# physical science

posted by .

calculate the molar mass ofthe substance. divide it by Avogadros number (6.02x10 to 23 power)
.)Hydrogen2

2/(6.02 x 10^23) = ??

hun i don't get it the teacher said first H2x1.00 and then (6.02xio^23) but i still don't get it can you help?

I assume you don't understand where the number two comes from and why 6.02 x 10^23 is used. Look on the periodic table and see that the element H has an atomic mass of 1.0, if we round to the nearest tenth. A mole of hydrogen atoms will weigh 1.0 grams. Hydrogen is a gas and normally occurs as the diatomic molecule, meaning that there are two hydrogen atoms, H2, in one molecule. So the molar mass is 2 x 1.0 = 2.0 g per mole as opposed to the atomic mass of 1.0 g per mole. There are 6.02 x 10^23 molecules in a mol of H2 molecules; therefore, the 2.0 grams represents 6.02 x 10^23 molecules. I assume your teacher is dividing 2.0g/6.02 x 10^23 molecules/mole = 3.32 x 10^-24 g for the mass of 1 molecule of hydrogen. The mass of 1 atom of H would be just 1/2 that or 1.66 x 10^-24 g. I hope this helps.

thanks it helps.

## Similar Questions

1. ### Physics

How many grams of water (H_2O) have the same number of oxygen atoms as 1.0 (mol} of oxygen gas?
2. ### Chemistry

If 406.6 g of a substance is dissolved in 879.1 g of cyclohexane solvent, the boiling point of the solution is 87.52 oC. Calculate the apparent molar mass (g/mol) of substance.
3. ### chemistry

This problem is from my chemistry book and I am having a little trouble with the intermediary steps: Barium metal crystallizes in a body- centered cubic lattice (atoms at lattice points only) The unit cell edge length is 502 pm, and …
4. ### chem

so i posted this question yesturday and got some help. which is the stuff below. can you look at the last thing i said which was the answer i got by doing what DrBob222 said to do and tell me if its correct.(the question is the first …
5. ### Chemistry

1. How many molecules does 36.0 grams of water represent?
6. ### chemistry

How do I calculate the number of atoms in a compound (not an element)?
7. ### How do I calculate the number of atoms in a compou

I have the mass of the amount of substance, and the molar masses. How do I do this?
8. ### in chem

calculate the mass of this sample: 1.05 * 10 to the power of 26 atoms of neon, Ne(g) I know that I have to first divide by the avagadros constant, then once get the moles I need to multiply by the molar mass of neon to get the grams, …
9. ### chemistry

Given that Avogadros's number is 6.02x10^23. Calculate the numbe of molecules present in 5.0moles of nitrogen gas -N2(g)
10. ### Chemistry

I had to do a lab and had to calculate the molar mass for a substance with this equation MM=Mrt/pv but we had to calculate the mass of the substance and its temperature experimently. My question is why did we have to boil the liquide …

More Similar Questions