The number of potassium atom that are in 0.25 moles potassium carbonate is calculated as follows
by use of Avogadro contant
1 mole= 6.02 x10^23 atoms
what about 0.25 moles,
by close multiplication
{0.250 moles x 6.02 x10^23} / 1 mole = 1.505 x10^23 atoms