Question

Convert 15.2 moles of K to atoms of K.

Answer 1

`\boxed {\boxed {\sf 9.15*10^(24) \ atoms \ K}}`

Step-by-step explanation:

To convert atoms to moles, Avogadro's Number must be used: 6.022*10²³.

This tells us the amount of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case it is the atoms of potassium. We can create a ratio.

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

Multiply by the given number of moles: 15.2

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

The moles of potassium cancel.

`15.2 *\frac {6.022*10^(23) \ atoms \ K }{ 1 }`

The denominator of 1 can be ignored.

`15.2 * {6.022*10^(23) \ atoms \ K }{`

Multiply.

`9.15344*10^(24) \ atoms \ K`

The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we calculated that is the hundredth place. The 3 in the thousandth place tells us to leave 5.

`9.15*10^(24) \ atoms \ K`

In 15.2 moles of potassium, there are 9.15*10²⁴ atoms of potassium.