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Topic: Molar Concentration (Read 10444 times)
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Toy_03
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Molar Concentration
«
on:
October 10, 2005, 10:05:16 PM »
A 4.00mL aliquot of 0.001 M NaSCN is diluted to 25.0mL with 0.1 M HNO3
What is the Molar concentration of SCN (negative) in the diluted solution?
IS THE EQUATION: M1V1=M2V2
and is this right
0.001 M Na SCN x .400L=0.1 M HNO3 x .250L
4 x 10^-4=.025
4 x10^-4/.025L=.016M
«
Last Edit: October 10, 2005, 10:06:09 PM by Toy_03
»
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mike
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Re:Molar Concentration
«
Reply #1 on:
October 10, 2005, 10:10:31 PM »
equation is right, calculation is wrong.
1mL = 0.001L
M referes to concentration of SCN not HNO3
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Toy_03
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Re:Molar Concentration
«
Reply #2 on:
October 10, 2005, 10:26:18 PM »
A 4.00mL aliquot of 0.001 M NaSCN is diluted to 25.0mL with 0.1 M HNO3
What is the Molar concentration of SCN (negative) in the diluted solution?
IS THE EQUATION: M1V1=M2V2
and is this right
0.001 M Na SCN x .00400L=0.1 M HNO3 x .250L
4 x 10^-6=.025
4 x10^-6/.025L=1.6 x 10^-4
Is this right now or its still wrong.
I guess Im kinda confused on converting mL to Liters still.
Another question is : If all of the SCN (negative) is complexed with Fe3+ to FeNCS2+, what is the molar concentration of FeNCS2+
How do you do this???
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mike
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Re:Molar Concentration
«
Reply #3 on:
October 10, 2005, 10:28:57 PM »
Your math is wrong.
m1v1 = m2v2
m2 = m1v1/v2
m1 = initial cocentration of SCN
v1 = initial volume of SCN
v2 = vinal volume of SCN
Don't put the HNO3 concentration into this equation!
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There is no science without fancy, and no art without facts.
mike
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Re:Molar Concentration
«
Reply #4 on:
October 10, 2005, 10:30:37 PM »
similar post here:
http://www.chemicalforums.com/index.php?board=2;action=display;threadid=5136;start=msg22734#msg22734
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There is no science without fancy, and no art without facts.
Toy_03
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Re:Molar Concentration
«
Reply #5 on:
October 10, 2005, 10:46:55 PM »
I cant really understand the other thread. But I think I may have the problem now:
M2=M1V1/V2
Well For some odd reason I kept getting the same answer like I did before which is 1.6 x 10 ^-4...I really dont know what Im doing wrong.
M2=?
M1=0.001M NaSCN
V1=.00400L
V2=.025
?
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mike
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Re:Molar Concentration
«
Reply #6 on:
October 10, 2005, 10:55:09 PM »
Yes that answer is correct:
0.00016 mol.L
-1
It is just your working out that doesn't make any sense.
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