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Posted: 9/8/2010 3:42:51 PM EDT
My step daughter asked me for help with a homework question, I am stumped. Here goes.

Williams Freight Company recieves a truckload of cotton that contained mothballs to protect it from insects. When the sealed container left Denver, Colorado it weighed 100 kg. When it arrived in Baltimore, Maryland its mass was 99 kg. Explain the loss in mass.

Link Posted: 9/8/2010 3:44:32 PM EDT
The mothballs turned into a gas and were dispersed, would be my guess.
Link Posted: 9/8/2010 3:44:44 PM EDT
Difference in air density between Denver and Baltimore?
Link Posted: 9/8/2010 3:45:27 PM EDT
Mothballs evaporate (sublimate?).

1 Kg of mothballs (Naphthalene) changed from a solid to a vapor, decreasing the weight.
Link Posted: 9/8/2010 3:45:35 PM EDT
Sublimation.
Link Posted: 9/8/2010 3:45:43 PM EDT
When did they start growing cotton in Denver?
Link Posted: 9/8/2010 3:45:46 PM EDT
Originally Posted By capnrob97:
Difference in air density between Denver and Baltimore?


This, I'm geussing.
Link Posted: 9/8/2010 3:47:11 PM EDT
[Last Edit: 9/8/2010 3:48:14 PM EDT by desertmoon]

Originally Posted By Izzman:
The mothballs turned into a gas and were dispersed, would be my guess.




Link Posted: 9/8/2010 3:47:39 PM EDT
A few moths were castrated along the way

Rimshot

Posted Via AR15.Com Mobile
Link Posted: 9/8/2010 3:48:58 PM EDT
Denver is at 5280 ft MSL, Baltimore is effectively 0 ft MSL


Link Posted: 9/8/2010 3:48:59 PM EDT
Originally Posted By electrojk:
When did they start growing cotton in Denver?



Dude. Its a high school science question. I was too dumb to answer. I asked arfcom. The fuck
Link Posted: 9/8/2010 3:49:41 PM EDT
How'd they get their little legs apart?

Evaporation.
Link Posted: 9/8/2010 3:50:48 PM EDT
I get to ask:

Don't moths go after wool and not cotton

Link Posted: 9/8/2010 3:52:28 PM EDT
Originally Posted By GiggleSmith:
I get to ask:

Don't moths go after wool and not cotton



These are cotton weevils masquerading as moths.
Link Posted: 9/8/2010 3:53:16 PM EDT
The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton?
Link Posted: 9/8/2010 3:54:22 PM EDT
[Last Edit: 9/8/2010 3:57:11 PM EDT by Meademac]
Could be sublimation of the moth balls or moisture loss of cotton?
Probably looking for sublimation of MB.

====================================================
Reread...sealed container, was the cotton weighed when removed
or entire container with sealed contents?
Link Posted: 9/8/2010 3:56:12 PM EDT

Originally Posted By colklink:
My step daughter asked me for help with a homework question, I am stumped. Here goes.

Williams Freight Company recieves a truckload of cotton that contained mothballs to protect it from insects. When the sealed container left Denver, Colorado it weighed 100 kg. When it arrived in Baltimore, Maryland its mass was 99 kg. Explain the loss in mass.


There was 1Kg of insects in there and the scrammed.

Link Posted: 9/8/2010 3:56:28 PM EDT
Originally Posted By NoahFN:
Sublimation.


This would normally be the correct answer. Sublimation is evaporation of a solid directly to gas. However, the fact that it is a sealed box in the problem is throwing me for a loop. If it's hermetically sealed, there is no way for the evaporated mass to escazpe the box, so it would have the same mass as it started out with.
Link Posted: 9/8/2010 3:57:04 PM EDT
State Patrol in a Rhode Island weigh station noticed a light out, and taxed the driver a little of his load.

Or, driver had some "fall off the truck".
Link Posted: 9/8/2010 3:57:27 PM EDT
Originally Posted By Meademac:
Could be sublimation of the moth balls or moisture loss of cotton?
Probably looking for sublimation of MB.


I think you are right. She just aksed me a question on the conservation of mass, it had to do with evaporation. I love having to figure out stuff after not having sat in the class

Link Posted: 9/8/2010 3:57:32 PM EDT

Originally Posted By Gulbrandr2:
Originally Posted By capnrob97:
Difference in air density between Denver and Baltimore?


This, I'm geussing.

