Reaction molar composition

• ch3m
In summary, the conversation discusses the molar composition of a reaction mixture in a paper involving crystal synthesis. The reported values do not seem to follow the convention of molar fractions, leading to questions about the true meaning of the values. The speaker proposes using the values as a ratio to calculate the required amounts for a given volume of water.

ch3m

Hi guys,
I'm facing a problem.
I've read a paper where they tried to synthesise a crystal and they give the following reaction mixture molar composition:
3.0 SiO2
1.0 Al2O3
0.1 NaCl
276 H2O

What does it means?
It can't be the molar fraction since the sum of all the fraction must give 1 as result.
I guess that it should be the mol of each compound in solution, but that means that they have almost 5 L of water... am I right?

ch3m said:
I guess that it should be the mol of each compound in solution, but that means that they have almost 5 L of water... am I right?

That's how I would read the information.

No idea why they reported it this way, perhaps that's a convention used in such papers.

Borek said:
That's how I would read the information.

No idea why they reported it this way, perhaps that's a convention used in such papers.

Thanks.

So can I take such values as a ratio??

I mean: 3.0:1.0:0.1:276

So if I fix a volume of 250 ml of water which means 13.877 mol, I need to divide the mols for 276 and then multiply for the ratio.
i.e. for Al2O3 --> 13.887*(1/276) and for NaCl 13.887*(0.1/276)
Right?

Looks OK.

1. What is reaction molar composition?

Reaction molar composition refers to the relative amounts of each substance (in moles) involved in a chemical reaction. It is often expressed as a ratio or percentage.

2. How is reaction molar composition calculated?

Reaction molar composition is calculated by dividing the number of moles of a specific substance by the total number of moles in the reaction. This can be determined from the balanced chemical equation.

3. Why is reaction molar composition important?

Reaction molar composition is important because it helps us understand the stoichiometry of a reaction and the amount of each substance that is needed or produced. It also allows us to predict the outcome of a reaction and determine the limiting reactant.

4. Can reaction molar composition change?

Yes, reaction molar composition can change depending on the conditions of the reaction. Factors such as temperature, pressure, and concentration can affect the ratio of substances involved in a reaction.

5. How is reaction molar composition used in the laboratory?

In the laboratory, reaction molar composition is used to measure and mix the correct amounts of substances for a reaction. It is also used to calculate the yield of a reaction and determine the purity of a product.