Pb(NO3)2 0.16M: Molar Concentration of Ions

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In summary, the conversation revolves around finding the molar concentration of each ion in a 0.16M solution of Pb(NO3)2. The discussion includes the molar mass of Pb+2 and NO3-, the equation for molarity (M = mol/L), and several attempts to solve for the concentration of each ion. The final conclusion is that the original method of multiplying 0.16M by the fractions of mass for lead and nitrate is correct, despite being deemed incorrect by the teacher.
  • #1
AJKing
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Homework Statement



What molar concentration of each ion appear in 0.16M Pb(NO3)2?

*Note* The title incorrectly says "moles".

Homework Equations



M = mol/L

The Attempt at a Solution



My teacher tells me this is wrong, but I can't see my fault:

Molar Mass of Pb+2 = 207.20g
Molar Mass of NO3- = 124.02g

[itex]\frac{x}{1L} = 0.16M[/itex]

[itex]x = 0.16mol[/itex]

[itex]0.16mol = \frac{y*1mol}{331.22g}[/itex]

[itex]y = 53g[/itex][itex]Pb: 53g * \frac{207.20g}{331.22g} = 33g[/itex]

[itex]\frac{33g}{331.22g} = 0.10mol[/itex][itex]NO_{3}: 53g *\frac{124.02}{331.22g} = 20g[/itex]

[itex]\frac{20g}{331.22g} = 0.06mol[/itex][itex]Pb = \frac{0.10mol}{1L} = 0.10M[/itex]

[itex]NO_{3} = \frac{0.06mol}{1L} = 0.06M[/itex]

Any ideas where I messed up?
Or if I did?
 
Last edited:
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  • #2
I would also like to say that in my first attempt to solve this, I simply multiplied 0.16M by the fractions of mass for lead and nitrate and got the same answers.

That was the "incorrect" version. This is my third attempt, with the same results.
 

1. What is the molar concentration of Pb(NO3)2 0.16M?

The molar concentration of Pb(NO3)2 0.16M is 0.16 moles per liter (mol/L). This means that for every liter of solution, there are 0.16 moles of Pb(NO3)2.

2. How is the molar concentration of ions calculated?

The molar concentration of ions is calculated by dividing the moles of the ion by the volume of the solution in liters. In the case of Pb(NO3)2, the molar concentration of ions would be 0.16M because each molecule of Pb(NO3)2 dissociates into one Pb2+ ion and two NO3- ions, resulting in a total of 0.16 moles of ions per liter of solution.

3. Why is molar concentration important in chemistry?

Molar concentration is important in chemistry because it is a measure of the amount of substance present in a given volume of solution. This allows scientists to accurately measure and compare the concentration of different substances in solutions, which is crucial in many chemical reactions and experiments.

4. How does the molar concentration of ions affect the properties of a solution?

The molar concentration of ions can greatly affect the properties of a solution, such as its conductivity, pH, and reactivity. For example, a higher molar concentration of ions can result in a more conductive solution, while a lower concentration may result in a less reactive solution.

5. How can the molar concentration of ions be changed?

The molar concentration of ions can be changed by altering the amount of solute or the volume of the solution. Adding more solute or decreasing the volume of the solution will increase the molar concentration of ions, while decreasing the amount of solute or increasing the volume will decrease the molar concentration.

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