Balancing Atoms

[Claire_Sabol_2G]

Balancing chemical equations involves balancing the atoms of the products and reactants because atoms are neither created or destroyed in chemical reactions. If we look at mole numbers, however, these will often not be balanced between the two sides. Why is it that moles do not need to be balanced? Is this just due to the nature of the reaction (eg combustion)?

[Romi Moore 3k]

I'm not 100% sure, but I think it has to do with the fact that molar mass(g/mol) differs from element to element. If anyone else has more insight into that I'd be interested to hear too.

[Ally Mosher]

The stoichiometric numbers (moles) are balanced. This is because mass is neither created nor destroyed. You have to add the stoichiometric coefficients in order to balance the equation.

[505807269]

I think we don't have to worry about balancing the number of moles because usually that is based on experimental data. Balancing an equation with reactants and products is the basic theoretical step to obtain necessary information for that reaction for any given number of moles, or grams of reactants/products. We further calculate the number of moles given in the reaction using the molar mass of the elements and provided experimental data.

[Amanda Tran 1D]

Moles in a chemical reaction don't need to be balanced on both sides, in terms of how many total mols of reactants compared to products. Take the familiar chemical equation of 2H2 + O2 --> 2H2O for example. We have 3 moles on the left and 2 moles on the right. The law of conversation of mass is what tells us that mass can neither be created nor destroyed. And in our example, we have 2 molecules of H and 2 of O on both sides of the equation, which means the mass on both sides oof the equation are equal, following this law.

[Irene Kim 3E]

The ratio of moles of each element in an equation is usually fixed and given in the equation. For example, in the balanced chemical equation 2H₂ + O₂ = 2H₂O, the molar ratio of H₂ to water is 1:1, while the ratio of O₂ to water is 1:2. This fixed molar ratio is how we determine the empirical and molecular formulas for different reactions.

[Shreya Arcot 3K]

The moles of an equation don't need to be balanced, since we are focusing on conservation of mass. As long as there is an equal number of atoms of each kind on both sides, the mass is conserved. Thus, the equation is balanced.

Also, the molar ratio tells us information that allows us to find limiting reactants, how much product will be made, etc.

[Xiang Li 2F]

Moles of different sides might differ from each other due to the different composition of different molecules. I think we should care about the atoms other than being confused by the moles of molecules~