Chemical Reaction: When the atoms of one substance, are changed and made into a new substanceThe chemical reactions we learned in chemistry are; synthesis, decomposition, combustion, single replacement, double replacement, and acid/base.Synthesis: A reaction which simple reactants form a compound product. While the product will always be a compound, the reactants can be either elements or compounds. If one is trying to identify this reaction, look at the product. If all the reactions come together one product. Synthesis has occurred. The equation for this reaction looks like: A + B = AB. For example The synthesis of water is 2H2 + O2 ? 2H2O. An experiment that is an example of synthesis is the reaction between Zinc(s), and Iodine(aq). When water is added to this, a reaction occurs and a purple smoke is emitted. The equation would look like Zn(s) + I2(aq) ? ZnI2. This is synthesis because Zinc and Iodine, two elements formed one compound. One can see synthesis occurring through the purple smoke.Decomposition: Opposite of a synthesis reaction, in a decomposition reaction, a chemical bond is broken and a compound will break down into simple compounds, or elements. This reaction looks like AB ? A+B. A real life example of this is seen through “splitting” water. This is done when electricity reacts with 2H2O and breaks down the compound forming 2H2 and O2. A Black Snake experiment was done in class as an example of decomposition. In this experiment, powdered sugar and baking soda were mixed and slowly added into a sand pile crater with alcohol around the rim of the crater. When fire was added to the rim, a “black snake” formed. The reactions that took place in this lab were C2H5OH (alcohol)+ O2 ? 2CO2 + 3H2O. The chemical bond that formed alcohol, was broken down to create carbon dioxide and water. 2NaHCO3 (baking soda) ? NaCO3 +H2O + CO2. In this experiment, baking soda was broken down and formed; sodium percarbonate, water, and carbon dioxide. Lastly, C12H22O11(powdered sugar) ? CO2 + 11H2O + 11C. Powdered sugar decomposed and created carbon dioxide, water, and carbon alone. Combustion: According to Thought Co. , “A combustion reaction is a type of chemical reaction where a compound and an oxidant is reacted to produce heat and a new product” (Helmenstine, 2017). In a combustion reaction, a compound that has hydrogen, carbon, and sometimes oxygen is combined with oxygen, creating products of carbon dioxide and water. In these reactions, light and or heat are produced. There are a lot of real life examples, but a simple one is lighting a match. This equation can be expressed as CxHy (Oz) + O2 ? CO2 + H2O. This reaction can also be seen in the decombustion lab because although, the reactants broken down into simple compounds the compounds that were produced were mainly water and carbon dioxide. Another experiment for combustion is an ethanol experiment. By placing ethanol into a large bottle and mixing it, a vapor is made. Then lighting a stick or a match on fire and placing it in the bottle, a flame is produced (heat and light). The formula would look like C2H5OH + 3O2 ? 2 CO2 + 3 H2O. Single Replacement: In a single replacement reaction, the atoms of one or more elements replace the atoms of another element in a compound. The equation for this reaction is A+BC ? AC + B. One can determine if a single replacement will occur by looking at the activities series list. More reactive elements will replace lesser reactive elements. A real life example of a single replacement reaction occuring is when galvanized steel rusts. Which looks like Fe2 + 2 H2O ? Fe(OH)2 + 2 H. An experiment that is an example of single replacement is the reaction between Zinc and Hydrochloric Acid. When small pieces of zinc are placed into a balloon, and a beaker has about 50 mL of hydrochloric acid in it, and the balloon is place of the beaker and the zinc pieces fall into the hydrochloric acid, the gas emitted inflates the balloon after a couple of minutes. This is a single replace reaction because, Zn + HCL will produce H + ZnCl due to the fact that Zn is more reactive than H. Double Replacement: In this reaction, an exchange of ions between compounds occur. Written, a double replacement looks like Ax + By ? Ay + Bx. These reactions will usually form a precipitate or a thick substance. This is because two aqueous compounds produce and aqueous and a solid. To identify a double replacement, one can see if the cations are switched. An example of a double replacement reaction is when an antacid neutralizes stomach acid. Ca(OH)?2 + 2 HCl? CaCl 2 + 2 H2O. In class an experiment was done to simulate this reaction. Solutions were mixed together and students would record the reactions. One of the reactions, Sodium Carbonate and Calcium Chloride, which were both clear liquids produced a white thick substance. Na2CO3(aq) + CaCl2 (aq) ? 2NaCl (aq) + CaCO3 (s) is what the equation for this reaction looks like. One can see that the Na and the Cl are switched to produce a precipitate which is why the thick white substance is produced. Acid/Base: Acids are substances that release positive Hydrogen ions in a solution, while bases accept those hydrogen ions. Some acids that one comes in contact with on a regular basis are; stomach acid (HCl), vinegar/ acetic acid (HC2H3O2), and soda or carbonic acid (H2CO3). These acids can have a sour taste, conduct electricity and deteriorate some materials. That is because the acids have a pH less than 7. Most acids have a hydrogen in their formulas. Bases that one uses are soaps and or sodium hydroxide (NaOH), antacids/ magnesium hydroxide (Mg (OH)2) etc. Bases usually have hydroxide in the substance and the it will be a negative ion. Bases have a higher pH level than acids making them slippery, and bitter tasting. In a neutralization reaction, acids and bases combine to produce water and salt.