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A chemical equation is a way of expressing a chemical reaction in a quick, symbolic manner. Like maths equations, there are symbols that represent the reactants and products involved in the reaction. These mathematical-chemical representations are important for scientists because they use them to communicate about their experiments and required materials, allowing them to plan those experiments better.
Scientists can also use these equations to predict the outcome of different reactions, which helps them develop new materials by choosing the right reactants. They may also want to know how much of each reactant they’ll need in order to get a certain amount of product, so they’ll use these equations for calculations as well.
Most people remember chemical equations as a rather tedious part of a high school or college curriculum. But in the real world, chemical reactions lay the very basis of our industrial and digital societies. Without chemical reactions, we would have no computers or life-saving medication.
Of course, mastering chemical equations on the theoretical front is quite a task, and if you’re struggling, there are several online resources to help you with your journey through the exciting world of chemistry; Sweetstudy’s chemistry homework help, for example. Today, however, we’re looking at five chemical reactions that have made modern life possible.
The Haber Process, Also Called Haber-Bosch
The Haber process, also called Haber-Bosch, is a method of producing ammonia from hydrogen and nitrogen gases. It relies on a metal catalyst that lowers the reaction temperature and results in a high yield of ammonia. The process was first discovered by Fritz Haber in 1908, but it wasn’t until 1913 that Carl Bosch was able to make it efficient enough for industrial use.
Ammonia is then used to create fertilizer, which increases the yields of food crops and improves the nutrition of fruits and vegetables. It’s also used in many other products such as explosives, plastics, dyes, and cleaning substances.
While production from nitrogen gas makes the cost low, there are some disadvantages to this manufacturing process. There is a large amount of energy needed (as much as 25% of the world’s natural gas supply), so many companies are exploring alternative methods for creating fixed nitrogen more efficiently.
The refining processes involved also emit harmful gases like hydrogen cyanide into the atmosphere due to inefficient control technologies and poor pollution management techniques at plants all over the world.
The Chlor Alkali Process
In the Chlor-alkali process, an electrolyzer powered by a DC current is used to split water molecules into their constituent elements. Brine comes into contact with the cathode, which gives up its sodium ions to become hydrogen gas. The anode then combines with the chlorine ions in the solution to create chlorine gas.
The net effect of this process is that it produces one molecule of sodium hydroxide (NaOH) and one molecule of hydrochloric acid (HCl). Sodium hydroxide, or lye, has many industrial uses but is most commonly used in paper production and as a drain cleaner. Hydrochloric acid also has a wide variety of uses—including cleaning metals and processing foods like sugar and gelatin—but is most often found in gastric acid, where it aids digestion by breaking down protein bonds in food.
Carl Wilhelm Scheele first came up with this chemical reaction in 1785 but didn’t publish his findings until 1787; Humphry Davy discovered that calcium could be similarly prepared from lime water three years later. The Chlor-alkali process was first patented by Swedish chemist Carl Wilhelm Scheele (1742-1786), who invented several other key chemical processes during his lifetime, including the production of oxygen using manganese dioxide as a catalyst and identifying ammonia’s presence in atmospheric nitrogen through his discovery of ammonium chloride.
The Ostwald Process
As you’ll remember from our earlier discussion of ammonia, it is the nitrogen-containing compound fundamental to many important fertilizer products. It may come as a surprise to learn that these fertilizers—which help feed billions of people around the world—all begin with a substance most would consider poisonous: nitric acid.
While ammonia and nitric acid are both colorless liquids at room temperature, they are highly reactive with one another. This chemical reaction produces more nitrogen in the form of nitrate and nitrate compounds, which can be absorbed by plants (like those growing in your garden) and turn into proteins.
Through this process, nitrogen compounds present in the air were harnessed by humans for the first time, leading to significant increases in agricultural production around the world. The Ostwald process also produces nitrous oxide: better known as laughing gas.
Cyanide Extraction of Gold
While you might not be a fan of this chemical compound, its useful properties made it a key component in the extraction of gold throughout much of the 1900s. The compound is generally found as either a colorless gas or crystalline solid and can be highly toxic—which is why it’s used to extract gold from ore.
According to the EPA, cyanide gas can affect the cardiovascular system, and exposure can even lead to death. It’s for this reason that it has historically been used for executions by lethal injection. Some people also use cyanide compounds as insecticides or pesticides.
However, when combined with potassium hydroxide and heated up in the presence of air, it produces hydrogen cyanide and sodium carbonate. This reaction was discovered by William Hyde Wollaston in 1824 and was later improved upon by Johann Wilhelm Geitner sometime between 1825 and 1832.
The general reaction seems to go like this: NaCN + 2 KOH → 2 KCN + NaOH; then 2KCN + 3NaOH → 2KCNO + 3H2O + K2CO3 (NaCN being sodium cyanide, KOH being potassium hydroxide).
This means that while you’re extracting your metals through this process, you’re also producing relatively harmless salt crystals such as sodium carbonate—which are very useful in all sorts of other industrial processes!
Nitric Acid and Ammonia Synthesis
The Ostwald process, named for German chemist Wilhelm Ostwald (1853-1932), is the production of nitric acid from ammonia. The Ostwald process is a series of steps as illustrated below:
- Catalytic oxidation of ammonia to produce nitric oxide
- Catalytic oxidation of nitric oxide to produce nitrogen dioxide
- Absorption and condensation of the nitrogen dioxide with water to form nitrous and nitric acids, which are then separated by distillation
- The reaction between the purified nitric acid and more ammonia in an ebullated bed reactor creates ammonium nitrate, which is then separated via evaporation.
Nitrogen oxides are very important in our daily lives because they can be used in a variety of chemical reactions to synthesize other compounds that we use every day. For example, when this product is reacted with methanol, we get methyl nitrate/nitromethane, which can be used as a propellant or fuel additive in racing cars and model rockets.
When it’s reacted with hydrogen peroxide, we get peroxynitrite (ONOO⁻), a free radical that causes vasodilation (a widening of blood vessels) when inhaled by asthma patients, thereby reducing asthma symptoms during an attack.
Some of the most remarkable advances in the history of chemistry have started with chemical reactions. At the heart of the industrial revolution and the mass industrialization that followed, chemical reactions were at the forefront of bringing humanity to the modern age.
Although these equations can be rather confusing at times, especially when it comes to balancing equations, they do build up the rubric of the world we live in. Whether they are industrially deployed or simply the transformation of carbon dioxide into oxygen by trees, chemical reactions make the world go round.