Chem HL IA 21/25

Research Question: What is the effect of the different temperatures (10,20,30,40,50,60°C) of hydrogen peroxide on the oxidation of tea stain on an egg shell by measuring the absorbance of the solution using a colorimeter?

Topic: Redox reactions

[본문내용]

Investigating the extent of tea stain removal at different temperatures of hydrogen peroxide

Research Question: What is the effect of the different temperatures (10,20,30,40,50,60°C) of hydrogen peroxide on the oxidation of tea stain on an egg shell by measuring the absorbance of the solution using a colorimeter?

Introduction:

Tea leaves are widely known for causing teeth stains. They are composed of various different compounds, but the main compounds are called polyphenols also known as tannins. Tannins are astringent thus aid the binding of chromogens which is a compound that contains a chromophore, an unsaturated group responsible for absorbing radiation.  As these pigment molecules absorb visible light, electrons become excited and they absorb certain wavelengths of light energy. As a result, the complementary colour is visible which is the colour of the teeth stain.

There are two types of stains: extrinsic and intrinsic (Alqahtani, 2014). Extrinsic stains occur on the surface of the tooth usually due to the accumulation of chromogenic substances. On the other hand, intrinsic stains are usually discolourations that occur deeper into the tooth, usually a result of ageing. In this investigation, tea stains were explored, which is an example of an extrinsic stain as tannins gets absorbed into the enamel of the tooth, causing the chromogens to bind, and therefore leads to discolouration…

• 총 페이지수: 12 pages
• 과목: Chemistry
• 주제: Investigating the extent of tea stain removal at different temperatures of hydrogen peroxide
• The file is in Word format.