I believe in most countries you can do homeschooling but you still need to do some preliminary tests to show u actualy mastered everything you were supposed too. I am pretty sure that if Khan Academy actualy made a real program it would knock most college's off their ground. Khan Acadamy FTW!
@khanacademy can you please upload more videos on thermochemistry. it would help me out a lot if you did, and also how to incorporate the equations there are in thermochemistry.
When doing the conversion from Celsius to kelvin, don't you have to convert your units in order to cancel out the specific heat in kelvin with the heat change in celsius from solid to liquid ice?
He explained it in previous videos. Basically not really because the degree increments are the same for both scales. Only Kelvin 0 (start) is at -273 Celsius. So 0C is actually 273K. Going from -10C to 0C is the same as going from 263 to 273. Still 10 degrees on both scales.
Celsius and Kelvin have different starting point, one at 0 degree C and one at 273 K, but the degree increments are the same for both scales. If you increase the temperature by 1 degree Celsius, it's the same as you increase the temperature by 1 Kelvin, not 273 Kelvin.
lmao I had the hardest time with this stuff back at school...then again they never explained but just numbers in your face really fast without explaining the bonds and all the other real interesting stuff. Amazing....Khan academy should replace every chemistry and physics class :P
If you are not trying to chill the water to 0 C and were trying to chill the water to 5 C would you use the amount of energy that 0 C water has to also help bring the water down to 5 C?
In this problem the formula q = m*c*ΔT assumes you are dealing with an isolated "system" or region of the universe separated from it's surroundings by a "boundary" that limits a reasonable amount of energy transfer. Although it is really impossible to completely isolate a system from its surroundings, generally the heat exchanged across the boundary is so minuscule that for these macroscopic type of word problems it can be ignored so you can focus on the relationships between mass and energy.
@MsChaChingChaChing You are referring to Kinetics, which refers to the RATE at which a particular transformation or reaction occurs. All questions related to thermochemistry, like the one addressed in the video, deal with thermodynamics. Thermodynamics only concerns the initial and final (equilibrium) states and does not concern the rate at which a particular transformation or reaction occurs.
am i right in assuming that as there is no temperature change in the phases of the water molecules that a pressure/volume change takes place(?) and also i see the paradox of ice expanding when cooled or is this a drastic change in its pressure?
+BAdBrAd yes delta T can be written as negative. and no mass doesn't have to be negative. Heat added to ice + Heat added to water = 0 Heat added to ice = -(Heat added to water) -(-60) = 60
After working a 1.0 kg iron horseshoe with a temperature of 500 °C on an anvil, a blacksmith drops it into a bucket that contains 10 kg of water with an initial temperature of 20 °C. Assuming no heat is transferred to the environment, determine the final temperature of the horseshoe in the bucket of water when thermal equilibrium is achieved. The specific heat capacity of iron is 450 J/kg•C°.
Why can't the ice absorb more energy as it melts to water to gain more tempreature (above 0 degress celsius) by gaining the energy "released" by the liquid water at 60 degress celsius?
wait but shouldn't time play a factor? the problem never states how fast you want the water to go down to 0degrees C. you only say it needs to cool down. cna't i just place a big chunk of ice, so that it goes down to 0 degrees C but maybe even go past it? the problem never specified it had to stay at 0degrees C, so i can cool it down past 0 degrees C.
6. How much ice would be needed to cool the original drawing room in Hatchlands (estimated to be 3 m x 6 m x 9 m) from 28 oC to 23 oC? Assume the walls of the room have negligible heat capacity and act as a perfect insulator and the final temperature of the water is 20 oC. Can anyone do this? I am so lost
Prabhanshu Katiyar because the amount of moles a calculator contains is equivalent to the specific heat in grams of the ice minus the water. that's why he pronounces it as calcualatuor
i love the way this guy explains things. he has the ability to make people understand, at least for me he really does.thanks khan
I have a quiz on this stuff tomorrow and I have been completely lost the whole week. I watched this and pretty much instantly understood.
Great video!
I believe in most countries you can do homeschooling but you still need to do some preliminary tests to show u actualy mastered everything you were supposed too. I am pretty sure that if Khan Academy actualy made a real program it would knock most college's off their ground. Khan Acadamy FTW!
Great stuff! 😊
@khanacademy can you please upload more videos on thermochemistry. it would help me out a lot if you did, and also how to incorporate the equations there are in thermochemistry.
Shit.. Im just learning this. I've never stretched these nurons before.
Ima pull somthing for sure
When doing the conversion from Celsius to kelvin, don't you have to convert your units in order to cancel out the specific heat in kelvin with the heat change in celsius from solid to liquid ice?
that's exactly what I wanted to say
He explained it in previous videos. Basically not really because the degree increments are the same for both scales. Only Kelvin 0 (start) is at -273 Celsius.
So 0C is actually 273K. Going from -10C to 0C is the same as going from 263 to 273. Still 10 degrees on both scales.
A change in celcius is the same as a change in kelvin
Celsius and Kelvin have different starting point, one at 0 degree C and one at 273 K, but the degree increments are the same for both scales.
