Can't solve this calculation problem!

[nextyearrx]

Advertisement - Members don't see this ad

I have been trying to solve this problem but not getting the right and easy way to solve this.

Q: How many milliosmoles/L are there in 1L of a NaCl solution containing 1mEq of sodium ion in each 20 mL?

The way I do is: NaCl-->Na + Cl

mEq=mmol*valance
1=mmol*2
therefore, mmol=0.5

Now 20ml contains--> 0.5mOsm
So 1000mL will contain 0.5*1000 / 20 = 25mOsm

But the answer is 100mOsm😳 I have no idea how the answer is 100..

 

[waiter]

1 mEq NaCL dissociates into 2 mOsm
(1 mEq/20 ml)(2 mOsm/mEq)(1000 ml) = 100 mOsm

 

[Silverlove]

I have been trying to solve this problem but not getting the right and easy way to solve this.

Q: How many milliosmoles/L are there in 1L of a NaCl solution containing 1mEq of sodium ion in each 20 mL?

The way I do is: NaCl-->Na + Cl

mEq=mmol*valance
1=mmol*2
therefore, mmol=0.5

Now 20ml contains--> 0.5mOsm
So 1000mL will contain 0.5*1000 / 20 = 25mOsm

But the answer is 100mOsm😳 I have no idea how the answer is 100..

The answer is 100 mOsmol, so that is correct.

1 mEq = 20 mL, thus 1000 ml = 50 mEq

1 mEq= 58.5 mg, thus 50 mEq = 2925 mg

1 mmol = 58.5 mg, thus 2925 mg = 50 mmol

1 mmol = 2 mOsmol, thus 50 mmol = 100 mOsmol. Hope that helps.

 

[npage148]

I thought you used 1.8 instead of two for monoprotic salts to account for incomplete ionization or is that only when it's a salt of a weak acid/base?

 

[radio frequency]

I thought you used 1.8 instead of two for monoprotic salts to account for incomplete ionization or is that only when it's a salt of a weak acid/base?

Pretty sure that's only true in regards to weak acids or bases. From my memories of general chemistry, NaCl is completely ionized. Here's a little more on the subject: http://www.science.uwaterloo.ca/~cchieh/cact/c120/electrolyte.html

 

[pharmapharm]

Thanks