## balancing reaction law

D-nice1D
Posts: 19
Joined: Fri Sep 28, 2018 12:21 am

### balancing reaction law

It appears that balancing the chemical equation Cu + SO2 S CuO + S would be simple if we could just add another O atom to the product side:
Cu + SO2 S CuO + S + O. (a) Why is that balancing procedure not allowed? (b) Balance the equation correctly.

I'm not sure what the actual correct answer to A is.

Chem_Mod
Posts: 18716
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 631 times

### Re: balancing reaction law

You cannot add new reactants or products to a chemical equation. You can only change the ratio of what substances are there, using stoichiometric coefficients to balance the number of atoms.

Haorui Li 1A
Posts: 30
Joined: Mon Jun 17, 2019 7:23 am

### Re: balancing reaction law

You cannot add a product to the chemical equation because a chemical equation describes a chemical reaction, it is an expression that gives the identities and quantities of the substances involved in a reaction, if the product was not there originally, you cannot add one. Balancing chemical equation only involves changes in coefficients before each compound, so you need to calculate.

Julianna Laurentano 4G
Posts: 52
Joined: Wed Sep 18, 2019 12:21 am

### Re: balancing reaction law

As stated above, you cannot add reactants or products to the chemical equation, as the total mass before must equal the total mass after. However, you may use coefficients to make sure each side of the reaction is balanced in respect to the atoms of each element.

PGao_1B
Posts: 50
Joined: Sat Jul 20, 2019 12:15 am

### Re: balancing reaction law

In chemical reactions atoms are not created or destroyed. Total mass before = total mass after. The law of conservation of mass states that the total atoms of reactants = the total atoms of products, so you cannot add reactants or products to a chemical equation.