Question

What is the number of moles of beryllium atoms in 36 g of be? 0.25 mol 4.0 mol 45.0 mol 320 mol?

Answer 1

Answer: Option (b) is the correct answer.

Step-by-step explanation:

It is known that number of moles of a substance is equal to the given mass of the substance divided by its molar mass.

Mathematically, Number of moles =
`\frac{mass}{/text{\molar mass}}`

Molar mass of beryllium is 9 g/mol. Hence, putting the given values into the above formula as follows.

Number of moles =
`\frac{mass}{/text{\molar mass}}`

=
`(36)/(9 g/mol)`

= 4 moles

Thus, we can conclude that the number of moles present in 36 grams of Be are 4 moles.

Answer 2

`\boxed{\text {4.0 mol}}`

Step-by-step explanation:

1 mol of Be = 9.012 g

`\text{Moles of Be} = \text{36 g Be} * \frac{\text{1 mol Be}}{\text{9.012 g Be}} = \text{4.0 mol Be}\\\\\text{There are }\boxed{\textbf{4.0 mol Be}} \text{ in 36 g of Be}`