# chemistry

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Which of the following diatomic species are paramagnetic and which are diamagnetic? A blank molecular orbital diagram (Part B 1 figure) has been provided to help you.
Drag the formulas to the appropriate magnetic bin :C2^2+,Li2-,B2^2-

• chemistry -

Step 1. Write the electron configuration. I'll do the first one.
C^+2 =
1s2 2s2 2p2 is the neutral atom.
+2 ion is 1s2 2s2.

Step 2. With a 1s2 2s2 configuration, an remembering Hund's rule (of maximum multiplicity) which means the electrons don't pair unless they must, we know the 2s orbital is full and both electrons are paired; therefore, not paramagnetic. You must have an unpaired electron to have a paramagnetic substance.
I'll leave the others for you.

• chemistry -

The average bond enthalpy for a C=C double bond is 614kj/mol and that of a C-C single bond is 348 kj/mol . Estimate the energy needed to break the bond in 2-butene.

i got it wrong what i did was i took :pi bond = 614-346
but it said that i got J/mol instead of kj .. i don't know how i got that
plz help?

• chemistry -

What is the longest wavelength of light that will provide photons of sufficient energy to break the pi bond and cause the isomerization?

the energy needed to break the bond is 4.42*10^-19

• chemistry -

nevermind i got it

• chemistry -

• chemistry -

The equation is energy = frequency x Planck's constant (E = ν x h) , and frequency = speed of light / wavelength (ν = C / λ), so the equation you'll be working with is
E = (C / λ) x h

C (speed of light) = 2.998 x 10^8 m/s
h (Planck's constant) = 6.626 x 10^-34 J•s
λ = unknown wavelength
E (energy) = 4.42 x 10^-19 J

4.42 x 10^-19 J = [(2.998 x 10^8 m/s) / λ] x (6.626 x 10^-34 J•s)
4.42 x 10^-19 J = (2.998 x 10^8 m/s x 6.626 x 10^-34 J•s) / λ
(4.42 x 10^-19 J) λ = (2.998 x 10^8 m/s x 6.626 x 10^-34 J•s)
λ = (2.998 x 10^8 m/s x 6.626 x 10^-34 J•s) / (4.42 x 10^-19 J)

Type everything on the right into a calculator and cancel out the labels, and you would get about 4.49 x 10^-7 m, or 449 nm. That's a blue-ish to indigo light.

• chemistry -

B2^2- di
other two para