Examples of Chemical Changes in Everyday Life

A Chemical change or Chemical reaction occurs when two or more substances combine together to form new substance. Examples of chemical change in everyday life are studied in this article. 

Keywords: Chemical Reaction, Oxidation, Protein, Starch gelatinization, Denaturation.

Table of Contents

1. Introduction
2. Chemical changes in everyday life
3. Conclusion

1. Introduction

Hi friends, in this article we will learn about some chemical change or reactions which talks place in our surroundings. We all know that chemistry is everywhere, and we need to observe it carefully to understand basic science behind these events. It will altogether be learning and fun as well. In this article we will see common chemical changes in daily life. And we will discuss the chemistry behind these events.

2. Chemical changes in everyday life

2.1 Souring of Food

Souring is a food preparation procedure to make physical and chemical change. It is occurred due to addition or formation of acid compound in the food. For example; souring of milk is observed because it has Lactobacillus bacteria. They are also known as lactose fermenting bacteria which uses lactose sugar form the milk to produce lactic acid. This results in sour milk.

Figure 1: Souring of milk by Lactobacillus bacteria

2.2 Rising Bread

In the process of bread making; for fermentation purposes yeast is added in dough. The yeast is microorganism which transforms the sugar or glucose in the dough into carbon dioxide gas and ethanol. The formed gas is trapped in tiny pores of dough, as the amount of gas increases the dough also rises. The ethanol produced during fermentation evaporates during the bread baking process.

Figure 2: Rising bread

Figure 3: Fermentation process

2.3 Heat in Cooking cause chemical

The potatoes after boiling in water becomes soft. How this happens?

Figure 4: Boiled potatoes

The answer is that; starch is a major component of potatoes. When potatoes are boiled in water; it breaks down the intermolecular bonds of starch molecules also allows to incorporate water molecules into three dimensional structure of starch molecules. In this process granules of starch dissolves in water. This process is known as Starch gelatinization. This is permanent change in the chemical composition of potatoes and it becomes soft.

2.4 Hardening of egg

Figure 5: Boiled egg

An egg becomes hard after boiling in water.  This is also a chemical reaction which takes place when egg exposed to heat. Eggs are rich in protein which is made up of various amino acids. The protein molecules fold themselves to form three dimensional structures. When an egg is heated the protein molecules unfolds and forms strong bonds with other protein molecules. This phenomenon is called as denaturing the protein. Due to this change in structure of protein egg turn hard when exposed to heat.

2.5 Food browning

You must have seen any fruit of vegetable turns brown color when exposed to air and light. Why it happens?

Figure 6: Food browning

Figure 7: Enzymatic browning by oxidase enzymes

This process is known as enzymatic browning which involves chemical reaction of various enzymes such as oxidases with air oxygen and phenol compounds to form melanin. The melanin is class of natural pigments which generally appears as dark brown color. Therefore, if cut fruit kept longer time in contact with air, it slowly turns in to dark brown colored.

2.6 Copper vessels changes color

Figure 8: Copper vessels

Copper metal upon exposure to air oxygen or moisture, it forms copper oxide and copper hydroxide coating on metal surface. The copper oxide appears as black color whereas copper (II) hydroxide has green color. Hence the copper vessels become greenish when kept on contact with air and moisture.

Figure 9: Oxidation of copper

The greenish black coating on copper vessels can be removed by rubbing a lemon on metal surface. This is due to the reaction of citric acid present in the lemon and copper oxides to form copper citrate. 

Figure 10: Reaction of copper oxides with citric acid

The salt copper citrate is easily soluble in water hence it can be removed by washing the vessel with water.

3. Conclusion

Friends, in this article we have seen common chemical reactions in daily life.  These reactions we can observe by changes in nature or color of the substances.

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