Answer :
ANSWER
The mass of oxygen is 12.279 grams
STEP-BY-STEP EXPLANATION:
From the question provided, you were given the volume of oxygen to be 17.2 liters.
Given information
The volume of oxygen = 17.2 liters
To find the mass of oxygen, we need to find the mole of oxygen first
Recall that, at S.T.P, 1 mole is equivalent 22.4L
Let the mole of oxygen be x
The next step is to find the mole of oxygen using the above relationship
[tex]\begin{gathered} 1\text{ mole }\rightarrow\text{ 22.4}L \\ x\text{ mole }\rightarrow\text{ 17.2L} \\ \text{Cross multiply} \\ 1\cdot\text{ 17.2 = x }\cdot\text{ 22.4} \\ 17.2\text{ = 22.4x} \\ \text{Divide both sides by 22.4} \\ \frac{17.2}{22.4}\text{ = }\frac{22.4x}{22.4} \\ x\text{ = 0.7679 mole} \end{gathered}[/tex]The mole of oxygen is 0.7679 mole
From the periodic table, the molar mass of oxygen is 15.99 g/mol
The next thing is to find the mass of oxygen using the mole formula
[tex]\begin{gathered} \text{Mole = }\frac{\text{ reacting mass}}{\text{ molar mass}} \\ \text{ 0.7679 = }\frac{\text{ reacting mass}}{\text{ 15.99}} \\ \text{Cross multiply} \\ \text{ reacting mass = 0.7679 }\cdot\text{ 15.99} \\ \text{ reacting mass = 12.279 grams} \end{gathered}[/tex]Therefore, the mass of oxygen is 12.279 grams