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Topic: Help me with concentration please!!! (due tomorrow) T_T  (Read 3980 times)

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Offline michael2lee

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Help me with concentration please!!! (due tomorrow) T_T
« on: November 14, 2010, 09:24:24 PM »
Given that 0.1M sodium thiosulfate(HYPO) and 1M of HCl
I need to know the concentration of HYPO of the 5 solution below

50ml HYPO + 5ml HCl
40ml HYPO + 10ml Water + 5ml HCl
30ml HYPO + 20ml Water + 5ml HCl
20ml HYPO + 30ml Water + 5ml HCl
10ml HYPO + 40ml Water + 5ml HCl

Help me please T_T

Offline Fluorine

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #1 on: November 14, 2010, 09:37:43 PM »
"4.) Please show that you've at least attempted the problem.  We don't mind helping you solve problems but we are ethically opposed to doing homework for you. Violators will have their topic deleted or locked."

How many moles of "HYPO" in 50mL solution? What is the total volume of the solution if 50mL "HYPO" and 5mL HCl are mixed. Can't you calculate the molarity from here?

Hint: Molarity = mol/V (liters)
I'm still learning - always check my work/answer.

"curse Pierre Jules César Janssen!"

Offline michael2lee

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #2 on: November 14, 2010, 09:53:26 PM »
I got 50% for 50ml of HYPO and 5ml of HCl
Could you please check if i am right on this??
I used
0.1*0.05/(0.1*0.05) + 0.005

Offline Fluorine

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #3 on: November 14, 2010, 10:09:52 PM »
I can't keep up with your work if it's not labeled. This is how I'd approach it, though I can't promise it's correct.

50mL HYPO/1000 = 0.05L HYPO
5mL HCL/1000 = 0.005L HCL

Moles:
0.05L HYPO x 0.1M HYPO = 0.005mol HYPO

Volume:
0.05L HYPO + 0.005L HCl = 0.055L (solution)

Molarity:
0.005mol HYPO/0.055L = 0.09M HYPO
I'm still learning - always check my work/answer.

"curse Pierre Jules César Janssen!"

Offline michael2lee

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #4 on: November 14, 2010, 10:14:54 PM »
say 40ml of HYPO
 than would it be 0.004Mole HYPO/0.055L?

Offline Fluorine

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #5 on: November 14, 2010, 10:21:40 PM »
If it's for the second one, yes.

40ml HYPO + 10ml Water + 5ml HCl.
0.004mol HYPO/0.04L HYPO + 0.01L H2O + 0.005L HCl = 0.004mol/0.055L

However if you're just asking the first with 40mL HYPO, then;

0.004mol HYPO/0.04L HYPO + 0.005L HCl = 0.004mol HYPO/0.045L
I'm still learning - always check my work/answer.

"curse Pierre Jules César Janssen!"

Offline michael2lee

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #6 on: November 14, 2010, 10:23:16 PM »
Thanks a bunch T_T
Just working off on my lab report due tomorrow T_T

Offline Fluorine

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Re: Help me with concentration please!!! (due tomorrow) T_T
« Reply #7 on: November 14, 2010, 10:31:26 PM »
Again, always recheck my work. I'm a student as well and can be mistaken. Glad to help though.
I'm still learning - always check my work/answer.

"curse Pierre Jules César Janssen!"

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