# AS Moles (2)

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#1
Q1. The concentration of sodium chloride in a solution is 0.0324 mmole/dm3.
Calculate the mass of sodium chloride presence in the solution in mg.
1mole=1000milimole (mmole)

Q2. Calculate the total volume of gases remains in the reacting vessel just after completing
the reaction when 3 moles of ethane is burnt with 262 dm3 of oxygen.
C2H6 (g) + 3.5 O2 (g) = 2 CO2 (g) +3 H2O(g)
Last edited by Aleksander Krol; 2 months ago
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2 months ago
#2
For Q1 you can start by converting the mmol to mols then you’ll have mol/dm3 then multiply by molar mass to calculate the mass(g) per dm3 and convert to mg
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#3
(Original post by TheKira)
For Q1 you can start by converting the mmol to mols then you’ll have mol/dm3 then multiply by molar mass to calculate the mass(g) per dm3 and convert to mg
i get 1.9mg for the Q1, is that correct?
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#4
(Original post by Aleksander Krol)
i get 1.9mg for the Q1, is that correct?
(Original post by TheKira)
For Q1 you can start by converting the mmol to mols then you’ll have mol/dm3 then multiply by molar mass to calculate the mass(g) per dm3 and convert to mg
and for Q2. i get 370 dm^3
is that right?
0
2 months ago
#5
(Original post by Aleksander Krol)
i get 1.9mg for the Q1, is that correct?
I got 1.8954mg (/ dm3) so I will assume so
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2 months ago
#6
(Original post by Aleksander Krol)
and for Q2. i get 370 dm^3
is that right?
Send me your working so I can see how you approached the question
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#7
(Original post by TheKira)
Send me your working so I can see how you approached the question
*C2H6 - - - - - O2
1 - - - - - - - - - 3.5
3 - - - - - - - - - -x =(10. 5 moles)
O2(g) : 262/24 = 10.9 moles
(10.9x24) - (10.5x24)= 9.6 dm^3

*C2H6 - - - - - - CO2
1 - - - - - - - - - - - - -2
3 - - - - - - - - - - - - -x=(6 moles)
CO2(g) : 6x24= 144 dm^3

*C2H6 - - - - - - - - - H2O(g)
1 - - - - - - - - - - - - - - - 3
3 - - - - - - - - - - - - - - - x= (9 moles)
H2O(g) : 9x24= 216 dm^3

Total Volume of Gases: 9.6+144+216 = 370 dm^3
Last edited by Aleksander Krol; 2 months ago
1
#8
(Original post by TheKira)
I got 1.8954mg (/ dm3) so I will assume so
yess that's what i got too
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