Shouldn't effect "mass". Mass is the same at sea level and in zero gravity.
Link Posted: 9/8/2010 3:58:49 PM EDT
Some of the product "fell off" the truck.
Link Posted: 9/8/2010 3:58:51 PM EDT
The correct answer is that the cotton settled, like corn flakes do in the box. Hence, the extra empty space in the box.
Link Posted: 9/8/2010 3:59:30 PM EDT

Originally Posted By Partisan:
Originally Posted By GiggleSmith:
I get to ask:

Don't moths go after wool and not cotton

These are cotton weevils masquerading as moths.
Fair enough.
Link Posted: 9/8/2010 3:59:50 PM EDT

Originally Posted By Ponyboy:
The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton?

Union Labor.

Link Posted: 9/8/2010 4:00:04 PM EDT
Think it would be more of the cotton drying out than the naptholene evaporating.
Link Posted: 9/8/2010 4:01:39 PM EDT
Scales are not calibrated to 100% of each other.

I have no idea.

Link Posted: 9/8/2010 4:02:00 PM EDT
Originally Posted By Mazeman:

Originally Posted By Gulbrandr2:
Originally Posted By capnrob97:
Difference in air density between Denver and Baltimore?


This, I'm geussing.

Shouldn't effect "mass". Mass is the same at sea level and in zero gravity.


Mass is constant but weight will vary based on location. Gravity is not constant everywhere.
Link Posted: 9/8/2010 4:02:53 PM EDT
Originally Posted By JohnnyP:
Think it would be more of the cotton drying out than the naptholene evaporating.


You may be right. High school science was a long time ago

Thanks for all the replies btw.

Link Posted: 9/8/2010 4:03:55 PM EDT
Tell her to look in the text for the last chapter at highlighted key words.

My guess is that sublimation is one of them, and is the answer, don't over think it.
Link Posted: 9/8/2010 4:04:13 PM EDT
[Last Edit: 9/8/2010 4:04:49 PM EDT by California_Kid]
It's interesting that one figure is expressed as mass, and the other as weight. The gravitational pull in Baltimore is higher than it is in Denver, but the difference is negligible.

The change in mass is due to sublimation of part of the mothballs.
Link Posted: 9/8/2010 4:06:00 PM EDT

Originally Posted By Partisan:
Originally Posted By Mazeman:

Originally Posted By Gulbrandr2:
Originally Posted By capnrob97:
Difference in air density between Denver and Baltimore?


This, I'm geussing.

Shouldn't effect "mass". Mass is the same at sea level and in zero gravity.


Mass is constant but weight will vary based on location. Gravity is not constant everywhere.
Right. But the problem used the term "mass" as the thing that decreased.

Another likely possibility is a confused teacher.

Link Posted: 9/8/2010 4:07:27 PM EDT
depending on what "sealed container" means, the pressure inside would still be the same as it was in Denver (ie less than air pressure)
Link Posted: 9/8/2010 4:08:06 PM EDT

Originally Posted By Ponyboy:
The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton?

It was a Dodge; they were afraid to stress the transmission.
Link Posted: 9/8/2010 4:09:04 PM EDT
Originally Posted By California_Kid:
It's interesting that one figure is expressed as mass, and the other as weight. The gravitational pull in Baltimore is higher than it is in Denver, but the difference is negligible.

The change in mass is due to sublimation of part of the mothballs.



Why would the gravitational pull in Baltimore be more than in Denver?

Link Posted: 9/8/2010 4:10:09 PM EDT

Originally Posted By Ponyboy:
Originally Posted By California_Kid:
It's interesting that one figure is expressed as mass, and the other as weight. The gravitational pull in Baltimore is higher than it is in Denver, but the difference is negligible.

The change in mass is due to sublimation of part of the mothballs.



Why would the gravitational pull in Baltimore be more than in Denver?


Gravity decreases with altitude.
Link Posted: 9/8/2010 4:10:32 PM EDT
Illegals.

Link Posted: 9/8/2010 4:11:50 PM EDT
Mary has 3 type of fish conks. Each conk consists of 7 spikes. Each spike has 30 layers. If Kim decides to give Bill 4 conks and Tom has already recived 2 conks from his car dealer, what city does Mary live in.
Link Posted: 9/8/2010 4:12:16 PM EDT
Originally Posted By capnrob97:

Originally Posted By Ponyboy:
Originally Posted By California_Kid:
It's interesting that one figure is expressed as mass, and the other as weight. The gravitational pull in Baltimore is higher than it is in Denver, but the difference is negligible.

