Calculating Latent Heat of Water Vaporization

AI Thread Summary
The discussion focuses on calculating the specific latent heat of vaporization of water using experimental data. Key observations include an initial water mass of 400g, a final mass of 450g after condensation, and temperature changes from 16°C to 70°C for both water and calorimeter. The heat lost by the steam is set equal to the heat gained by the water and calorimeter, leading to a complex equation that the poster struggles to solve correctly. The tutor indicates that the formula used is incomplete, prompting the request for assistance in identifying the error. Clarifying the equations and ensuring all variables are correctly accounted for is essential for resolving the calculation.
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Homework Statement



from the following observations made during an experiment, determine the specific latent heat of vaporisation of water.

initial mass of water 400g, final mass of water 450g (the extra is condensed steam)

mass of calorimeter 200g, initial temp of water & calorimeter 16 C

final temp of water & calorimeter 70 C , specific heat capacity of water 4200j/kg C

specific heat capacity of calorimeter 420 j/kg C

HINT heat lost by steam= heat gained by water + heat gained by calorimeter


Homework Equations



quantity of heat = mass x specific heat capacity x temperature change

The Attempt at a Solution



let suffix c = calorimeter
w = water

mc cc tc = mw cw tw + fmw cw t

-200 x 420 ( 70 tc) = 400 x 4200 ( 16 t) + 450 x 420 ( 16 t)

- 84000 ( 70 tc) = 168,0000 ( 16 t) + 189,000 (16 t)

-84000 ( 70 tc) = 1869000 ( 16 t)

- 84000 c + 5.88 x 10 6 = 1869000 c 29.904 x 10 6

5.88 x 10 6 +29.904 x 10 6 = 1869000 c 84000 c


35.784 x 10 6 = c (1869000 + 84000 ) = 1953000 c


c = 35.784 x 10 6 / 1953000 = 18.322 C


MY TUTOR HAS SAID MY FORMULA IS INCOMPLETE BUT I DONT NO WHERE I HAVE GONE WRONG PLEASE HELP MARK.
 
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