Question

Convert 1.25 x 1024 atoms of carbon to moles of carbon.

Answer 1

2.076

Step-by-step explanation:

1 mole is 6.02 * 10^23

To convert from atoms (or molecules or compounds or ions etc.) to mols, you divide the number of atoms (or molecules or etc.) by 6.02 * 10^23

So it is (1.25 * 10^24)/(6.02 * 10^23)

=2.076

Answer 2

`\boxed {\boxed {\sf 2.08 \ mol \ C}}`

Step-by-step explanation:

We are asked to convert a number of carbon atoms to moles.

We will use Avogadro's Number for this, which is 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. For this problem, the particles are atoms of carbon. There are 6.022 ×10²³ atoms of carbon in 1 mole of carbon.

We will also use dimensional analysis to solve this problem. To do this, we use ratios. Set up a ratio using the underlined information.

`\frac {6.022 * 10^(23) \ atoms \ C}{1 \ mol \ C}`

We are converting 1.25 ×10²⁴ atoms of carbon to moles, so we multiply the ratio by that value.

`1.25 * 10^(24) \ atoms \ C* \frac {6.022 * 10^(23) \ atoms \ C}{1 \ mol \ C}`

Flip the ratio. It remains equivalent, but it allows us to cancel the units atoms of carbon.

`1.25 * 10^(24) \ atoms \ C* \frac{1 \ mol \ C} {6.022 * 10^(23) \ atoms \ C}`

`1.25 * 10^(24) * \frac{1 \ mol \ C} {6.022 * 10^(23) }`

`\frac{1.25 * 10^(24) } {6.022 * 10^(23) } \ mol \ C`

`2.075722351 \ mol \ C`

The original measurement of atoms has three significant figures, so our answer must have the same. For the number we calculated, that is the hundredths place. The 5 in the thousandths place tells us to round the 7 up to an 8.

`2.08 \ mol \ C`

1.25 ×10²⁴ atoms of carbon is equal to approximately 2.08 moles of carbon.