If you increase the temperature by 1 degree Celsius, it's the same as you increase the temperature by 1 Kelvin, not 273 Kelvin.
lmao I had the hardest time with this stuff back at school...then again they never explained but just numbers in your face really fast without explaining the bonds and all the other real interesting stuff. Amazing....Khan academy should replace every chemistry and physics class :P
If you are not trying to chill the water to 0 C and were trying to chill the water to 5 C would you use the amount of energy that 0 C water has to also help bring the water down to 5 C?
man!!!!!!.u r great.u r really great.
Wouldn't the change in temperature be a negative value?
(Temp final- temp initial ) = change in temp
In this problem the formula q = m*c*ΔT assumes you are dealing with an isolated "system" or region of the universe separated from it's surroundings by a "boundary" that limits a reasonable amount of energy transfer. Although it is really impossible to completely isolate a system from its surroundings, generally the heat exchanged across the boundary is so minuscule that for these macroscopic type of word problems it can be ignored so you can focus on the relationships between mass and energy.
How do you convert 60C water volume to mass 😁. I'd love to know. Is there a correction factor due to density?
@MsChaChingChaChing You are referring to Kinetics, which refers to the RATE at which a particular transformation or reaction occurs. All questions related to thermochemistry, like the one addressed in the video, deal with thermodynamics. Thermodynamics only concerns the initial and final (equilibrium) states and does not concern the rate at which a particular transformation or reaction occurs.
am i right in assuming that as there is no temperature change in the phases of the water molecules that a pressure/volume change takes place(?) and also i see the paradox of ice expanding when cooled or is this a drastic change in its pressure?
Is Temperature an absolute value in this case or something? Cause if you are decreasing temperature deltaT should have a negative value. Thanks
theres no such thing as negative MASS. that is why .
+Noel Atilano Thank you
+BAdBrAd yes delta T can be written as negative. and no mass doesn't have to be negative.
Heat added to ice + Heat added to water = 0
Heat added to ice = -(Heat added to water)
-(-60) = 60
+JZoidberg Thanks
I LOVE THIS !!!!!!!!!!!!!!!!!!!!!!!!!
After working a 1.0 kg iron horseshoe with a temperature of 500 °C on an anvil, a blacksmith drops it into a bucket that contains 10 kg of water with an initial temperature of 20 °C. Assuming no heat is transferred to the environment, determine the final temperature of the horseshoe in the bucket of water when thermal equilibrium is achieved. The specific heat capacity of iron is 450 J/kg•C°.
thank you
Calculatooouuuurrrrr :D
How do you solve to find the final temperature of system if you don't know the final temp?
You saved my life
i dont get why u keep this C instead of switching it to K
can anyone explain?
My students used to compete to be the first one to get ice for the class. That meant they got to leave lab in the middle of class.
@imasexyborat Im doing Both Chem and Phys. Which module of Physics was it?
Why can't the ice absorb more energy as it melts to water to gain more tempreature (above 0 degress celsius) by gaining the energy "released" by the liquid water at 60 degress celsius?
The fact that i gotta do all that for *ONE* problem tells me school aint for me
could you make a properties of water video
8:37
Cracks me up XD
H=cp×m×T is an equation you should memorize.
I didn't put delta before H or T so it's in absolute units. Don't take away my points!
ty
How can you do the calculation without knowing what the letters/symbols means and their units?
It’s after 13 years that i’m telling you that a change in celcius is the same as a change in kelvin
Thanks now I can finally complete my homework.
@@Nashy119 lmao
But the question I have is, how long in terms of seconds it takes to cool the water by just one degree Celsius?
A big chonco-ice xD aw I love sal lmao
wait but shouldn't time play a factor? the problem never states how fast you want the water to go down to 0degrees C. you only say it needs to cool down. cna't i just place a big chunk of ice, so that it goes down to 0 degrees C but maybe even go past it? the problem never specified it had to stay at 0degrees C, so i can cool it down past 0 degrees C.
wouldn't it be in milliliters if it's water?
Why is 125,340/354,05 equal to 345,02. That doesn't seem right ?
he didn't have to justify that technical clinch ju know
its a closed system.
OMG! i UNDERSTAND! 0.0
#26
Don't units cancel in end? How is Sal's answer end in grams?
Now looking back, I think it's because it's x grams of ice we are looking for. Thx😀
no dislikes
that was a year ago thing have changed
HAHA hoo
doesn't 20.5X + 333.55X = 354.05 x 2X witch is 708.1X?
so X = 125,340/708.1? (177.01g)
6. How much ice would be needed to cool the original drawing room in Hatchlands (estimated to be 3 m x 6 m x 9 m) from 28 oC to 23 oC? Assume the walls of the room have negligible heat capacity and act as a perfect insulator and the final temperature of the water is 20 oC. Can anyone do this? I am so lost
why does he say calculator as calculataur
he was just joking
Prabhanshu Katiyar because the amount of moles a calculator contains is equivalent to the specific heat in grams of the ice minus the water. that's why he pronounces it as calcualatuor
what????!!!