Lesson 1: How to Write an Excellent Lab Report Introduction Part

The bold step you have taken is to join this free course. You are in the right direction of perfecting your chemistry lab report writing. I believe you have already known what you will expect from this course. For that reason, I will discuss briefly the importance and parts of a good chemistry lab report before I embark on our main theme for this lesson (how to write an introduction part of chemistry lab report). If you do not know, then do not worry! You can access the previous post here, Free Course: How to Write an Excellent Chemistry Lab Report for Undergraduate Students. 

A lab report contributes to a percentage of your final marks. In some institutions, it contributes to 10%, 15%, and 20%. Furthermore, lab experiments aid in subject concept understanding. Therefore, writing a good chemistry lab report will enable you to get high grades in your final chemistry exams.

Surprisingly, the majority of students does not write a chemistry lab report as required. A chemistry lab report always contains an introductory part, an experimental procedure section, a discussion part, a conclusion section and a reference part. Though, some institutions require students to include an abstract part. In this case, the abstract will come before the introduction part. 

An introductory part is where you introduce readers to your lab report. Hence, it must be interesting! In the introduction, you have to talk about the theoretical background of your lab report title. You have to prove to readers that you understand your topic. 

You should properly in-text cite your introduction part, according to the instructions provided. So, you may be required to write a lab report based on a particular Academic Referencing Styles such as MLA, APA, Chicago, and Harvard and so on. For you to score high marks, you have to adhere to Academic Referencing Styles given. 

The last paragraph of your chemistry lab report should often consist of your thesis statement. Though, some students place their thesis statement anywhere in the introductory part. However, I prefer it to be in your last paragraph of the introduction. 

What is a thesis statement? A thesis statement states your stand in your lab report. In other words, it tells readers what your lab report entails (objectives of your lab report). If your lab report is about the factors that affect the rate of reaction, inform readers about this. You can write a thesis statement as follows: 

• In this experiment, temperature as a factor affecting the rate of reaction was investigated.
• This experiment aims at investigating temperature as a factor affecting the rate of reaction. 

In some lab reports with an abstract, you can omit objectives in the introductory part, but include it in the abstract part. It will still make sense. In such situations, in the introductory part, you will just talk about the theoretical background of your experiment.  

Example:

Lab Report Title: UV-VIS Spectroscopy 

Introduction:

UV-VIS spectroscopy is commonly used in analytical chemistry for quantitative analysis of various analytes. It can be used for analysis of transitional metal ions, biological macromolecules, and conjugated organic substances. UV-VIS spectroscopic analysis is usually conducted in solutions or sometimes it is performed in gases and solids (Bayerbach, 48). The principle of UV-VIS spectroscopy depends on pi-electrons and non-bonding electrons of molecules. These electrons are capable of absorbing visible light or ultraviolet energy, and in the process, they excited to higher energy levels (anti-bonding molecular orbitals) (Fausnaugh, 42). The excitation of electrons is inversely correlated to the wavelength of light that electron can absorb; for instance, electrons which are easily excited absorb longer wavelengths of light and the vice versa is true. 

When a light (incident light (I₀)) passes through a material, it is absorbed by the material. The light that emerges from the material after absorption of the incident (transmitted light (I_t), is always less than the incident light (I₀).  This decrease in light intensity is related to the concentration of the material, the particular absorption coefficient (alpha) of the material at specific wavelengths, and the thickness (d) of the material that light passes through (Mecozzi and Marco, 22420). The transmittance of the absorption is expressed in percentage and it is the ratio of transmitted light and incident light (I_t/ I₀). The ratio (I_t/ I₀) is applied in the determination of the absorbance (A) as follows:

A=-log (I_t/ I₀)

Additionally, the absorbance is also determined by using the Beer-Lambert’s law. According to Beer-Lambert’s law, the absorbance is directly related to the concentration(c) of the material (Fausnaugh, 41). Furthermore, it is proportional to the length (d) of the light path. Therefore, the Beer-Lambert law equation is as follows:

A=s X d X c

Where A denotes the absorbance, s represents the absorption coefficient. d signifies the length of the light path while c is the concentration of experimental material.

This experiment aims at using UV-VIS spectroscopy in the preparation of the standard curve, and determination of the concentration of the unknown solution. 

In this example, MLA Academic Referencing Style was used. As I explained earlier, you can see the thesis statement (objectives of the experiment) in the last paragraph. The remaining paragraphs focused on the theoretical background of UV-VIS spectroscopy. 

Final Remarks:

A chemistry Lab report consists of theoretical background and thesis statement. Additionally, you have to write your chemistry lab report according to the instructions given. In the example, MLA Academic Referencing Style was applied. Moreover, references in in-text citation will be listed in the reference part. It will come later. 

If you have any question about this lesson, please kindly comment and I will address it. Or you can reach us through the email provided at top of the page.