Chemistry
posted by Anon on .
a)The Young's modulus for a material is 5.0*10^10 N/m2. The material is stretched to a strain of 4.0*10^3. How much elastic energy will be expended? (Express your answer in J/m3)
Knowing that the energy associated with the formation of 1 mole of vacancies in copper (Cu) is 104 kJ, determine the vacancy density (nv/cm3) in Cu at 1366 K. Assume the preexponential factor is one.
Can someone help me with those questions? I can help with the rest!!

Hi I am working on it. Meanwhile Can you help me with the 3th and 4th questions about the graphics?

3//1.13 ev
semiconductor
4//4th option
ntype
4th option
intrinsic 
Hi can you help me with first part of 1st question .
answer of 2nd part is 189 
can u help me with the formula of Cu bsc me temperature is 1056 plssssssssssssssssss help

Determine for solid manganese (Mn) the following:
What is the atomic density (atoms/m) along the [110] direction of the Mn crystal?
What are the number of nearest neighbors around an atom in the Mn crystal?
Calculate the interplanar spacing (m) between {220} planes in the Mn crystal. 
if someone help with those questions I'll post all the rest of answers

ΔHv=104,000J/6.02×10^23=1,7276*10^19
nv/Ns=e^{(1.7276*10^19)/[(1.381×10^−23)*(1366)]}=Result
Use the result to substitute to:
nv/Ns*ρ*Avogadro number/Mw(Cu)
=
nv/Ns(result from above) * 8.94*( 6.02*10^23/63.546) 
watch out that the formula is negative (on e), so it should be in the range of x*10^4 or 10^5!
And note, that I can not give you the right answer as I succeeded only on my third attempt :)
I need help with 11 and 12. 
1 7.36e2
189
2metal
Solid hydrogen has a half filled sband
insulator
Solid helium has a filled sband
31.13
semiconductor
4Ionization of phosphorus requires some minimum temperature
n_type
The concentration of conduction electrons is fixed by the concetration of phosphorus
intrinsic
52.44e9
8
1.025e10
61.8e10
7BCC
3.172
1.37
8 HELP !!!!!!!!!!!!!!!!!!!!!!!!!!
9(for energy 104 kj and vacancy density 1366 K) 8924699659276140118.9689358889623
10sample A
sample B
sample B
sample D
sample C
sample C
11increase air flow on the bottom array
122.773e2
132.58e16 
The Young's modulus for a material is 8.0 x 1010 N/m2. The material is stretched to a strain of 9.0 x 103. How much elastic energy will be expended? (Express your answer in J/m3).
Answer: 3240000 
@Drew can you give me the formula?

Ev= elastic strain energy per unit vol=?
Ev=(1/2)*Ey*E2(square)
Ey= 8.0*10e+10 N/m2
E= 9.0e3 so square >
E2= 8.1e5 
thanks

Did you find the last quetion of homework 11?

No, I didn't find that answer.

can u help me with the formula of Cu bsc me temperature is 1056 plssssssssssssssssss help

nv/Ns=A*e(Hv/(KT))
K=1.381E23
Hv= 104000/6.023e+23
A=1
vacancy density=(nv/Ns)*Cu density*(6.023e+23/Cu atomic weight) 
thnks @ Drew :)

Thanks Anon and Drew for the formula, I have other exams to prepare for so this was a life saver, I appreciate it truly. I however do not know how to calculate my result using exponents so can someone please solve for T=1373 K? I would be forever grateful. If I find the answers for the last few questions I will be sure to share it.

oops I reset it, new value of T is 1091 K somebody help please :'(

Never mind guys, alphawolfram did it for me :)~ any luck with the last three questions? Today is the deadline!