Question

Determine the number of molecules of Cr2O3 that are formed when 1.34x10^3 grams of oxygen completely reacts according to the following equation 4Cr(s) + 3O₂(g) → 2Cr₂O₃(s)Answer as equation

Answer 1

1.68x10^25 molecules of Cr2O3 are formed

Step-by-step explanation:

1st) From the balanced reaction we know that 4 moles of Cr reacts with 3 moles of O2 to produce 2 moles of Cr2O3.

2nd) With the stoichiometry of the reaction, the given value of 1.34x10^3 grams of oxygen, the molar mass of oxygen (32g/mol) and the Avogadro's number (6.022*10^23 molecules/mol), we can calculate the number of molecules of Cr2O3:

`1.34*10^3g\text{ O}_2*\frac{1\text{ mol O}_2}{32g\text{ O}_2}*\frac{2\text{ moles Cr}_2\text{O}_3}{3\text{ moles O}_2}*\frac{6.022\text{x10}^(23)\text{ molecules}}{1\text{ mol}}=1.68\text{x10}^(25)\text{ molecules}`

So, 1.68x10^25 molecules of Cr2O3 are formed.