2009 30 July Chemistry Chemical Changes Post TWO Sorry to say, this post will be EXTREMELY SHORT! >.< I'm really sorry. For the next two post, will be just a brief demostration on the different chemical reactions.
Okay, let's start. What can we understand from the term Synthesis? No, it is not photosynthesis! It is Synthesis! Well, Synthesis is actually a form of reaction, whereby an element combines with another element to form a compound, or in other cases, an element and another compound combine to make a new compound. Or sometimes, two compounds combine together to create a new compound. Synthesis is also called combination, construction or composition reactions. Remember this, we can represent Synthesis with this simple equation. A + B -> AB A very common example would be burning hydrogen gas and oxygen gas to produce water, which also can be represented by the equation. 2 H2 + O2 -> 2 H2O Or, another example would be that sulfur trioxide reacts with water to make sulfuric acid. Or in this case, is... H2O + SO3 -> H2SO4 So what you would see in a 'test tube' would be that two substance combine to make one new substance. And that sums up Synthesis. Decomposition, in order words, is also called, desynthesis, decombination or deconstruction. As we can very obviously see from the word Desynthesis, we can actually that it opposite of Synthesis, hence, it is the separation of a compound into other elements and/or compounds. We can simply repesent it in this form. XZ -> X + Z Now, we will look at some examples of decomposition. If we heat a bicarbonate soda of water, it will release water, carbon and sodium carbonate. We can represent it with this equation. 6 NaHCO3 -> 3 Na2CO3 + 3 H2O + 3 CO2 Next, and lastly, I'll move on to combustion. Combustion, as the name suggest, is basically the burning of organic material. In order for combustion to happen, there must be oxygen, this is so as the material will react with the oxygen in the air around it to burn. We can simplify combustion, and write it in this form. Hydrocarbon + Oxygen -> Carbon Dioxide and Water To further demostrate combustion, if one candle if left out in the open to burn and the other is covered with a beaker, the one left out to burn will obviously burn longer than the one in the beaker as in the beaker, there is limited amount of oxygen for the 'fire to eat'. Here are some examples of combustion. CH4 + 2 O2 -> 2 H2O + CO2 The next one... 2 C2H6 + 7 O2 -> 6 H20 + 4 CO2 And with this, I have come to the end of this Chem Journal post. Link One Link Two Link Three Glossary Element Anyone of the substance in the periodic table. Compound A substance formed by a union of two or more elements or compound with a definite propotion by weight. Organic A class of chemical compound having a carbon basis. Hydrocarbon A organic compound that only contains hydrogen and carbon. |
By Zhan Peng from 2-6 Catholic High School Class 2-6 One Golden Rule NOTHING |