How many atoms are in a given mass of metal?

[Jetstream]

TL;DR Summary

I have some metal samples pure(ish) and want to know the number of atoms in each sample.

Hi all,

This may be simple chemistry, but I haven’t engaged this topic for a very long time.

I have an experiment where I need to measure the masses of some elemental (99%pure) metal cubes and I also want to know how many atoms of each element there are within them.

From memory, Avogadro’s number would be used, but from my understanding, does it not assume the same form of atomic packing in each metal sample?

How can I figure out the number of atoms in each metal sample cube?

Regards,
Adam

 

[berkeman]

Summary:: I have some metal samples pure(ish) and want to know the number of atoms in each sample.

Hi all,

This may be simple chemistry, but I haven’t engaged this topic for a very long time.

I have an experiment where I need to measure the masses of some elemental (99%pure) metal cubes and I also want to know how many atoms of each element there are within them.

From memory, Avogadro’s number would be used, but from my understanding, does it not assume the same form of atomic packing in each metal sample?

How can I figure out the number of atoms in each metal sample cube?

Regards,
Adam

Welcome to PF.

It's been a long time for me too working this kind of problem, but I think I would use the concept of atomic mass:

https://en.wikipedia.org/wiki/Atomic_mass

 

[anuttarasammyak]

Mass of cube / mass of atom would give you an answer.

 

[symbolipoint]

Jetstream, any packing would only affect volume. Your question does not go into density nor volume. You will use atomic mass values and Avogadro's Number.

 

[PeterDonis]

How can I figure out the number of atoms in each metal sample cube?

What information do you have to start with? You say you will measure the masses of each cube, but what else do you know? Do you know what kind of metal each cube is made of, or are you supposed to figure that out too?

 

[PeterDonis]

Moderator's note: Some off topic posts have been deleted.

 

[sophiecentaur]

What information do you have to start with?

Yes. That's essential to know. If you know the element then you can easily find out the atomic mass (tables of chemical elements). The number of atoms is like the sweets in a jar.

You will use atomic mass values and Avogadro's Number.

I think that wouldn't be necessary (see above). You can use Avogadro for the mass of a given volume of gas (converted for STP) because a Mole of gas at STP takes up 22.4l of volume. (remembered from school but I think it's right.) But solids pack differently.

Question needs to be specified more completely I think.

 

[chemisttree]

We teach that Avogadro # is the number of particles in 1 mole. How it is packaged is irrelevant.