Use the chemical equation to answer the question. 4K(s) + O₂(g) → 2K₂O(s) The molar mass of potassium (K) is 39 g/mol. The molar mass of oxygen (O) is 16 g/mol. How many grams of potassium are needed in the reaction to produce 23.5 grams of potassium oxide (K₂O)?
23.5 g
19.5 g
9.75 g
0.50 g
To determine the amount of potassium needed in the reaction to produce 23.5 grams of potassium oxide (K₂O), we need to calculate the molar mass of K₂O.
The molar mass of K₂O can be calculated by adding the molar masses of potassium (K) and oxygen (O) together:
Molar mass of K₂O = (2 x molar mass of K) + (1 x molar mass of O)
Molar mass of K₂O = (2 x 39 g/mol) + (1 x 16 g/mol)
Molar mass of K₂O = 78 g/mol + 16 g/mol
Molar mass of K₂O = 94 g/mol
Now, we can set up a proportion to calculate the amount of potassium needed:
(23.5 grams K₂O) / (94 g/mol K₂O) = (x grams K) / (39 g/mol K)
Cross-multiplying and solving for x, we get:
(23.5 grams K₂O) * (39 g/mol K) = (94 g/mol K₂O) * (x grams K)
x = (23.5 grams K₂O) * (39 g/mol K) / (94 g/mol K₂O)
x = 9.75 grams K
Therefore, 9.75 grams of potassium are needed in the reaction to produce 23.5 grams of potassium oxide (K₂O). The correct answer is 9.75 g.