Question

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

Answer 1

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.

Step-by-step explanation:

• For a:

We are given 1 mole of each helium and argon gas. To calculate the number of atoms of each gas, we use mole concept.

According to mole concept:

1 mole of an element contains
`6.022* 10^(23)` number of atoms.

So, 1 mole of helium gas will contain
`1* 6.022* 10^(23)=6.022* 10^(23)` atoms.

And, 1 mole of argon gas will contain
`1* 6.022* 10^(23)=6.022* 10^(23)` atoms.

Hence, both the gases have same number of atoms.

• For b:

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

`Moles=\frac{\text{Given mass}}{\text{Molar mass}}`

• For helium:

Molar mass = 4 g/mol

Number of moles = 1 mole

Putting the values in above equation, we get:

`1mole=\frac{\text{Given mass}}{4g/mol}=4grams`

• For Argon:

Molar mass = 39.95 g/mol

Number of moles = 1 mole

Putting the values in above equation, we get:

`1mole=\frac{\text{Given mass}}{39.95g/mol}=39.95grams`

Difference in mass of argon and helium = (39.95 - 4)g = 35.95g

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