# Convert Litres to Moles: Step-by-Step Guide

• ChemRookie
In summary, the conversation discusses the conversion of liters to moles and the various factors and equations involved. It is mentioned that without additional information, it is not possible to convert directly from liters to moles. The conversation also touches on the concept of concentration and ideal gases, as well as the use of formulas and tables for finding vapor pressure.
ChemRookie
How would you go about changing liters, like 1L into moles?

Thanks

You can't.Liters measure capacity or volume of fluids especially,while moles measure amount of substance.

Concentration is sometimes given in moles/liter.

Daniel.

ChemRookie said:
How would you go about changing liters, like 1L into moles?

Are you given the name of a substance in the liquid or solid phase? What about a density? If so, you can convert by way of:

$$n_m=\frac{V\rho}{N_Am}$$

where V is the volume in liters, $$\rho$$ is the density in kg/m3, NA is Avogadro's number, and m is the mass of an individual atom or molecule of your substance.

Without this information, however, dexter is right that the two can't be converted.

Again, I am only adding to what dextercioby and SpaceTiger have already said. It is not possible to convert a volume to a mole unit without another factor. Dextercioby said one of them (concentration) and SpaceTiger said the another way to work it out.

Going on what dextercioby said:

$$Moles \ (mol) = Volume \ (dm^3) \ \times \ Concentration \ (mol \ dm^3)$$

With concentration you can work out the number of moles. (Take note that the dm3 can be changed for any volume value if you know the conversion factors).

The Bob (2004 ©)

$mol \ dm^{-3}$,okay ?Or u can use the fraction line.

Daniel.

I'm not sure what sort of question you're looking to answer. The above posts are completely correct in that it doesn't make sense to convert moles to liters directly.

However, if you're learning about basic chemistry or thermodynamics and you're looking to change an IDEAL GAS from moles to liters, then you have the following equation:

$$22.4\text{L}\approx 1\text{mol}$$ for ideal gases at STP

This "constant" is due to the fact that ideal gases are presumed to be point masses and statically neutral at STP and therefore exhibit similar properties despite being different molecules. If it's not an ideal gas, you'll need the concentration, as others have said.

the info I have is:

a 1L container with 5mL of water helt at 20degcel

I need to find the vapour pressure. I'm supposed to use PV=nrt right?
how do I get n though?

U got the volume of water,u need the # of moles.

18 ml of water<------>18 g of water<------>1 mol

Daniel.

dextercioby said:
U got the volume of water,u need the # of moles.

18 ml of water<------>18 g of water<------>1 mol

Daniel.

huh?

I don't get it.

ChemRookie said:
huh?

I don't get it.
One gram of water is the same as 1ml of water.

You know that you have 5 ml but let's pretend you have 18ml (you will see why in a minute).

You can convert 18ml into 18g because it is water. Other substances will needed a different change factor.

Now you know the molecular formula of water (with is H2O). The molar mass of this is 18g ml-1.

To convert from mass to moles you have to use the equation:

$$moles \ (mol) = \frac{mass \ (g)}{molar \ mass \ (g \ mol^{-1})}$$

Therefore, 18g divided by 18g ml-1 is equal to 1 mole.

Use this equation find how many moles of water there are in 5 ml.

The Bob (2004 ©)

Can I just make sure that ChemRookie realizes that 'ml' means millilitres, not moles? I'm not convinced that there isn't some confusion going on here!

The Bob said:
One gram of water is the same as 1ml of water.

You know that you have 5 ml but let's pretend you have 18ml (you will see why in a minute).

You can convert 18ml into 18g because it is water. Other substances will needed a different change factor.

Now you know the molecular formula of water (with is H2O). The molar mass of this is 18g ml-1.

To convert from mass to moles you have to use the equation:

$$moles \ (mol) = \frac{mass \ (g)}{molar \ mass \ (g \ mol^{-1})}$$

Therefore, 18g divided by 18g ml-1 is equal to 1 mole.

Use this equation find how many moles of water there are in 5 ml.

The Bob (2004 ©)

thanks..now I get it.

ChemRookie said:
thanks..now I get it.
's alright.

The Bob (2004 ©)

ChemRookie said:
How would you go about changing liters, like 1L into moles?

Thanks

It isn't that hard, I think you just divide the element by the STP which is 22.4, and then you got your moles . You have to know a little chemistry though to know some of this but it really isn't that hard once you learn it.

by the way, do ChemRookie really understand the concept of moles, as he asked that question is the first place. if he don't, latter on he might use 18 to measure other things.

ChemRookie said:
the info I have is:

a 1L container with 5mL of water helt at 20degcel

I need to find the vapour pressure. I'm supposed to use PV=nrt right?

Wrong.
how do I get n though?

You do NOT need it.

how come? explain..what formula do I use then?

IF "5 ml" is 5 gm, rather than releasing 5ml water vapor in the liter container, you are dealing with a two phase system, water vapor in equilibrium with liquid water. The vapor pressure is determined by temperature alone.

Formula? You come up with one, and the Nobel committee will hand deliver your prize. You get vapor pressure from tables in which the blood, sweat, and tears of lab boffins from the last 150 years have been compiled, fit, reviewed, interpolated, cubic-splined, and converted from this system of units to that.

## 1. How do I convert litres to moles?

To convert litres to moles, you will need to know the molarity (M) of the solution. Molarity is the number of moles of solute per litre of solution. Once you have the molarity, you can use the formula moles = molarity x volume (in litres) to calculate the number of moles.

## 2. Why do we need to convert litres to moles?

Converting litres to moles is important in chemistry because it allows us to accurately measure the amount of a substance in a solution. Moles are a unit of measurement for the number of particles (atoms, molecules, ions) in a substance, while litres are a unit of volume. By converting from litres to moles, we can determine the concentration of a solution and use it in various calculations and experiments.

## 3. What is the relationship between litres and moles?

The relationship between litres and moles is based on the molarity of a solution. Molarity is calculated by dividing the number of moles of solute by the volume of the solution in litres. This means that the more moles of solute present in a given volume of solution, the higher the molarity will be.

## 4. Can I use any unit of volume to convert to moles?

No, you cannot use any unit of volume to convert to moles. The unit of volume must be in litres because molarity is based on the concentration of a solution in moles per litre. Using a different unit of volume, such as millilitres or gallons, would not give an accurate conversion to moles.

## 5. Is there a specific formula for converting litres to moles?

Yes, there is a specific formula for converting litres to moles. The formula is moles = molarity x volume (in litres). This formula is commonly used in chemistry to convert between the two units of measurement and is necessary to accurately measure the amount of a substance in a solution.

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