A 1.59 mol sample of Kr has a volume of 641 mL. How many moles of Kr are in a 4.41 L sample at the same temperature and pressure?

The correct answer is 10.939 mol ≅ 10.94 mol

Explanation:

According to Avogadro's gases law, the number of moles of an ideal gas (n) at constant pressure and temperature, is directly proportional to the volume (V).

For the initial gas (1), we have:

n₁= 1.59 mol

V₁= 641 mL= 0.641 L

For the final gas (2), we have:

V₂: 4.41 L

The relation between 1 and 2 is given by:

n₁/V₁ = n₂/V₂

We calculate n₂ as follows:

n₂= (n₁/V₁) x V₂ = (1.59 mol/0.641 L) x 4.41 L = 10.939 mol ≅ 10.94 mol

Iron has two ionic states of +2 and + 3. The formula for iron oxide with the Fe + 2 is FeO. The formula for iron oxide with The Fe+3 is Fe2O3. Using the atomic mass of Fe as 55.845 gr/mole and O as 15.999 gr/mole the percent Fe of FeO is 77.73% and of Fe2O3 is 69.94%.