Compare (a) the numer of atoms and (b) the number of grams present in 1.00 mole of helium and 1.00 mole of argon

For a: The number of atoms of both the gases remains the same.

For b: The number of grams of 1 mole of argon is more than 1 mole of helium by 35.95 grams.

Explanation:

To calculate the number of atoms, we use mole concept.

According to mole concept:

1 mole of an element contains number of atoms.  

We are given two gases of same number of moles.

Therefore, 1 mole of helium gas will contain number of atoms.

and, 1 mole of argon gas will contain number of atoms.

Hence, number of atoms of both the given gases remains the same.

As, the molar mass of both the gases are different, so their masses in 1 mole will be different.

To calculate the number of moles, we use the equation:

Molar mass of helium = 4 g/mol

Putting the values in above equation, we get:  

Molar mass of Argon = 39.95 g/mol

Putting the values in above equation, we get:  

Calculating the difference of masses of both the gases = (39.95 - 4)g = 35.95g

Therefore, the mass of argon is more than mass of helium by 35.95 grams.