[xstrae]

Hi,

1. What is the spin magnetic moment of Ni²⁺ ion? [solution: 2.828BM]

I can see that Ni²⁺ has two unpaired electrons. Is there any specific formula to calculate the spin magnetic moment?  Also, whats a BM? I have never come across such units.

2. One mole of a gas A occupies 1.2L. Under same conditions, one mole of an ideal gas occupies 1.1 litres. Which of the following statements are correct?

(A) In A, repulsive forces always dominate over attractive forces.
(B) Compressibility factor for A is more than one under the conditions given.
(C) The value of 'a' (which is the pressure correction in the ideal gasl law) for the gas A is less than one.
(D) Gas A is easily liquifiable in comparable to ideal gas.

Here is what I thought:
Since gas A occupies a greater volume than an ideal gas under similar conditions, the forces of attraction between molecules in A is less than the forces of attractiction in the ideal gas. Since the volume is higher, repulsive forces must dominate over attractive forces. so (A) is correct.

Compressibility factor = volume of gas A/volume of ideal gas > 1 so (B) applies too.

is this correct? thanks for your time.

[Dan]

1. What is the spin magnetic moment of Ni²⁺ ion? [solution: 2.828BM]

I can see that Ni²⁺ has two unpaired electrons. Is there any specific formula to calculate the spin magnetic moment?  Also, whats a BM? I have never come across such units.

Yes. Have you actually looked this up in a book? I sometimes get the impression that you are asking for answers before doing any of your own research. It's definately in Shriver & Atkins (inorganic chemistry), and probably in every inorg textbook ever written.

BM is probably the Bohr magneton, usually written ?_B in my experience

[xstrae]

ok I looked it up. spin magnetic moment = [n(n+2)]^1/2BM where n is the number of unpaired electrons. thanks.

and is my thinking correct for the 2nd problem?

[Dan]

yeah I think 2 is fine

[xstrae]

allright.. I just asked that because my book said the correct answer is only (B). anyway thanks

[Dan]

oh, yeah I missed the "always"