How is it that moles are not necessarily conserved in a chemical reaction?

Question

"Mass and atoms are conserved in every chemical reaction, but moles will not necessarily be conserved.”

What do they mean by that?

Answer 1

This means that sometimes the stoichiometry of a reaction will cause the number of moles in a product to differ from the number of moles of the reactants.

An example would be 2 moles of benzaldehyde reacting with an acid catalyst to give you one mole of benzoin, which is a compound each molecule of which consists of two molecules of benzaldehyde.

An easier example to think of, perhaps, would be formation of nitrogen dioxide (NO2), as a result of nitric oxide reacting with oxygen. The balanced equation is like this:

2NO + O2 ----> 2NO2

So, two moles of NO react with one mole of O2 to give you two moles of NO2. Your reactants had 3 moles total, and your product has only 2 moles. All the atoms are there and nothing disappeared, but because of how NO2 is structured, your moles are not the same.

Answer 2

Remove Your Moles, Warts & Skin Tags in 3 Days
Easily, Naturally And Without Surgery

Answer 3

Moles essentially means number of particles. For example, if you have a pile of twenty pieces of clay, and you squeeze them into five bigger pieces of clay, you have the same mass you started with, but fewer particles. A chemical example might be like this:

2H2 + O2 = 2H2O

You started with three moles total on the left side (two of H2 and one of O2), which turned into two moles of water (H2O) on the right. If you count the atoms, you'll notice you have equivalent amounts of hydrogen and oxygen on each side, but you have fewer total particles.

Answer 4

Moles are in uncomplicated terms a fashion of counting atoms. while 12 eggs are mixed right into a great omelet, are dozen's conserved? Mass on the different hand, is the way that we degree the quantity of rely, and in a chemical technique, the quantity of rely can't replace - each and every atom must be accounted for.

Answer 5

one chemical can react with another to form a new substance. 2 moles of hydrogen reacts with 1 mole of oxygen to form 2 moles of water. Or more simply I part of orange syrup added to 4 parts of water to make 1 drink.

Answer 6

For example:
2(H2) + (O2) -> 2(H20)

So all the matter is conserved, but there are three moles on the left side (two of hydrogen ane one of oxygen) and two moles on the right side (of water).

Answer 7

a "mole" is just Avogadro's number of atoms of whatever

if it gets used 2 to one, then maybe half a mole left, no it should be a mole then too now that I think about it

Answer 8

Moles are a "count" of the number of particles. If you take one particle (atom) of sodium and bond it to one particle (atom) of chlorine {that's two particles, total), you produce only one particle of sodium chloride. So, two particles have glued themselves together to make one unit. All of the mass of the individual particles is contained in the mass of the new compound, so mass is conserved.

Answer 9

it means that you may start with a certain number of moles of reactants but end with a different number of moles of products. For example.

2Na + Cl2 --> 2NaCl

you start with 3 moles of reactants (2mol Na, 1 mol Cl2) but end with only 2 moles of product, NaCl.

Answer 10

This is an interesting question, and one that has been the source of confusion for me for a very long time.