I am reading a chemistry book printed in 1805. The chemical reaction equations are written using the equality symbol = instead of the arrow →, which is used in modern times.(adsbygoogle = window.adsbygoogle || []).push({});

Anyway sometimes it is still possible to see the "old fashioned" way:

http://www.jeron.je/anglia/learn/sec/science/changmat/page13.htm

Does anyone know why the equality symbol was abandoned, and when did it happen

in the history of chemistry? Are there reasons why this change was needed?

I know only a little about chemistry, I think this is a very basic question, but I cannot

seem to find the complete solution myself. I can think that maybe the = was replaced by → because chemical reaction equations are not mathematical equations, there is no equality

in the equation in mathematical sense.

If the chemical equations are not mathematics, then why the addition symbol + has not

been replaced by something else? The addition is a mathematical operation, so should

it be understood to mean also a chemical reaction? Something is added into something

else, perhaps this is an universal concept applicable not just in mathematics.

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# Chemical reaction equation, historical question

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