Any DU Chemistry students here?

[SW FL Dem]

My son just remembered he has a homework assignment due tomorrow (Ok he does has a little excuse - he's been out of school for over a week due to Hurricane Wilma).

We need help with 3 questions.

What is the mass constant of a proton?

What is the formula used to calculate the energy of a photon?

Why does a piece of iron appear red when heated sufficiently and blue at a higher temperature?

Any and all help is greatly appreciated!!

[crispini]

1. Try google!

For example, I googled Mass Constant of a proton and found this:

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/funcon.html

[SW FL Dem]

3. Thanks - did that and it didn't help

He has four possible answers and none match those on that list. I need the answer in amu's.

[crispini]

10. Ya gotta keep on searching with google.

For example I searched this basic chemistry site:

http://chemtutor.com

and found this:

"mass of a proton or neutron is 1.66 E -24 grams or one AMU, atomic mass unit."

http://chemtutor.com/struct.htm

[nashbridges]

12. he's right,

Depending on the level of homework, A photon is 1 atomic mass unit.

[SW FL Dem]

19. Yeah but we need the mass constant of a pRoton not a pHoton n/t

[nashbridges]

21. ?

Your post said photon. Consider me confused...

[SW FL Dem]

24. Sorry, it's late and I am frustrated. Thanks for all your help!

[nashbridges]

23. correction

Correction again!

1 Proton is approximately 1 a.m.u. (at least until your child gets to senior year of high school)

Photon is a a light particle/wave (debate still continues!).

And you did correctly outline the two in your first post.

-Nash

[SW FL Dem]

27. In most classes!!

Unfortunately, my kid (who at best is an above average science student) got placed in a class with all the gifted kids and with a teacher who usually teaches college classes and AP high school classes. This is his first year teaching the integrated science honors class for Freshman. Luckily, I was pretty good at science (many years ago) and I have you guys and the internet to help.

[SW FL Dem]

25. Thanks! We got a similar answer, Unfortunately

we have to choose between 1.007276 amu and 1.00865 amu. Both are close to 1 amu. I'll keep looking.

[nashbridges]

26. MSN encyclopedia

Photon mass is:
1.00728 amu

So your answer is 1.007276 since MSN rounded up.

http://encarta.msn.com/encyclopedia_761567432_2/Atom.html

Look under Section C, Atomic mass and weight. Really, this isn't in an index in the book somewhere?

[SW FL Dem]

29. No it's not.

My son spent hours looking for the answers to 45 questions, He got most of them, I was able to help with some of the others. After several frustrating hours, I thought I'd ask my fellow DUers for help. I wouldn't have asked if the answers were there. The index doesn't even list the word "mass constant" and has only 5 references to proton.

Thanks for your help. Sorry to have bothered you.

[nashbridges]

31. OK, it isn't there

But you can reference the link I just gave you and choose the closer number!

If not, I'll try and link to the reference page on the Society of Chemical Engineers web site.

[SW FL Dem]

33. We got the answer. Thanks ! n/t

[nashbridges]

32. My bad, it's a trick question

And it's really not, but your son's teacher typed exactly this into google (without quotes)

"what is the mass of a proton in amu"

Try it. It's your answer.

[Mayberry Machiavelli]

2. Umm.. does he have a book, that contains such information?

Not trying to be excessively snarky or anything, but I'm just sayin'...

[SW FL Dem]

4. No the answers aren't in his book. Trust me I have been looking

for quite a while now.

[Crazy Guggenheim]

5. For the iron it is the energy of light that is given of at that

temperature. Red is a lower temp thereby a lower frequency of light. Whereas at the higher temp the higher frequency of light which is blue.

[XemaSab]

6. the mass of a proton is 1

and the other 2 I don't know :(

[jmowreader]

7. Try this

Mass constant of a proton: http://www.mcelwee.net/html/table_of_physical_constants.html--this is a link you should save because it has LOTS of useful information in it.

Energy of a photon: http://www.science.uwaterloo.ca/~cchieh/cact/c120/emwave.html

For the third question...it's called "atomic oscillation." When you heat a piece of anything, the atoms in it increase their rate of oscillation. The hotter it is, the faster they go. When they get going fast enough, they start kicking off photons...and the item begins to glow. Red is a low-frequency color, blue is a high-frequency color. So, the hotter the item is, the higher the frequency. (With that: I've heated my fair share of iron, and I can't recall it ever getting blue. With me, it always went from red to white.)

