Question

Calculate the number of ions present in 7.45 grams of potassium oxide.
( At.mass of K= 39u).

Answer 1

=> Number of moles of K2O in given sample = Total mass/molar mass

= 7.45/(39 + 39 + 16)
= 7.45/94

=> Number of molecules = Number of moles x Avogadro's Number
= (7.45/94) x N

=> Number of ions = Number of molecules x 3

= (7.45/94) x N x 3

Answer 2

calculate the number of potassium ions present in 7.45g of potassium oxide(atomic mass ofK=39u)

Answer 3

Formula of potassium oxide is K2O.
Molar mass of K2O =(39x2)+16=94g/mol
No.of moles of K2O=Mass in gram/Molar mass=7.45g/94g/mol=0.079mol.
1 mole of K2O contains molecules=6.022x10²³
Therefore,0.079 mole of K2O contains molecule=6.022x10²³x0.079
=0.476x10²³
=0.476x10²² molecules
since each molecule of K2O contains two potassium ions(K+),total number of potassium ion is given by 4.76x10²²x2=9.52x10²²ions.

Answer 4

9.25×1022 ions