how many moles.....

[ManzRDH]

How many moles of H2O are produced in the combustion of 20g of glucose in excess 02?

a-2/3
b-1/3
c-2/6
d 1/6
e none

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[Dentist 2 be]

1) write a balanced equation:

C6H12O6 + 6O2 --------> 6 H2O + 6CO2
(1 mol) (6 mol) (6 mol) (6 mol)

20g C6H12O6 (glucose)

2) convert substance being combusted into moles

C6H12O6 : Molecular weight = 180 g/mol

So, 20g/180g/mol = 1/9 mol of glucose

1 mol C6H12O6 : 6 mol H2O
1/9 mol C6H12O6 : X mol H2O


x = 6/9 = 2/3 mol H2O

So, the correct answer is A

 

[ManzRDH]

Thanks for your help. I purchased these cd's from someone on ebay. He put it together for DAT prep but I found some mistakes. I just wanted to make sure since CG isn't my strong point.