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DarkMatter

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Stoichiometry-limiting reactant-using dimensional analysis-help?
« on: January 17, 2013, 04:24:19 AM »

hi, ive been trying to figure out how to do some limiting reactant problems (stoic), i have to use dimensional analysis but i have no idea how to set it up using that method, so i watched some khan academy vids, but i want to check to make sure im doing my homework right...

77.3 g of nitrogen and 14.2 grams of hydrogen react. determine the maximum mass of ammonia that can be produced?

N2+3H2=2NH3

what i did:
77.3/28=2.76    2.76 mol of nitrogen
14.2/6=2.37      2.37 mol of Hydrogen
there's 3 mol of Hydrogen for every 1 mol of Nitrogen, so hydrogen is the limiting reactant
2.37/2.76=.858  .858 mol of hydrogen for 1 mol of nitrogen (idk why i did this)
2.37(2/3)= 1.58  1.58 mol of ammonia
1.58(17/1)= 26.86g of ammonia

answer: maximum of 26.86g of Ammonia can be produced
can someone check this? i may also post more questions if i have them, thank you to anyone who can *delete me*
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DarkMatter

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Re: Stoichiometry-limiting reactant-using dimensional analysis-help?
« Reply #1 on: January 17, 2013, 05:08:00 AM »

why did my post get changed at the end to *delete me*?

did i do something wrong?
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Borek

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Re: Stoichiometry-limiting reactant-using dimensional analysis-help?
« Reply #2 on: January 17, 2013, 06:09:06 AM »

14.2/6=2.37      2.37 mol of Hydrogen

What is molar mass of the molecular hydrogen?

why did my post get changed at the end to *delete me*?

Don't worry, it happens
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DarkMatter

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Re: Stoichiometry-limiting reactant-using dimensional analysis-help?
« Reply #3 on: January 17, 2013, 06:55:09 AM »

The molar mass of molecular hydrogen is 2.02 right? H2?
can someone just check to see if i did this right? i havent just thrown my homework on here...
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Borek

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Re: Stoichiometry-limiting reactant-using dimensional analysis-help?
« Reply #4 on: January 17, 2013, 06:58:39 AM »

The molar mass of molecular hydrogen is 2.02 right? H2?

So how many moles of hydrogen where there?

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DarkMatter

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Re: Stoichiometry-limiting reactant-using dimensional analysis-help?
« Reply #5 on: January 19, 2013, 03:36:39 PM »

ok, i understand my mistake now, mol of hydrogen was 7.03, so 79.7 maximum ammonia.

in the following equation i have no idea where to begin, because i don't know what the water does in the equation.

85 grams of silver nitrate is measured out and then dissolved in water. 30 grams of zinc powder is mixed in. determine the maximum mass of silver that can be produced.
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Borek

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Re: Stoichiometry-limiting reactant-using dimensional analysis-help?
« Reply #6 on: January 19, 2013, 10:11:27 PM »

in the following equation i have no idea where to begin, because i don't know what the water does in the equation.

85 grams of silver nitrate is measured out and then dissolved in water. 30 grams of zinc powder is mixed in. determine the maximum mass of silver that can be produced.