the # of molecules in 1g of H2 is?

Answer 1

The molecular weight of H2 is 2 g/mol, so 1 g is 0.5 mol, so,
0.5 mol * 6.02*10^23 molecules/mol = 3.01*10^23 molecules.

Don't you hate it when someone puts in a placeholder with an incomplete answer, then goes back and fills in the rest of the answer at their leisure, simply so they can have the top spot?

Answer 2

1 g of H2 is half a mole of H2 since the mass of H is 1 g/mol.

One mole contains 6.02 x 10^23 molecules, so 1/2 a mole contains 3.01 x 10^23 molecules.

Answer 3

H2 is 2 grams per mole, and one mole contains 6.023*10^23 particles. Therefore one gram of H2 consists of 6.023*10^23/2 or about 3.01*10^23 molecules!

Answer 4

3.011 x 10^23 H2 molecules.

Solution:
get the number of moles then multiply it with the avogadro's number.