Question

8. How many grams of oxygen gas are needed to reactwith 25.0 g of K according to the following equation?4 K(s) + O2(g) → 2 K20(s)a. 10.23 g 02b. 2.56 g 02c. 8.66 g 02d. 5.12 g 02

Answer 1

(d) 5.12 g O₂

Step-by-step explanation

Given:

Mass of oxygen = 25.0 g

Equation: 4 K(s) + O₂(g) → 2K₂O(s)

From the balanced equation for the reaction, 4 moles of K react with 1 mole of O₂.

Note that from the Periodic Table, 1 mole of K = 39.10 g and 1 mole of O₂ = 32.00 g

In grams, 4 x 39.10 g = 156.40 g K reacts with 32.00 g O₂

So 25.0 g K will react with:

`\frac{25.0\text{ }g\text{ }K\text{ }*32.00\text{ }g\text{ }O₂}{156.40\text{ }g\text{ }K}=5.115\text{ }g\text{ }O₂\approx5.12\text{ }g\text{ }O₂`

Therefore, 5.12 grams of O₂ are needed to react with 25.0 g of K