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If we start with 9.0 grams of H2O, how many moles of H2 will be produced?Answer the...

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tdj4325 | Salutatorian

Posted June 19, 2012 at 1:51 AM via web

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If we start with 9.0 grams of H2O, how many moles of H2 will be produced?

Answer the question using the balanced equation below: 2 K + 2 H2O → 2 KOH + H2 If we start with 9.0 grams of H2O, how many moles of H2 will be produced? Show your work, including all conversion factors and all units.

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thilina-g | College Teacher | (Level 1) Educator

Posted June 19, 2012 at 3:28 AM (Answer #1)

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Weight of H2O = 9 g

The number of mols of H2O = 9 g/ 18 g per mol

                                         = 0.5 mol

According to stoichiometry of the given equation, 2 mols of H2O will give 1 mol of H2.

Therefore H2 produced by 0.5 mol of H2O is,

 = 1/2 x 0.5 mol = 0.25 mol

Therefore 0.25 mol of H2 is produced.

 

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chaobas | College Teacher | Valedictorian

Posted June 20, 2012 at 1:10 AM (Answer #2)

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the balanced reaction is 

2 K + 2 H2O → 2 KOH + H2

 

now we have 9 g of water and the molar mass of water is 18g/mol

 

moles = mass/molar mass

 

moles of water = 9g/18(g/mol) =0.5 mol H2O

if we look ta the reaction the molar ratio is 2 H2O : 1 H2

that is 2  mol of water will produce 1 mol of H2

0.5 mol H2O*(1 mol H2/ 2 mol H2O)

0.25 mol H2

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