# Understanding Calculation of N (Number of Atoms)

• KiNGGeexD
In summary, the conversation discusses a calculation involving the number of atoms, represented by N, in a given substance. The speaker has difficulty understanding where the value for N comes from and requests clarification. The other person explains that N is equivalent to Avogadro's number and provides a simplified calculation using this value. The conversation ends with the speaker understanding and acknowledging the calculation.
KiNGGeexD

I was looking through my notes and came across this (above) I understand the calculation etc but I don't see where the number of atoms N was calculated?

I don't see where it has come fromAny help would be great thanks in advanced

Neat handwriting you are using to produce your notes...not nice you (they?) break the line between the minus sign and the 23, though...

28 gram is one mole
density is 0.81 g/cm3
so 28 gram is 28/0.81 = 35 cm3, right ? i.e. 35 cm3/mole

one mole is N_avogadro molecules and 35/(6 e23) = 5.8 e-23 cm3/molecule.

Take the ##\root 3 \of \ ## and you get something like 3.9 e-8 cm or 0.39 nm

It's the top calculation for latent heat I'm not sure about I get the surface tension one, but the one above makes no mention of N but must use it:)

Why don't you type the part of "your" notes that you have a question about ? I can hardly read what is to the left of ##{1\over 2} nN\epsilon##. Anyway, since we are talking J/mol, N=NA.

Would N in the top equation not be just Avergadros number?

Yes. Since we are talking J/mol, N=NA.

Ahh ok this calculation must just be rounded up because using avergadros number just now I obtained

1.95E-21 J

Thanks

## 1. What is the meaning of N (Number of Atoms)?

The number of atoms, represented by the variable N, is a measure of the total number of individual atoms present in a given substance or system.

## 2. How is N (Number of Atoms) calculated?

The calculation of N can vary depending on the context and system being studied. In general, it involves counting the number of atoms of a particular element or molecule present in a sample or system.

## 3. Why is understanding N (Number of Atoms) important in science?

Knowing the number of atoms is crucial for many scientific calculations and experiments, such as determining the molar mass of a substance, predicting chemical reactions, and understanding the properties of materials.

## 4. Can N (Number of Atoms) be a fraction or decimal?

No, N is always a whole number. Atoms are indivisible units, and therefore cannot be divided into fractions or decimals.

## 5. How does Avogadro's number relate to N (Number of Atoms)?

Avogadro's number, represented by the symbol NA, is a constant that represents the number of particles in one mole of a substance. This number is used to convert between the mass of a substance and the number of atoms or molecules present, making it essential in calculating N.

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