Answer
1. 2 Cu + 1 O₂ 2 CuO
a. 1.59 moles CuO
b. 2.625 moles O₂
c. 4.88 moles CuO
Explanation
(1) The balanced equation will be
2 Cu + 1 O₂ 2 CuO
(a) If 101 grams of copper is used, how many moles of copper (II) oxide will be formed?
From the reaction;
2 moles Cu produced 2 moles CuO
Molar mass of Cu = 63.546 g/mol
Molar mass of CuO = 79.545 g/mol
That implies;
(2 mol x 63.546 g/mol) = 127.092 g Cu produced (2 mol x 79.545 g/mol) = 159.09 g CuO
Therefore, 101 g Cu will produce
[tex]\frac{101g\text{ }Cu}{127.092g\text{ }Cu}\times159.09g\text{ }CuO=126.43g\text{ }CuO[/tex]Therefore the mole of CuO produced = 126.43/79.545 = 1.59 moles
(b) If 5.25 moles of copper are used, how many moles of oxygen must also be used?
From the reaction;
2 moles Cu react with 1 mole O2
Therefore, 5.25 moles Cu will react with
[tex]\frac{5.25\text{ }mol\text{ }Cu}{2\text{ }mol\text{ }Cu}\times1\text{ }mol\text{ }O_2=2.625\text{ }mol\text{ }O_2[/tex]Hence, 2.625 moles of oxygen must be used.
(c) If 78.2 grams of oxygen react with copper, how many moles of copper (II) oxide will be produced?
First, convert 78.2 grams of oxygen to moles using the mole formula.
[tex]Mole=\frac{Mass}{Molar\text{ }mass}[/tex]Molar mass of O₂ = 31.998 g/mol
So,
[tex]Mole=\frac{78.2g}{31.998g\text{/}mol}=2.44\text{ }mol\text{ }O_2[/tex]The final step is to use the mole ratio in the balanced equation to determine the mole of CuO that will be produced.
From the equation;
1 mole of O₂ produces 2 moles of CuO
2.44 moles O2 will now produce (2.44 moles x 2) = 4.88 moles of CuO
Therefore, 4.88 moles of CuO will be produced