Question

No of atoms in 0.5 mole of potassium dichromate

Answer 1

Hello!

By the Law of Avogrado we understand that 1 mol of a substance is equivalent to 6.02x10²³ molecules, therefore:
1 mol → 6.02*10²³ atoms
0.5 mol → y
$\dfrac{1}{0.5} = \dfrac{6.02*10^{23}}{y}$
Product of extremes equals product of means:

$1*y = 0.5*6.02*10^{23}$

$\boxed{\boxed{y = 3.01*10^{23}\:atoms}}\end{array}}\qquad\checkmark$

I Hope this helps, greetings ... DexteR!

Answer 2

3 * 10²³ is the correct answer