This is going to sound like a stupid question...but are you sure this is a chemistry class? I learned this shit in physics!

[SW FL Dem]

15. Thanks.

Actually this is a freshman honors integrated science course. The teacher doesn't usually teach the freshman class, all of his other classes are AP Chemistry and AP Physics.

[Crazy Guggenheim]

8. Self Delete.

[nashbridges]

9. I can do some

1)The mass constant of a photon is just the mass of a photon:
1.6605402e-27 ±; 1.0e-33 kg. There is a measurement in electron volts (eV) but that's probably not what they are asking.

2)The formula for calculating the energy of a photon is:
E = h n

h is Planck's constant
E is energy
n is the frequency of the light

3)I'm guessing, but it's an educated guess. As the iron is heated throughout the temperature range, the photons and electrons are becoming more and more excited through the input of energy, and eventually the radiated light will move from red (low energy) to blue (high energy). Astronomers use "red" and "blue" stars to determine if a star is old (low energy) or just forming (high energy).

Hope that helps.

-Nash

[Crazy Guggenheim]

11. You're right on #1 and 3. Most likely 2 also.

[nashbridges]

13. I know I'm right on 2,

Just not sure if it's right for grade school physics!

[Crazy Guggenheim]

16. I knew I was close in my post .

[Crazy Guggenheim]

14. Nash. Off topic. But did you ever work on the show Nash Bridges?

[nashbridges]

17. no, it came about

because it really pissed people off when I killed them playing counter-strike.

However, my father LOVED Nash Bridges simply because Don Johnson was the epitome of Miami Vice.

So it's like a tribute, albeit a bizarre one.

[Crazy Guggenheim]

18. Just wondering since I was on there six times as background.

[nashbridges]

20. no shit?

My father would kiss your feet!

[Crazy Guggenheim]

22. None at all. I was also an extra in Party of Five and a few movies.

[NNadir]

28. The first two have been adequately answered, I'll help with the third.

The correct formula for question two by the way is E = hv, with Planck's constant 6.626 X 10^(-34) Joule-seconds being h and v (or nu) being the frequency of the radiation. Note that v(lamda) = c the speed of light.

The answer to the third question is related to something called blackbody radiation. As a body is heated, the atoms in the object begin to vibrate, or oscillate at higher and higher frequencies. As they do so they emit light or radiation at higher frequencies, corresponding to their vibrations. Since lower frequencies of light are red in color, as the body progressively heats up it is first red when the atoms are oscillating relatively slowly. Blue light is shorter frequencies however, so at the object gets hotter, and the atoms oscillate faster, it eventually turns blue. All of the other colors in the spectrum are intermediate.

Not just any frequencies are possible. Only certain frequencies are allowed, i.e. the atoms can only vibrate at certain distinct frequencies and not at intermediate frequencies. They are said to be quantized, they can only be multiples of certain frequencies.

The mathematical statement of how heat energy and color are related is known at the Planck distribution, and is rather complex. Within the limits of the editor here, I will attempt to post it.

p(v, T) dv = (8 (pi)hv^3/(c^3))*(dv/((exp(hv/kT)-1)

Here v is supposed to be nu, the frequency of the light, p is supposed to be the greek letter rho, representing the energy density between a particular frequency and a frequency that it infinitesimally larger, called dv (this is calculus terminology), h is again Planck's constant, k is Boltzmann's constant, and T is the temperature expressed on the Kelvin scale.

A simpler expression is available for the maximum or most intense wavelength of light we see. This is the Wien displacement law which states that the wavelength of the maximally intense light we see, times the temperature is equal to Planck's constant times the speed of light divided by the quantity of 4.965 times Boltzmann's constant.

LT = hc/4.965k where L is supposed to represent the greek letter lamda, the wavelength of the light. Lv = c. All of the the other constants are as before.

I hope this helps.

[SW FL Dem]

30. Thanks- it does

I knew this stuff many years ago. It looks like I get to learn it again :).

[nashbridges]

35. Neener Neener

Nerd! :)

I got the constant letter wrong, but the equation was still correct!

Sorry, I'm a mechie. I lose the details once the theory begins...

[Crazy Guggenheim]

34. From what I could get of the internet, the mass constant of a proton is...

1.66053873 × 10-27 kg