Heterogeneous reactions are simple and understandable!

Many school children complain that they do not understand chemistry and consider it to be one of the most difficult school subjects. For example, one phrase "heterogeneous reactions" leads to panic terror for many students. In some ways they are without a doubt right. But still you can and should be friends with chemistry. It surrounds our life everywhere. The best advice for students who have firmly decided to make friends with this difficult science is to teach the material assigned by the teacher for each lesson. Prepare for classes not according to the principle: "I will not be asked today - that means I can not teach!", But according to the principle: "I want to know everything and understand, therefore I will learn even what they will not ask me!". Only with this approach to the subject chemistry will become for you an open book. And you will begin to understand and notice it in all manifestations of our life.

In this article, we will focus only on a chemical concept, such as heterogeneous reactions. How to understand this term? If the word reaction is more or less clear (it denotes the interaction of substances), then with the word "heterogeneous" - many schoolchildren have problems. Here you need to remember the translation from the Greek word "hetros" - hence, different, unlike.

Heterogeneous reactions: examples from life

Heterogeneous reactions occur between different in nature, or rather the physical state of substances. From the elementary school, each student is aware that any substance can be in 3 aggregate states (or in 3 phases): solid, liquid or gaseous. So, the reaction is heterogeneous if the substances entering it are in different aggregate states, for example:

• Gas + liquid,
• Gas + solid,
• Liquid + solid.

If the substances reacting with each other are in the same aggregate state, then such reactions are called homogeneous. The word can also be translated from Greek: "homos" - the same, similar.

Homogeneous and heterogeneous reactions are widely encountered in our lives. Consider, for example, the burning reaction of firewood. Firewood is, by and large, a chemical substance of organic origin - cellulose. No doubt, wood is a substance that is in a solid aggregate state. They burn due to the action of oxygen. Oxygen is gas. As a result of the reaction of burning wood, coal, carbon dioxide and water are formed. Burning wood, as well as burning alcohol - a heterogeneous reaction. Examples can be brought to infinity.

1) Rusting of iron. Firstly, it is a chemical reaction, because as a result, a new substance is formed from iron-rust is ferric hydroxide (III). Secondly, it is a heterogeneous process, since iron is a solid substance, and the water and oxygen of the air, under the influence of which rust is produced, is a liquid and a gas, respectively. This process can be written using the following reaction equation :

Fe (solid) + H2O (x.) + O2 (g) = Fe (OH) 3 (s)

2) Quenching of soda with vinegar. Many mothers use this chemical reaction to make a lavish dough. This takes solid NaHCO3 soda in powder form and a 3% solution of acetic acid CH3COOH, hence this is also a heterogeneous process, since two substances interacting in different aggregate states interact. This process is described by the equation:

NaHCO3 + CH3COOH = CH3COONa + H2O + CO2

Note that the reaction products here are in different aggregate states - sodium acetate CH3COONa and water + H2O are liquids, and CO2 is carbon dioxide.

3) Blackening of bronze monuments or articles made of silver under the influence of environmental conditions are also heterogeneous reactions.

I hope that now this term does not cause you any difficulties. And if you still have questions, do not be lazy to open a textbook on chemistry for grade 8 and repeat the material again. It never hurts, it's not for nothing that the Russian proverb says: "Repeat is the mother of learning!"