General chemistry questions

[ibo man]

I will appreciate i if I could get help with this few general chemistry questions. I don't why I couldn't figure out how they got the answers.
1) A 49 gram sample of sulfuric acid, H2SO4 (98g/mol), 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. I mole of molecules.
The correct answer to the above question is D.

2) If 1 mole of N2 (nitrogen gas) and 1 mole of H2 (hydrogen gas) are mixed and allowed to react according to the equation N2+3H2 ---> 2NH3, the maximum number of moles of NH3 that could be produced is
A. 2/3.
B. 3/2.
C. 2/1.
D. 1/2.
E. 1/1.
The correct answer to the above question is A.

I will appreciate it very much if I could get some help

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[DATMATT]

1. 49g(1 mol/98g)= 0.5 molH2SO4

0.5 mol H2SO4(4 mol of O atoms/1 mol H2SO4)= 2 mol O atoms

2. N2+3H2 ---> 2NH3

1 mol of H2 limits the product. (if you used 1 mol of N2 you would still be short 2 moles of H2)

Also, for every 2 mols NH3 made, 3 mols of H2 are used

1 mol H2(2 mol NH3/3mol H2)= 2/3 mol NH3 made

Hopes this helps....

Matt

 

[ibo man]

DATMATT,
Thank you very much for clearifying that for me.