Solve this task.

Question

Determine the mass of copper (I) sulfid which can be oxidized with 7.8 x 10²³ oxygen molecules. Reaction products are copper (I) oksid and sulfur (IV) oxide.

Answer 1

First, we need to write a balanced equation:

2 Cu₂S + 3 O₂ → 2 Cu₂O + 2 SO₂

Next, we need to molar mass of copper I) sulfide: ~ 159.2 g/mole

Now, using that info, along with Avogadro's Number & the stoichiometry of the reaction, we can calculate the answer:

(159.2 g Cu₂S/1 mol Cu₂S) (2 mol Cu₂S/ 3 mol O₂) (1 mol O₂/ 6.023 x 10²³ molecules of O₂) 7.8 x 10²³ molecules of O₂ = 137.4 g = 1.4 x 10² g of Cu₂S (to 2 sig figs)