Chemical reaction equation, historical question

In summary, the equality sign was abandoned in 1884 because chemical reaction equations are not mathematical equations and there is no equality in the equation in mathematical sense.
  • #1
7777777
27
0
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.
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been replaced by something else?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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  • #2
An arrow indicates direction, whereas an equality sign does not.
 
  • #3
As long as a reaction is not in equilibrium, the reaction proceeds in one or the other direction. Hence it is more convenient to use arrows. In some situations, it is also necessary to distinguish formally between reactands and products, e.g. in calculating the potential of a electrochemical half cell, you divide by convention the product of the concentration of the products by that of the reactands.
 
  • #4
Ok, there is a direction in chemical equation, reactants are cause and products are effect,
hence there is causality. But not in mathematical equation, there is symmetry in mathematical
equation instead of causality. 1+1→2 does not make sense because 2 is not caused by 1+1,
instead there is symmetry: 1+1=2 and 2=1+1.

Perhaps this is a weakness of mathematics, it does not seem offer causality.
 
  • #5
7777777 said:
Perhaps this is a weakness of mathematics, it does not seem offer causality.
You gave the answer to your question yourself.
7777777 said:
1+1→2 does not make sense
And there are instances where mathematics offers a cause and effect.
http://www.math.niu.edu/~richard/Math101/implies.pdf
Mathematical Induction
Contraposition
Contradiction
 
  • #6
I found this.

chemistry and symbols
http://www.chemistryviews.org/details/ezine/2746271/History_and_Usage_of_Arrows_in_Chemistry.html

1789 Lavoisier uses "=" sign for a chemical equation.
1884 Vant Hoff uses double arrows
1901 single arrow to designate direction, products and reactants
http://www.chemistryviews.org/SpringboardWebApp/userfiles/chem/image/2012/2012_November/Arrow [Broken]

http://www.chemistryviews.org/SpringboardWebApp/userfiles/chem/image/2012/2012_November/Arrow [Broken]

Other uses of arrows in chemistry shown, past and present.
 
Last edited by a moderator:
  • #7
Nice links. This timeline was very interesting→
Arrow_Timeline6.gif
 

1. What is a chemical reaction equation?

A chemical reaction equation is a representation of a chemical reaction using chemical formulas and symbols. It shows the reactants on the left side and the products on the right side, with an arrow in between to indicate the direction of the reaction. It also includes coefficients to show the relative amounts of each substance involved.

2. How do I balance a chemical reaction equation?

To balance a chemical reaction equation, you must ensure that the number of atoms of each element is the same on both sides of the equation. This is done by adjusting the coefficients of the reactants and products. Start by balancing elements that appear only once on each side, then move on to more complex elements. Finally, check that all elements are balanced and that the overall charge is also balanced.

3. Why is balancing a chemical reaction equation important?

Balancing a chemical reaction equation is important because it follows the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. By balancing the equation, we ensure that the same number of atoms of each element are present before and after the reaction, and that no matter is lost or gained.

4. Who first developed the concept of chemical reaction equations?

The concept of chemical reaction equations was first developed by Antoine Lavoisier, a French chemist, in the late 18th century. He is known as the "father of modern chemistry" and his work on chemical reactions led to the development of the law of conservation of mass.

5. How have chemical reaction equations evolved over time?

Chemical reaction equations have evolved significantly over time, from simple representations of reactions using words and symbols, to more complex equations that accurately depict the amounts of substances involved. The use of computers and advanced mathematical models has also allowed for more precise and detailed equations. Additionally, new chemical reactions and compounds are constantly being discovered, leading to further developments in chemical reaction equations.

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