Question

G of potassium reacts with 16 g of oxygen to produce 94 g of potassium oxide

Answer 1

78g

Step-by-step explanation:

Given parameters:

Mass of oxygen gas = 16g

Mass of potassium oxide = 94g

Unknown:

Mass of reacting potassium = ?

Solution:

To solve this problem, we need to obtain a balanced reaction equation. Then determine the number of moles of the reactant and use it to find that of the other one.

Balanced equation:

4K + O₂ → 2K₂O

Number of moles of reacting oxygen;

Number of moles =
`(mass)/(molar mass)`

molar mass of O₂ = 2 x 16 = 32g/mole

Number of moles =
`(16)/(32)` = 0.5mole

From the reaction equation;

4 mole of K reacted with 1 mole of O₂;

x mole of K will react with 0.5 mole of O₂

Therefore, 4 x 0.5 = 2 moles of potassium.

Mass of potassium = number of moles x molar mass

Molar mass of potassium = 39g

Mass of potassium = 2 x 39 = 78g