ADA 2009 Sample Test Number 41

[sonofswan93]

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41.) A 49-gram sample of sulfuric acid, H2SO4 (98 gmol -1) contains

A. 1 mol of S atoms.
B. 16.0 grams of O.
C. 2.0 grams of H.
D. 2 moles of O atoms.
E. 1 mole of molecules.

The answer is D but im not really sure how to approach this problem.

Thank you guys for your help!

 

[sonofswan93]

My bad guys this is a 2000 ADA test sorry about that!

 

[OrphanageCaretaker]

The answer should be D. 2 moles of O atoms. The problem says that H2SO4 is 98 g/mol; 49 g is exactly half of that given. So in the makeup of the molecule, there are 4 moles of Oxygen. You would need to half that because it asks for half of the molecules's molecular mass aka 98 divided by 49 =2. 4 moles of oxygen divided by 2 is 2 moles. Thus your answer should be 2 moles of O atoms.

 

[sonofswan93]

Thank you so much that makes sense now! Love your profile pic by the way haha 🤣

 

[OrphanageCaretaker]

Thank you so much that makes sense now! Love your profile pic by the way haha 🤣

No problem and thank you.