Question

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

Answer 1

Answer:

78g

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 = $\frac{mass}{molar mass}$

molar mass of  O₂ = 2 x 16 = 32g/mole

     Number of moles = $\frac{16}{32}$  = 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