. 2CO2

•decomposition
-AB -> A + B
decomposition occurs when a complex molecule breaks down into a simpler one !!

ex. yeast but that's a long formula but if you look it up you'll get it, but you don't have to, just take my word for it (;

•single replacement
-A + BC -> AC + B
essentially an element just switches with another. the equation doesn't lose any matter or anything so it checks out.
ex. C + H ₂O -> Ca(OH) ₂ + H ₂
^ pro tip, that's the equation for Calcium Water which is super tasty (:

•double replacement
-AB + CD -> AD + CB
similar to single replacement, but a bit different.
anions ¹ and cations ² of two different equations swap their places, which creates an entirely new compound, that's freaking dope.

ex. CAKE ! (Baking soda reacts w acidic substances in the batter {yum} )

•combustion
-there's no basic ass equation for this
BUT, essentially what happens is oxygen combines with another element and this forms water and carbon dioxide.

ex. Propane:
C ₃ H ₈ + 5O₂ -> 4H₂O + 3CO₂ + ~energy~
^ you're welcome bitches that took for-frovking-ever to write out /:

•corrosion
-once again, no basic ass equation /:
BUT, corrosion happens when a metal reacts with the oxygen and the water in the air to usually form ~rust~.

ex. 2Fe + O₂ + H₂O -> Fe(OH)₂

•neutralization
-AB + CD -> AD + CB
this happens when an acid and a base react to form an ionic compound and water(:

ex. baking soda + vinegar

Energy
oof, so

THERE ARE 2 TYPES OF ENERGY IN A REACTION, pay attention kiddos bc this will be on your exam

-Endothermic
more energy is used to break bonds in reactants than is used to form new stuff , these reactions absorb energy from their environments

-Exothermic
more energy is used to form new stuff than to break bonds, these reactions release energy into their environments

ex. Wood burning bc it releases light + heat