How many moles are there in 8 g of oxygen gas, O$_2$? (O = 16)
A0.25 molCORRECT
B2 mol
C4 mol
D0.5 mol
JUPEBChemistryStoichiometry and Volumetric Analysis
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Why the answer is A, and why the others tempt you.
The molar mass of O$_2$ is 32 g mol$^{-1}$, so moles $= \dfrac{8}{32} = 0.25$. Using the atomic mass 16 instead of the molecular mass gives 0.5.
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