Saturday, 27 October 2007 - 1:33 PM EDT

I also need part b of the tire pressure, and part c of the scuba diver. 

the conceptual are:

Incorrect -- an aluminum plate has a hole cut in the center. when the plate is heated, the hole gets smaller.

Correct -- when the pendulum of a grandfather clock is heated, the clock runs more slowly

Incorrect -- cold objects do not radiate heat energy

Incorrect -- when the celsius temperature doubles, the fahrenheit temperature doubles

Incorrect -- in a bimetalic strip of brass and copper which curls when heated, the brass is on the inside of the curve.

incorrect -- when heat is added to a system, the temperature must rise.

root-mean-square:

the equation is: Vrms = square root( 3kT/M) .  k is a constant 1.38E-23. the temperature is not given, but the rms of O2 is given, so you need to use that first to determine the temperature.  once you solve for the temperature, it is the same for He, so thats the answer to part B. then you plug it into the equation and solve for Vrms of He, and thats the answer to part A. 

Saturday, 27 October 2007 - 6:35 PM EDT

I need help with parts a, b, d of scuba diver

Part c of scuba diver

use the equation V rms = squ. root 3kT/m for both helium and oxygen

once you have the V's, use the equation KE=1/2mv^2 for both helium and oxygen. For this equation, use the V's from the previous equation. Once you have the KE for both helium and oxygen, do the ratio of the KE. My ratio was 1.

Saturday, 27 October 2007 - 7:28 PM EDT

I need help with the tire pressure part B

Sunday, 28 October 2007 - 12:34 PM EDT

Can someone help me with the constant volume problem?

Sunday, 28 October 2007 - 12:47 PM EDT

thanks for scuba part c!! heres a,b&d:

a: take the given volume and divide by 2 b/c O2 makes up half the volume. then divide by 1000cm^3 to change the units from cm^3 to L. then use equation PV = nRT , which rearranges to n = PV/RT b/c you are solving for n. remember to add 1 atm to the given pressure b/c it tells you the gauge pressure. once you have n, multiply by avogadros # (6.02E23). 

b: the answer is the same as A, because the conditions are the same.

d: use Vrms = square root( 3kT/m)  for both He and O2, then take the ratio of He over O2. (the m of He is 6.64E-27, and for O2 m = 5.31E-26)  

Sunday, 28 October 2007 - 12:51 PM EDT

constant volume: 

P(final) divided by P(initial) 

Sunday, 28 October 2007 - 2:39 PM EDT

Hey i was wondering if anyone had bridge expansion, rivets, or STP? I have all the other ones so if anyone needs the rest just let me know! Those are the only ones i can get!

Sunday, 28 October 2007 - 2:41 PM EDT

question 1 where it asks for the numerical value where celsius and farhenit are same is 233k. Incase anyone needed it! 

Sunday, 28 October 2007 - 3:33 PM EDT

Hey guys! I figured the Bridge expansion and rivets problems out! But does anyone have how to do the STP problem? I have tried many things but cannot figure it out! Thanks

Sunday, 28 October 2007 - 3:34 PM EDT

Hey guys! I figured the Bridge expansion and rivets problems out! But does anyone have how to do the STP problem? I have tried many things but cannot figure it out! Thanks

Sunday, 28 October 2007 - 5:21 PM EDT

hey ive been trying to do par a for scuba diver and im still not getting right

Sunday, 28 October 2007 - 6:05 PM EDT

the rivets, its just delta D Divided by steel coefficient X original length.

for the volume, use the one given divided by two. answer is same for gelium and oxygen

Sunday, 28 October 2007 - 6:10 PM EDT

for stp problem, change the ass to grams and use the mass of the gas given, eg Oxygen is 16 so O2 is 32. Divide by the mass to get the mol them multiply by the volume of 1 mol of any gas....a constant number. (22.4 L)

bridge expansion. get the change in both temperatures then subtract the highest from the lowest. dont forget to change T to absolute

Sunday, 28 October 2007 - 7:38 PM EDT

Will someone help me with tire pressure part B please. thanks

Sunday, 28 October 2007 - 10:01 PM EDT

tire pressure part b:

use equation P1*T2/T1(percent) . for P1 you use the same pressure from part a (with 101 Kpa added.) the temps are the same, and convert your percent to a decimal -- mine was 9% so .09 -- then add 1.00 because the volume is INCREASED -- so 1.09. once you get the new pressure, remember to subtract 101 to get the final answer

Monday, 29 October 2007 - 4:16 PM EDT

Does anyone know how to do part a for the scuba diver and part a for the tire pressure. I'm trying what was written before but its not working

Monday, 29 October 2007 - 7:32 PM EDT

I am still having trouble with tire pressure part B and the rivets problem. I have tried the previous ways that have been posted but it is still not working

Monday, 29 October 2007 - 9:11 PM EDT

yeah im having trouble with it too....i only have one more try...can neone help?

