revision: Chemistry - Topic 1 - Energy

Energy is the source of power for everything, basically.
There are many different types of energy, and energy allows us to do things.
However, Energy can never be created nor destroyed, it can only be changed or transformed into a different form. So, it simply changes from one form to another.
This is the law of energy: it can't be created or destroyed.

TYPES OF ENERGY-
-Potential Energy (stored energy) -Chemical potential, elastic potential, gravitational potential
-Thermal Energy
-Kinetic Energy
-Light Energy
-Electrical Energy
-Sound Energy
-Nuclear Energy

HEAT AND TEMPERATURE-
Temperature is the amount of energy in an object.
Heat is the amount of energy stored in an object and Kinetic or Potential.
Remember ->  Heat = Stored  - I remember SH** -.- Yes, that IS how I remember.

Exo-thermic -> Energy is given out into the surroundings and there is temperature increase. (eg. combustion)
Endo-thermic -> Energy is absorbed from the surroundings and there is temperature decrease. (eg. evaporation, photosynthesis)
Remember -> The new K-pop group 'EXO' they jump OUT, in their MVs, their fans are called EXOTICS :)

To measure the energy output of fuels, you used the equation: Heat energy = mass of water (in grams or that) x c (the energy transformed - the specific heat capacity of water, which is always 4 [SHC]) x the change in T
Then to find the energy transformed do Heat energy/mass of fuel used.

[It was from the experiment you did in class. I'm not sure if we really need it though.]

COMBUSTION-
Any burning reaction is called a combustion reaction.
Fuel + oxygen -> carbon dioxide + water
[That's the equation for combustion.]
Remember -> I don't know, I just do (remember, I meant) ...but maybe F oh, see water? --" I don't know.

Incomplete Combustion-
In the absence of an adequate supply of oxygen, fuels may react to form carbon monoxide and water, this is incomplete combustion. Carbon monoxide is highly poisonous, soot is the product of incomplete combustion.
(eg. Methane + oxygen -> water + carbon monoxide)

FERMENTATION-
We can produce beer and wine by using the ANAEROBIC respiration of yeast. This means that the yeast is respiring without oxygen. [Which is when anything respires anaerobically, it is respiring without oxygen.] This process is known as fermentation and we produce alcohol by doing so.

Yeast turns sugar into alcohol
Sugar -> alcohol + carbon dioxide

Fermentation of glucose - the conditions required is 25-35 degrees Celsius and yeast works best at these temperatures.

Process-
As starch breaks doen into glucose, yeast - a single-celled fungus - absorbs the sugar and the bi-products are alcohol and carbon dioxide. For the yeast to work or be active, you need water - which all living things need - and it is the same as making bread. We don't get drunk by eating bread, LOL, because the alcohol evaporates in the oven. The yeast produces an enzyme which created the alcohol.

DENATURED <Remember this word, extra marks for scientific words :)
Basically, it' when the lock and key the which is the enzyme and the substrate which the enzyme will break down does not fit, maybe due to heating of the enzyme or whatever, but this causes the two to no 'fit' like a lock and key so a chemical reaction - in which enzymes break down the substrate can not occur!! We call the enzyme being denature if that happens.
Remember -> If that was like real life, it'd be bad, cuz then the heat of Thailand would change the shape of your house key and you won't be able to get into your own house!!

RATES OF REACTION-
Anything that increases the chances of collision of the two (whatever you are reacting), increases the rate or speed of reaction.
This could be:
-Increased surface area - when you cut large pieces up.
-Increased concentration. - if it's more concentrated, it just means the particles are more crowded - like in a subway, so there's more chance for you to 'bump' :D
-Increased temperature. - they move faster, and vibrate more :D try standing in the frying pan, you'd be jumping about -.-"
-Use of a catalyst.

CATALYST - A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.