Question

How many carbon atoms are in a diamond (pure carbon) with a mass of 30 mg ? Express your answer using two significant figures.

Answer 1

Answer: There are
`0.015* 10^(23)` atoms of carbon

Step-by-step explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number
`6.023* 10^(23)` of particles.

To calculate the moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}=(0.03g)/(12g/mol)=0.0025moles` (1g=1000mg)

1 mole of carbon atom contains =
`6.023* 10^(23)` atoms of carbon

0.0025 mole of carbon contain =
`(6.023* 10^(23))/(1)* 0.0025=0.015* 10^(23)` atoms of carbon

There are
`0.015* 10^(23)` atoms of carbon

Answer 2

1.50×10²¹ atoms of C

Step-by-step explanation:

First of all, let's convert the mass into moles (mass (g) / molar mass)

0.030 g / 12 g/mol = 2.5×10⁻³ moles

Now, we can apply the Avogadro Number

1 mol has __ 6.02×10²³ atoms

2.5×10⁻³ mol would have (2.5×10⁻³ mol . NA) = 1.50×10²¹