Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Lodve on August 23, 2010, 03:53:40 PM
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A rock is placed on a balance and its mass is determined as 12.1 g. When the rock is then placd in a graduated culynder that originally contains 11.3 mL og water, the new volum is roughly 17 mL. How should the density of the rock be reported?
This task doesn't seem hard at all for those who have had chemistry, but I don't know why I can't solve it. I'm relatively new here, so don't get irritated if I post easily tasks. I've never had chemistry before, so it's kinda new for me :P
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What is definition of density?
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mass divided to volum?
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Good. Can you calculate mass and volume from a given data?
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Ahhh, you just divide 12.1g to 17mL which will give 0.711g/ml?
You know, I don't have the answer to this question :P
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Ahhh, you just divide 12.1g to 17mL which will give 0.711g/ml?
No you forgot to account for the volume of the water.
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How am i going to do that?
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Final volume is initial plus volume of the solid.
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Well according to Archimedes' principle, "Any object, wholly or partially immersed in a fluid, buoyed up by a force equal to the weight of the fluid displaced by the object," which means in simple words, the volume of displaced fluid is equal to the volume of the sunken object.
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A rock is placed on a balance and its mass is determined as 12.1 g. When the rock is then placd in a graduated culynder that originally contains 11.3 mL og water, the new volum is roughlyhermes (http://www.eluxurys-store.com/hermes.html) 17 mL. How should the density of the rock be reported?
This task doesn't seem hard at all for those who have had chemistry, but I don't know why I can't solve it. I'm relatively new here, so don't get irritated if I post easily tasks. I've never had chemistry before, so it's kinda new for me Tongue
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A rock is placed on a balance and its mass is determined as 12.1 g. When the rock is then placd in a graduated culynder that originally contains 11.3 mL og water, the new volum is roughly 17 mL. How should the density of the rock be reported?
This task doesn't seem hard at all for those who have had chemistry, but I don't know why I can't solve it. I'm relatively new here, so don't get irritated if I post easily tasks. I've never had chemistry before, so it's kinda new for me :P
Sorry Lodve but this isn't chemistry at all. It's mostly Mathemetics with a tiny bit of physics.
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17-11.3=5.7 ml
1 ml = 1cm³
12.1g/5.7cm³ = 2.12g/cm³
Correct me if i'm wrong
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I think I just divide 12.1g to 17mL since the volume is increasing after the stone is placed on the graduated cylinder. I don't think this task wasn't meant to be that hard :P
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This way you are ignoring fact that you started with 11.3 mL of water.
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I think I just divide 12.1g to 17mL since the volume is increasing after the stone is placed on the graduated cylinder. I don't think this task wasn't meant to be that hard :P
The task isn't that hard if you have a brain. How many times do you need to be told this is wrong and that you need to take into account the volume of water before you actual listen?
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An object placed in water will displace a volume of water equal to the volume of the object.
This is correct:
17-11.3=5.7 ml
1 ml = 1cm³
12.1g/5.7cm³ = 2.12g/cm³
The way you want to do it would give you a rock with a density lower than water. I don't see many floating rocks!
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12.1g/5.7cm³ = 2.12g/cm³
12.1g/5.7cm³ = 2.12g/cm³
What it is with you people, is it so hard to read forum rules (http://www.chemicalforums.com/index.php?topic=33740.0)? We don't give exact answers.
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12.1g/5.7cm³ = 2.12g/cm³
12.1g/5.7cm³ = 2.12g/cm³
What it is with you people, is it so hard to read forum rules (http://www.chemicalforums.com/index.php?topic=33740.0)? We don't give exact answers.
Probably down to frustration BoreK; the OP seems to have a rock like density and is incapable of recognizng help when given. Even spoon feeding the correct answer once didn't seem to take.
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I just copied an already posted answer.
My point was the poster should have logically figured out his density answer was incorrect.
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Also, not to be technical about rules, but I do not believe the answer is exact. I believe the significant digits in the answer I posted are incorrect.
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the OP seems to have a rock like density
;D
d=m/v
mass-you have
volume- of the rock, which is equal to that of the water displaced.