Question

What is the atomic mass of an element if 4.00 grams of it contains 2.98x10^22 atoms

Answer 1

Atomic mass is the same as the grams per mole. 2.98x10²² is 0.0495 mol (2.98e22 ÷ 6.02e23). If we have 4 g/0.0495 mol, that's 80.81 g/mol, so the atomic mass is 80.81 amu. Make sense?

Answer 2

Answer: The molar mass of the element is 80.8 g/mol

Step-by-step explanation:

We are given:

Number of atoms =
`2.98* 10^(22)`

According to mole concept:

`6.022* 10^(23)` number of atoms are contained in 1 mole of an element

So,
`2.98* 10^(22)` number of atoms will be contained in
`(1)/(6.022* 10^(23))* 2.98* 10^(22)=0.0495mol` of an element

To calculate the molar mass for given number of moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}`

Given mass of element = 4.00 g

Moles of an element = 0.0495 moles

Putting values in above equation, we get:

`0.0495mol=\frac{4.00g}{\text{Molar mass of element}}\\\\\text{Molar mass of an element}=(4.00g)/(0.0495mol)=80.8g/mol`

Hence, the molar mass of the element is 80.8 g/mol