Question

8. How many oxygen atoms are in 25 g of oxygen?

1.9 × 1024 atoms
2.4 × 1026 atoms
9.4 × 1023 atoms
1.5 × 1025 atoms

Answer 1

9.4 × 10²³ atoms

Step-by-step explanation:

To find the number of entities in a given substance we use the formula

N = n × L

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

However we weren't given the number of moles only the mass of oxygen was given. we can find the number of moles from that by using the formula

`n = (m)/(M) \\`

m is the mass

M is the molar mass

n is the number of moles

Molar mass of oxygen = 16 g/mol

mass in question = 25 g

We have

`n = (25)/(16) = 1.56 \\`

number of moles = 1.56 mol

The number of oxygen atoms is equal to

N = 1.56 × 6.02 × 10²³ = 9.3912 × 10²³

We have the final answer as

9.4 × 10²³ oxygen atoms

Hope this helps you