Acetic acid molecule

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mfang4's picture
Submitted by mfang4 on Wed, 27/07/2016 - 21:18

There are millions of things that exist on Earth, all of which are formed by atoms which are basic building blocks of matter.Every atom contains its unique atomic composition as well as chemical and physical properties. They combine to form molecules and crystal lattices in the form of an element or compound. The different combination of microscopic atoms create different substances.

An element comprises multiple atoms of the same kind and cannot be broken down to a simpler type of matter by chemical or physical means, whereas a compound consists of two or more types of atom and is able to be simplified to elements by chemical means. The combination of different compounds or elements creates another new substance known as a mixture, which can be divided back to its simplest form by physical and chemical means. Molecules can range in size, from the single bond of two atoms to polymers and DNA. An example of a molecule that makes up a commonly used substance known as vinegar is acetic acid.

Acetic acid- what is it?

Acetic acid is a colourless liquid compound that makes up about 3-20% of vinegar, making it the main component of vinegar apart
from water. Its chemical formula consists of two carbon atoms, four hydrogen atoms and two oxygen atoms (CH3CO2H). The carbon atoms within the molecule comprise a balanced amount of protons, electrons and neutrons of 6. This causes the atom to have a stable structure. Oxygen atoms consists of 8 protons, electrons and neutrons, with electrons distributing around the 2 outer shells of the nucleus. In addition, hydrogen atoms only contain 1 proton and electron circling the nucleus. 
 
The chemical structure of acetic acid is displayed in the image below. As shown, each atom is bound together by covalent bonds, which hold the molecule together. Covalent bonds are strong chemical molecular bonds which involve the sharing of electron pairs between 
atoms. These bonds help to keep a stable balance of attractive and repulsive forces between atoms. In the diagram, the first carbon atom on the left hand side has a single bond with 3 hydrogen atoms as well as the second carbon atom. The second carbon has a double-bond with the oxygen atom and is singly bonded with the second oxygen atom. A single bond is also present between the second oxygen atom and the fourth hydrogen atom. 
 
Acetic acid contains distinctive characteristics and chemical and physical properties. Its pungent odour and sour taste attributes to the smell and taste of vinegar. Concentrated acetic acid is corrosive when it comes in contact with many types of metal. The melting point of acetic acid is between 16 to 17 °C and 118 to 119 °C for boiling point. It contains a molar mass of 60.05 g·mol−1 and a density of 1.0446 g/cu cm at 25 °C. Acetic acid is miscible with water meaning that all proportions of both substances can be mixed together homogeneously, enabling the dilution of the acid with water to produce vinegar. It also contains a low viscosity of 1.22 mPa·s at 25°C, attributing to vinegar's texture. Acetic acid is classified as a weak acid due to being unable to completely dissociate in a solution. This is when the molecule only releases some of its hydrogen atoms into the aqueous solution. It is also less capable at donating a hydrogen ion to a water molecule.
 

During the process of researching and building the 3D model, I encountered a few difficulties relating to the measurements of angles and finding the accurate ratio of the measurements between each bond. However, I later on solved these problems by calculating the approximate angle and ratio and consolidating it with my project partner. The biggest problem I had to face when building the model was learning how to program the 'turtle' to position the object in the accurate location. This was the hardest part as I was unfamiliar with the codes and their functions. However, it became a lot easier later on as many of the codes were repeated to produce a similar product. 

Furthermore, the investigation of the molecule was an interesting and beneficial experience for me as it helped me gain a lot more knowledge on not only acetic acid itself but molecules in general. I also discovered many interesting concepts and chemical processes that I never heard about before such as the process of dissociation. In the future, I will like to find out more about why the molecule is structured the way it is; what caused the distinct smell and taste of acetic acid; and what are some other functions and uses of the molecule. 
 
Below are a few useful and informative links that I have used in my blog:
 
 
Here are the programming for my model: 
 
 
Feel free to share your thoughts and answers to these questions in the comment section below.