Calculate the mass of NaCl needed to bring sodium concentration to 0.139 M?

In summary: PIn summary, the conversation discusses how to calculate the amount of sodium chloride needed to bring the sodium ion concentration in the blood up to a desired level. Using the atomic weight of Na, the mass of sodium in the blood is determined. Then, by finding the ratio of mass in NaCl, the mass of Cl in NaCl can be calculated. Finally, the total mass of NaCl needed is calculated to be 6.6g. There was also a correction made to the atomic weight of Na, which is actually 23g instead of 230g.
  • #1
Modrisco
8
0
A person suffering from Hypothermia has a sodium ion concentration in the blood of 0.114 M and a total blood volume of 5.1 L. What mass of sodium chloride needs to be added to the blood to bring sodium ion concentration up to 0.139 M? (assuming no change in blood volume)

--------------------------------------…

Atomic weight of Na: 230 g

Mass of sodium in blood:
230 x 0.114 M = 26.22 g

Mass of sodium needed:
230 x 0.139 = 32.97
32.97 - 26.22 = 5.72 g

5.72 g of sodium needed

Ratio of mass in NaCl
Mass of Cl : Mass of Nacl
35.453 g : 230 g
1 : 6.49

Mass of Cl in NaCl when Na is 5.72 g:

230/35.453 = 5.72/x
230x = 5.72(35.453)
230x = 202.79
x = 202.79/230
x = 0.88g


Mass of NaCl needed:
0.88g + 5.72g
= 6.6 g



Mass of NaCl needed 6.6g


Is this correct?
 
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  • #2
Looks good. Although, I would have done the last calculation slightly differently:
Mass of Cl : Mass of Nacl
35.453 g : 230 g

so the total mass of (one mol of) NaCl is 35.453+ 230= 265.453 g. That is a ratio of NaCl to Na of 265.453/230= 1.154 so the the total mass of NaCl to produce 5.72 g of sodium is (1.154)(5.72)= 6.6 g of NaCl. exactly what you got.
 
  • #3
Thank you very much:) I prefer your way haha

If you're a yahoo question answerer, you can copy and paste that answer to the same question that I asked 3 times (no one wanted to answer) and I will give you best answer for each one:)
thank you

Here is the links to the same question:

http://uk.answers.yahoo.com/questio...U3.P7tYgBgx.;_ylv=3?qid=20120430180751AAuGj9N

http://uk.answers.yahoo.com/questio...DhT6K4kgBgx.;_ylv=3?qid=20120430133241AAhfri9

http://uk.answers.yahoo.com/question/index;_ylt=AiO70AMxfXqdmWoboJrzBPkgBgx.;_ylv=3?qid=20120430131115AA32Mjs [Broken]


A lannister, always pays his debts.
 
Last edited by a moderator:
  • #4
Just realized I made a massive error in the atomic weight of Na, it's 23g not 230g hahaha
 
  • #5
Modrisco said:
Just realized I made a massive error in the atomic weight of Na, it's 23g not 230g hahaha

That was the first thing that caught my eye.
 

1. How do you calculate the mass of NaCl needed for a specific sodium concentration?

The formula for calculating the mass of NaCl needed is:
Mass of NaCl (g) = (Desired concentration (M) x Volume of solution (L) x Molecular weight of NaCl (g/mol)) ÷ 1000

2. What is the molecular weight of NaCl?

The molecular weight of NaCl is 58.44 g/mol. This is calculated by adding the atomic weights of sodium (22.99 g/mol) and chlorine (35.45 g/mol).

3. How do you convert Molarity to moles?

To convert from Molarity to moles, you can use the formula:
Moles = Molarity (M) x Volume of solution (L)

4. What is the volume of solution needed for this calculation?

The volume of solution needed depends on the desired concentration and the amount of NaCl being added. This can be calculated by rearranging the formula:
Volume of solution (L) = (Mass of NaCl (g) x 1000) ÷ (Desired concentration (M) x Molecular weight of NaCl (g/mol))

5. What is the significance of bringing the sodium concentration to 0.139 M?

The significance of bringing the sodium concentration to 0.139 M may vary depending on the specific experiment or application. However, maintaining a specific concentration of sodium allows for better control and consistency in experiments involving NaCl solutions. Additionally, certain biological processes and organisms may require a specific sodium concentration for proper functioning.

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