Molecular weight of lead(ii) nitrate Pb(NO_3)_2

In summary, the conversation discusses a discrepancy in the calculation of the molecular weight of Pb(NO_3)_2 between the book Analytical Chemistry 7th edition and various online sources. After further discussion and investigation, it is determined that the book contains an error in the molar mass used, resulting in a difference of 48 g/mol. The individual expresses gratitude for the clarification and mentions the possibility of other mistakes in the book.
  • #1
Paul Black
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Hello everyone
I am trying to solve the following question from the book Analytical Chemistry 7th edition by Gard D. Christian - Page 164 Example 5.17
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My problem is when I calculate the molecular weight of Pb(NO_3)_2 I get 331.2 g/mol but in the book they get 283.2 g/mol . Could you explain to me where they get this number. So instead of getting 0.137 g as last result, I get 0.16 g.

Also googling the question always gets me the same solution.
 
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  • #2
Paul Black said:
when I calculate the molecular weight of Pb(NO_3)_2 I get 331.2 g/mol

That's what I got as well, book is wrong.
 
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Likes HAYAO, jim mcnamara and Paul Black
  • #3
First time I see an error in a book.
So in that case all the internet pages that have the same question+solution made the same mistake. Do they just copy past ?
 
  • #4
Paul Black said:
First time I see an error in a book.

Lucky you.

So in that case all the internet pages that have the same question+solution made the same mistake. Do they just copy past ?

Apparently.

The molar mass they used is off by 48, which is exactly three oxygen atoms, as if they had calculated molar mass for PbN2O3.
 
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Likes HAYAO and Paul Black
  • #5
Thank you for your help
Will see if this book has more mistakes.
 

FAQ: Molecular weight of lead(ii) nitrate Pb(NO_3)_2

What is the molecular weight of lead(ii) nitrate?

The molecular weight of lead(ii) nitrate, also known as Pb(NO3)2, is approximately 331.21 grams per mole. This can also be written as g/mol.

How is the molecular weight of lead(ii) nitrate calculated?

The molecular weight of a compound is calculated by adding the atomic weights of each element present in the compound. In the case of lead(ii) nitrate, the atomic weight of lead (Pb) is 207.2 g/mol and the atomic weight of nitrogen (N) is 14.01 g/mol. Since there are two nitrate ions (NO3) in the compound, the atomic weight of oxygen (O), which is 16 g/mol, is multiplied by 6. Therefore, the calculation for the molecular weight of Pb(NO3)2 is (207.2 + 2(14.01) + 6(16)) = 331.21 g/mol.

Why is it important to know the molecular weight of lead(ii) nitrate?

The molecular weight of a compound is important for various reasons. It is used in stoichiometric calculations to determine the amount of reactants needed to produce a certain amount of product. It is also used in determining the concentration of a solution and in understanding the physical and chemical properties of a compound.

Can the molecular weight of lead(ii) nitrate vary?

No, the molecular weight of a compound like lead(ii) nitrate is a constant value and does not vary. This is because the atomic weights of the elements present in the compound are fixed values determined by the atomic structure of the elements.

What units are used to express the molecular weight of lead(ii) nitrate?

The molecular weight of lead(ii) nitrate is expressed in grams per mole (g/mol). This unit is commonly used in chemistry to represent the mass of a substance in relation to the number of particles present.

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