Question

How many atoms are in 8.00 moles of potassium chromate?​

Answer 1

481.6x10^23

Step-by-step explanation:

Answer 2

`\boxed {\boxed {\sf About \ 4.82 *10^(24) \ atoms \ K_2CrO_4}}`

Step-by-step explanation:

To convert from moles to atoms, Avogadro's Number must be used.

• 
  `6.022*10^(23)`

This number tells us how many particles (atoms, molecules, ions. etc.) in 1 mole of a substance. In this case, it is atoms of potassium chromate (K₂CrO₄) in 1 mole.

`6.022*10^(23) \ atoms \ K_2CrO_4 / 1 \ mol \ K_2CrO_4`

Use this number as a fraction.

`(6.022*10^(23) \ atoms \ K_2CrO_4)/(1 \ mol \ K_2CrO_4)`

Multiply by the given number of moles (8.00).

`8.00 \ mol \ K_2CrO_4 *(6.022*10^(23) \ atoms \ K_2CrO_4)/(1 \ mol \ K_2CrO_4)`

The moles of potassium chromate will cancel.

`8.00 *(6.022*10^(23) \ atoms \ K_2CrO_4)/(1)`

The denominator of 1 can be ignored.

`8.00 *(6.022 *10^(23) \ atoms \ K_2CrO_4)`

Multiply.

`4.8176*10^(24) \ atoms \ K_2CrO_4`

The original measurement of moles (8.00) has 3 significant figures, so we must round our answer to 3 sig figs.

For the number we calculated, that is the hundredth place. The 7 in the thousandth place tells us to round the 1 up to a 2.

`4.82 *10^(24) \ atoms \ K_2CrO_4`

There are about 4.82* 10²⁴ atoms of potassium chromate in 8.00 moles.