Many students complain that they do not understand the chemistry and consider it one of the most difficult school subjects.For example, one phrase "heterogeneous reaction" suggest many students panic.In some ways they are no doubt right.Yet with chemistry can and should be friends.It surrounds our lives everywhere.Most good advice for students who are determined to make friends with this difficult science - a teacher to teach a given material for each lesson.To prepare for classes not on the principle: "I will not ask now - then you can not teach!", But on the principle: "I want everyone to know and understand, so will learn even what I did not ask!".Only with such an approach to business chemistry becomes an open book for you.And you will understand and notice it in all aspects of our lives.
In this article we will focus only on this chemical concepts as heterogeneous reactions.How to understand this term?If the word reaction is more or less clear (it refers to the interaction of substances), here with the word "heterogeneous" - many students have problems.Here we must recall the translation of the Greek word "geteros" - so different, diverse.
Heterogeneous reactions: examples from the life of
heterogeneous reactions take place between the different in nature, but rather the physical state of the substance.Another of the primary school each student knows that any material can be in three states of aggregation (or 3 phase) as a solid, liquid or gaseous state.So, it is considered a heterogeneous reaction if the substance entering into it, are in different states of aggregation, for example:
- gas + liquid,
- gas + solid,
- liquid + solid.
If substances react with each other are in the same state of aggregation, such reactions are called homogeneous.The word can also be translated from the Greek, "gomos" - the same, similar.
Homogeneous and heterogeneous reactions commonly occur in our lives.Consider, for example, reaction of burning firewood.Firewood - is, by and large, organic chemical - cellulose.Without a doubt, the wood - a substance that is in a solid state.They burn through the action of oxygen.Oxygen - a gas.As a result, the combustion reaction is formed of wood charcoal, carbon dioxide and water.Combustion of wood as burning alcohol - a heterogeneous reaction.Examples can lead to infinity.
1) Rusting iron.Firstly, a chemical reaction, because the result of the new substance is formed of iron - rust iron hydroxide (III).Secondly, it is a heterogeneous process, since the iron - the solid and the water and oxygen in the air, which occurs under the influence of corrosion - it is a liquid and gas respectively.This process can be written using the following reaction equation:
Fe (tv.) + H2O (g.) + O2 (g) = Fe (OH) 3 (TV.)
2) quenching soda and vinegar.Many moms use this chemical reaction for the preparation of a lush test.When this is taken soda solid NaHCO3 in powder form and a 3% solution of acetic acid CH3COOH, therefore, it is also a heterogeneous process, since two interacting substances in different states of aggregation.This process is described by the equation:
NaHCO3 + CH3COOH = CH3COONa + H2O + CO2
Please note that the reaction products here are in different aggregate states - sodium acetate CH3COONa and water + H2O - is fluid and CO2 -is carbon dioxide.
3) Blackening of bronze monuments or silverware under the influence of environmental conditions - is also heterogeneous reactions.
Hopefully now this term does not cause you any trouble.And if you still have questions, do not be lazy to open a textbook on chemistry for class 8 and repeat the material covered again.It never hurts, because not for nothing that the Russian proverb says: "Repetition - the mother of learning!"
