User Panel
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. |
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The mothballs turned into a gas and were dispersed, would be my guess.
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Mothballs evaporate (sublimate?).
1 Kg of mothballs (Naphthalene) changed from a solid to a vapor, decreasing the weight. |
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Difference in air density between Denver and Baltimore? This, I'm geussing. |
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Quoted: The mothballs turned into a gas and were dispersed, would be my guess. |
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A few moths were castrated along the way
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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 |
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I get to ask: Don't moths go after wool and not cotton These are cotton weevils masquerading as moths. |
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The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton?
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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? |
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Quoted: 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. |
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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. |
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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". |
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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 |
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Quoted: Quoted: 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. |
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The correct answer is that the cotton settled, like corn flakes do in the box. Hence, the extra empty space in the box.
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Quoted: Fair enough.Quoted: I get to ask: Don't moths go after wool and not cotton These are cotton weevils masquerading as moths. |
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Quoted: The real question is, who the fuck builds a truck so small that it can only hold 100kg of cotton? Union Labor. |
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Think it would be more of the cotton drying out than the naptholene evaporating.
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Scales are not calibrated to 100% of each other.
I have no idea. |
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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. |
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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. |
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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. |
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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. |
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Quoted: Right. But the problem used the term "mass" as the thing that decreased.Quoted: Quoted: Quoted: 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. Another likely possibility is a confused teacher.
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depending on what "sealed container" means, the pressure inside would still be the same as it was in Denver (ie less than air pressure)
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Quoted: 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. |
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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? |
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Quoted: Quoted: 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. |
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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.
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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. |
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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. |
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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. |
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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]
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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. |
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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.
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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.
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Dead moths were dessicated by the time they reached Baltimore.
Plus a small dog was shot at a checkpoint... |
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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.
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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. |
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Quoted: 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. |
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Quoted: Denver is at 5280 ft MSL, Baltimore is effectively 0 ft MSL weight is susceptible to gravity. mass is not. |
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