Se sabe que 10 g de calcio reaccionan con 4 g de oxígeno para obtener 14 g de óxido de calcio. Indica la cantidad de óxido de calcio que se obtiene al hacer reaccionar cantidades iguales de calcio y oxígeno (por ejemplo, 50 g de cada uno)

69.9 g of CaO will be produced. ≅ 70 g

Explanation:

First of all you need to make the reaction:

2Ca + O₂ → 2 CaO

Determine the moles of each reactant:

10 g Ca / 40.08 g/mol = 0.25 moles

4 g O₂ / 32 g/mol = 0.125 moles

There is no limiting reagent in this reaction, we can use both elements.

Ratio between Ca and CaO, is 2:2. For 0.25 moles of Ca I would make 0.25 moles of CaO. We convert the moles to mass:

0.25 mol . 56.08 g / 1mol = 14 g

Let's think when you have the same mass of reactant:

50 g Ca/ 40.08 g/mol = 1.24 moles

50 g O₂ / 32 g/mol = 1.56 moles

For 1 mol of oxygen I need 2 moles of calcium, so If I have 1.56 moles, I would need the double, 3.12. Notice that Ca is the limiting reagent (we need 3.12 moles of reactant, but we only have 1.24). Now we need to work with it. If 2 moles of Ca, makes 2 moles of CaO, then 1.24 moles, will produce the same amount of oxide. We finally convert the moles to mass: 1.24 mol . 56.08 g/mol = 69.9 g