# AS Physics

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17 years ago
#1
omg, im so stuck on writing my as level coursework on the latent heat of vaporisation. I literally dont know where to begin...could any one of u peeps help em out with this one? PLZZZZZ! or guide me to sum sites...already chkecked out coursework.info didnt have it! PLZ PLZ im so stuck
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17 years ago
#2
what's the title?
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17 years ago
#3
the title of the coursework is

investigating the latent heat of vaporisation of water.

Come on ppl help! plz?
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17 years ago
#4
Experiment to measure the Specific Latent Heat of Vaporisationof Water1.Preparation:a) Learn the definition of specific latent heat.b) It is usually found to be easier to measure the quantityof heat given out when steam condenses than tomeasure the quantity of heat needed to vaporise water.(To see that this is true, try to design an experiment inwhich you measure the quantity of heat needed tovaporise 1kg of water.)c) See part 3 below.2. Set up apparatus as shown in the diagram below; it might be convenient touse rubber tubing for the delivery tube. Be careful, it will get HOT !The experiment consists of passing the steam (assumed to be at 100°C)through a known mass of cold water and measuring the temperaturechange produced.Heat the water to boiling point and leave it boiling for a few minutes beforeputting the container of cold water in place.boilingwaterdelivery tubeknown massof cold waterHeat2TP
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Page 2
2Results needed- mass of cold water- initial temperature of cold water- final temperature of cold water- mass of steam which has condensed into the cold water3. a) Why must you wait for a few minutes before putting the container of coldwater in place ? How will you know when the apparatus is ready for use ?b)Derive an equation which will allow you to calculate the specific latentheat of vaporisation of water from your results. Think about the mainsources of error in an experiment like this and how to reduce the effectsof these errors on the precision of the final result.

Specific Latent Heat of Vaporisation of Water
Set up the apparatus as shown in the sketch:

Find the mass of the calorimeter.

Half fill the calorimeter with water. Find the mass again, hence find the mass of the water.

Place the calorimeter in the beaker surrounded by lagging (usually cotton wool).

Note the temperature of the water.

Heat the water in the round bottomed flask and measure the temperature of the steam coming off.

Allow the steam to pass into the calorimeter until the temperature of the water rises by about 15K.

Take the final temperature of the mixture.

Get the mass of the calorimeter + water again, hence find the mass of the added steam.

Calculate the latent heat of vaporisation of water from:

Heat Lost = Heat Gained
Condensing Steam + Boiling Water = Calorimeter + cold water
m L + m c Dq = m c Dq + m c Dq

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17 years ago
#5
Anything else need clearing up?
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17 years ago
#6
Thank you sooooooooooooooooooo much!
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17 years ago
#7
hmm, can anyone help me with the following?

Investigation to measure the Latent heat of Fusion of Ice?!

PLZ IM STUCK!
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17 years ago
#8
It's basically the same, no?
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17 years ago
#9
is it?

but im doing it without cold the use of water, i have to measure the rate at which ice melts at room temp for ten minutes and then how fast it melts with a heater in it. AND I AM S T U C K STUCK!

any help with predictions or nefin would b much appreciated!
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17 years ago
#10
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