The change in mass is due to sublimation of part of the mothballs.



Why would the gravitational pull in Baltimore be more than in Denver?


Gravity decreases with altitude.



Gravity increases with mass and there is more mass beneath you in Denver than in Baltimore. I'm pretty sure gravity would be stronger in Denver.

Link Posted: 9/8/2010 4:12:30 PM EDT
Originally Posted By GoGop:

Originally Posted By Ponyboy:
The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton?

It was a Dodge; they were afraid to stress the transmission.


Let's assume the teacher wasn't going for the gravity/mass/weight thing, because the question was worded incorrectly as it pertains to that issue.

Sublimation.
Link Posted: 9/8/2010 4:12:41 PM EDT
Originally Posted By California_Kid:
It's interesting that one figure is expressed as mass, and the other as weight. The gravitational pull in Baltimore is higher than it is in Denver, but the difference is negligible.

The change in mass is due to sublimation of part of the mothballs.



I noticed that too, but I did type it directly from the paper. Right now I am trying to help her with her business communications homework. I know less about that than science.



Link Posted: 9/8/2010 4:12:52 PM EDT
[Last Edit: 9/8/2010 4:13:27 PM EDT by JmPnTX]
Mothballs sublimated (went from solid to gas). They are volatile.

from Wiki:

Naphthalene, also known as naphthalin, bicyclo[4.4.0]deca-1,3,5,7,9-pentene or antimite is a crystalline, aromatic, white, solid hydrocarbon with formula C10H8 and the structure of two fused benzene rings. It is best known as the traditional, primary ingredient of mothballs. It is volatile, forming a flammable vapor, and readily sublimes at room temperature, producing a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass.[1]
Link Posted: 9/8/2010 4:14:59 PM EDT
[Last Edit: 9/8/2010 4:16:02 PM EDT by chargerkid5]
Originally Posted By capnrob97:

Originally Posted By Ponyboy:
Originally Posted By California_Kid:
It's interesting that one figure is expressed as mass, and the other as weight. The gravitational pull in Baltimore is higher than it is in Denver, but the difference is negligible.

The change in mass is due to sublimation of part of the mothballs.



Why would the gravitational pull in Baltimore be more than in Denver?


Gravity decreases with altitude.


This and there is a "shorter" column of air pushing down at the higher altitude so air pressure is lower in denver. Same reason its easier to boil water at higher altitude.

Edit: I'm an idiot and need to read the question better.
Link Posted: 9/8/2010 4:15:00 PM EDT
She said that is some sort of trick question, her teacher told her it would be on the classes homework until someone got it right.
Link Posted: 9/8/2010 4:15:13 PM EDT
Correct me if I am wrong but the load is sealed. Meaning even if sublimation happened the gas is still contained inside so that shouldn't cause a loss of mass.
Link Posted: 9/8/2010 4:15:15 PM EDT
Dead moths were dessicated by the time they reached Baltimore.

Plus a small dog was shot at a checkpoint...

Link Posted: 9/8/2010 4:15:35 PM EDT
Sublimation is the answer they are looking for. But, as stated if it is sealed than the mass would be the same. The measured weight would increase at sea level but only a fraction of a gram.
Link Posted: 9/8/2010 4:16:14 PM EDT
Originally Posted By gogoquadzilla:
Originally Posted By GoGop:

Originally Posted By Ponyboy:
The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton?

It was a Dodge; they were afraid to stress the transmission.


Let's assume the teacher wasn't going for the gravity/mass/weight thing, because the question was worded incorrectly as it pertains to that issue.

Sublimation.


But, if you want to get picky, it is not possible for the cargo to lose mass even through sublimation, because it is supposedly a SEALED container.
Link Posted: 9/8/2010 4:18:14 PM EDT
Is that EXACTLY the way the question was worded?
Link Posted: 9/8/2010 4:19:15 PM EDT
[Last Edit: 9/8/2010 4:21:45 PM EDT by Bloencustoms]

Originally Posted By Izzman:
The mothballs turned into a gas and were dispersed, would be my guess.

My take as well.

ETA:

That or possibly the difference in air density due to altitude changes.. The problem is they use both "weight" and "mass" in the problem interchangeably.
Link Posted: 9/8/2010 4:21:08 PM EDT

Originally Posted By dorobuta:
Denver is at 5280 ft MSL, Baltimore is effectively 0 ft MSL



weight is susceptible to gravity.

mass is not.
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