Monday, 29 October 2007 - 9:45 PM EDT

I've tried to post help for tire pressure part B before, so I hope this is clearer. for part A you had to add 101 kPa to the given pressure, and in part B you use it again. the equation for part B is (P1T2)/T1(percent in decimal +1.00) .  my given pressure was 182, so I added 101 and got 283. T2 is the second temp given, but in K. (49C = 322K). my first temp was 1C, so 274K. you take whatever percent your gauge has increased by, mine was 9%, and make it 100% plus that, because the pressure has increased from original at 100% an extra 9% -- thus 109%, or 1.09. all in all this is what I did: (283kPa*322K)/(274K*1.09) . once you get that # (305.12 in my case), subtract the 101 kPa again, so that the answer is in gauge pressure. so my answer was 204.12

I know this is wordy, but I hope it explains things better 

Monday, 29 October 2007 - 10:46 PM EDT

I have finally gotten the tire pressure part b but I am on my 7th try for the rivets and it is not working........... please help

Monday, 29 October 2007 - 10:56 PM EDT

Hey can anyone help me out with tire pressure A.. I thought I was doing the right eqn but its not working out

Monday, 29 October 2007 - 11:07 PM EDT

rivets:

use deltaT = (deltaL)/(alpha*Lo)    delta T is what you are solving for, and delta L is the difference in sizes. (make sure when you take the difference it is negative because you are shrinking it by that much). the alpha of steel is 12E-6. Lo is the size that needs to be changed (the rivet).  once you get that answer add 20C because that is the temp you are cooling to. make sure your answer is negative BEFORE you add 20deg. -137+20 is different from 137+20 then making it negative (this is where I messed up...) 

Tuesday, 30 October 2007 - 1:15 PM EDT

what are the units for part b of the tire pressure and how did you get part a?? please help =) 

Tuesday, 30 October 2007 - 2:20 PM EDT

Can someone explain part b of the stp and how to do part a of the tire pressure? thanks

Tuesday, 30 October 2007 - 3:24 PM EDT

Ive followed what people have posted about the Scuba Diver for part a and b..and i still cant get the answer. I only have 2 trys left....can someone help?

Tuesday, 30 October 2007 - 3:35 PM EDT

can someone help with part 1 of tire pressure and stp?

Tuesday, 30 October 2007 - 4:14 PM EDT

I can't get the scuba diver either...any help at all would be great. 

Tuesday, 30 October 2007 - 4:37 PM EDT

for some reason i keep gettin the root mean square problem wrong i am using Vrms= sqr(3kT/m) but i can't seem to get the right aanswer...any suggestions?

Tuesday, 30 October 2007 - 4:59 PM EDT

Did you solve for the temerature using the root mean square of O2 first? Thats the first step then you just plug in the numbers...check to make sure you are doing everything right on the calculator. Sometimes the mistakes we make are the simple ones

Tuesday, 30 October 2007 - 5:28 PM EDT

got every problem but the scuba diver for pt A,B, D, anyone willing to trade?!?

Tuesday, 30 October 2007 - 5:49 PM EDT

can anyone help with stp i only have 2 tries

Tuesday, 30 October 2007 - 7:07 PM EDT

STP: convert given kg to g, then divide by 2*16 . --you multiply it by 2 because you have 2 O's. the answer you get now is your moles of O2, and you multiply this by 22.4L/mol (its a constant) and that gives you the answer to part A, in L. 

B: do the same thing as part A, but add the new pressure with the old pressure in the numerator. still divide by 32. this is your new moles. then use  equation PV = nRT, solving for P. n is what you just solved for, R is a constant and T is 273 K, V is the answer from part A.

Tuesday, 30 October 2007 - 7:09 PM EDT

can anyone please explain tire pressure a.. i only have 2 more tries left... I also jus need scuba diver a and b and the stp problem ...please help!

Tuesday, 30 October 2007 - 7:23 PM EDT

Tire Pressure a:

add 101 to given Pressure = X

divide X by lowest given temperature (remember to convert to K by adding 273) = Y

multiply Y by highest given temperature (remember to convert to K by adding 273) = Z

subtract 101 from Z = ANSWER!

 Lisa did a great job explaning the STP one.  Look Up!

Tuesday, 30 October 2007 - 7:26 PM EDT

scuba diver part b is the same for everyone which is 1. let me know if it helps

Tuesday, 30 October 2007 - 7:28 PM EDT

NOT PART B, PART C IS 1

Tuesday, 30 October 2007 - 7:31 PM EDT

Tire pressure a is the exact same problem as on page 366.  Hope this helps!

Tuesday, 30 October 2007 - 7:41 PM EDT

i hate to ask, but what are the units for STP part b?

Tuesday, 30 October 2007 - 7:46 PM EDT

nevermind, i figured out the units for part b of STP. they're kPa.

Tuesday, 30 October 2007 - 7:52 PM EDT

For the Root Mean problem I dont know how to solve for T. I know the equation is vrms= square root (3kT/M) but how do you get T. Maybe I'm rearranging it wrong. What should it be to rearrange for T?

Tuesday, 30 October 2007 - 8:04 PM EDT

can someone please help with the Scuba question for A&B. I've looked at the solutions posted earlier and I cant figure it out from that.

Tuesday, 30 October 2007 - 8:09 PM EDT

can someone help with part B of the STP problem??? Its the last one i need =) please help! 

Tuesday, 30 October 2007 - 8:10 PM EDT

For the scuba diver part a and b you after you add 1 to your given atm, you have to convert it into pKa by multiplying the number by 101.3pKa.. hope that helps!! Can someone help with part b of the stp?? Im doing the work from above and cant get the right answer..

Tuesday, 30 October 2007 - 11:49 PM EDT

lisa i think we all love you

Tuesday, 30 October 2007 - 11:58 PM EDT

can someone please tell me how to solve the bridge expansion problem

Tuesday, 30 October 2007 - 11:59 PM EDT

can someone please tell me how to solve the bridge expansion problem