Answer:
[tex]\boxed {\boxed {\sf About \ 4.82 *10^{24} \ atoms \ K_2CrO_4}}[/tex]
Explanation:
To convert from moles to atoms, Avogadro's Number must be used.
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.
[tex]6.022*10^{23} \ atoms \ K_2CrO_4 / 1 \ mol \ K_2CrO_4[/tex]
Use this number as a fraction.
[tex]\frac{6.022*10^{23} \ atoms \ K_2CrO_4}{1 \ mol \ K_2CrO_4}[/tex]
Multiply by the given number of moles (8.00).
[tex]8.00 \ mol \ K_2CrO_4 *\frac{6.022*10^{23} \ atoms \ K_2CrO_4}{1 \ mol \ K_2CrO_4}[/tex]
The moles of potassium chromate will cancel.
[tex]8.00 *\frac{6.022*10^{23} \ atoms \ K_2CrO_4}{1}[/tex]
The denominator of 1 can be ignored.
[tex]8.00 *(6.022 *10^{23} \ atoms \ K_2CrO_4)[/tex]
Multiply.
[tex]4.8176*10^{24} \ atoms \ K_2CrO_4[/tex]
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.
[tex]4.82 *10^{24} \ atoms \ K_2CrO_4[/tex]
There are about 4.82* 10²⁴ atoms of potassium chromate in 8.00 moles.
