Small samples of oxygen gas needed in the laboratory can be generated by any number of simple chemical reactions, such as 2 KCl (s) → 2 KCl (s) + 3 (g)
What mass of oxygen (in grams) is produced when 122.6 g of KCl (formula mass = 122.6 amu) takes part in this reaction?

Question

Small samples of oxygen gas needed in the laboratory can be generated by any number of simple chemical reactions, such as 2 KCl  (s) → 2 KCl (s) + 3  (g)
What mass of oxygen (in grams) is produced when 122.6 g of KCl  (formula mass = 122.6 amu) takes part in this reaction?

Quizplus · Accepted Answer

From the balanced chemical equation, 2 moles of KCl produce 3 moles of O2. Therefore, 1 mole of KCl produces 3/2 moles of O2. 
122.6 g of KCl is equal to 1 mole of KCl. 
So, 1 mole of KCl produces (3/2) moles of O2. 
The molar mass of O2 is 32 g/mol. 
Therefore, (3/2) moles of O2 produces (3/2) x 32 = 48 g of O2. 
Hence, the answer is B, 48.00 grams.

Small Samples of Oxygen Gas Needed in the Laboratory Can