Answer:
Step-by-step explanation:
To calculate the grams of potassium that reacted, we need to determine the molar ratio between potassium and potassium oxide using the balanced chemical equation.
The balanced chemical equation for the reaction between potassium and oxygen is:
4K + O2 → 2K2O
According to the equation, 4 moles of potassium react to form 2 moles of potassium oxide.
To find the number of moles of potassium oxide formed, we can use its molar mass. The molar mass of potassium oxide (K2O) is:
2(39.10 g/mol) + 16.00 g/mol = 78.20 g/mol
Now, let's calculate the number of moles of potassium oxide formed:
moles of potassium oxide = mass / molar mass
moles of potassium oxide = 28.2 g / 78.20 g/mol
moles of potassium oxide ≈ 0.360 moles
According to the balanced chemical equation, the molar ratio between potassium and potassium oxide is 4:2, which simplifies to 2:1. Therefore, for every 2 moles of potassium oxide formed, 1 mole of potassium reacts.
Now, let's calculate the number of moles of potassium that reacted:
moles of potassium = 0.360 moles / 2
moles of potassium = 0.180 moles
Finally, we can calculate the grams of potassium that reacted:
grams of potassium = moles of potassium × molar mass of potassium
grams of potassium = 0.180 moles × 39.10 g/mol
grams of potassium ≈ 7.02 g
Therefore, approximately 7.02 grams of potassium reacted to form 28.2 grams of potassium oxide.