Honors Chem 10 February 18th, 2015
In this lab, one will determine which chemical reactions match up with the five possible types of reactions. In order to accomplish this, one will need to know the different signs that tell if a chemical reaction has been made. These visual clues include change of heat, formation of a gas, change in color, and the substance precipitating.
The changing of heat means that the substance drastically changed colder or warmer.
The formation of a gas means that the substance changed to a gaseous state when coming into contact with another element. Change in color means that upon combining the two elements in the reaction, the substance therefore changed color. If the substance precipitated, it means that the solid compound formed into an aqueous state upon combining the substances together. In order to write a chemical equation, one must understand what a chemical equation is first. A chemical equation is a symbolic representation of chemical and physical processes that use notation to communicate information. Equations follow the formula of
Reactants → Products
, where the arrow indicates a change in the equation. The first thing one should do when writing a chemical equation is to write a description of the reaction that occurred, including the physical states of the substances.
Then, identify the reactants and products with their states of matter alongside of them.
Next, each substance is identified by it’s correct chemical formula. Lastly, the reaction equation must be properly balanced so that the atoms of each substances are equally balanced on each side. This will follow the conservation of atoms rule. To understand this experiment, one needs to know of all five types of reactions.
The five types of reactions are Combination reactions, Decomposition reactions,
Singlereplacement reactions, Doublereplacement reactions, and Combustion reactions. A Combination reaction is a reaction where two or more elements or compounds combine together to form a single compound. Combination reactions are usually considered exothermic, because when bonds form between the reactants, heat is then released. Rusting is also another example of combination reaction. If two elements or compounds come into contact and form rust, it is considered combination.
A Decomposition reaction is the separate of a chemical compound into elements or simpler compounds, the exact opposite of a Combination reaction. It is considered to be an undesired chemical reaction because of its limited ability to stay stabilized in heat, radiation or humidity. Thermal decomposition reactions are when the substances breaks into two or more substances upon heating up. This type is usually considered endothermic because it requires heat instead of producing it. Electrolytic decomposition reactions happen when an electric current passes through an aqueous solution of a compound. Lastly, Photo decomposition is a chemical reaction where a substance is broken up into simpler substances by being exposed to light. A Singlereplacement reaction is a type of oxidationreduction reaction when an element or ion moves out of one compound and into another. This is usually represented by A + BC → B + AC . For this to happen, the two substances that switched place must be either different metals or halogens. The metals with the highest propensity are listed first, and the more unreactive metals are listed last. A metal higher on the list will be able to displace anything below it, and same goes for halogens with high propensity. A Doublereplacement reaction is a chemical process involving the exchange of bonds between two reacting chemical species. This is usually represented by AB + CD
→ AD + CB . THe bond produced between the reacting species can be either ionic or covalent. This reaction usually results in