#8 please and show work. thank you. Changes of Phase Problems: For each of the l

Question

#8 please and show work. thank you.

Changes of Phase Problems: For each of the lowowing drew a sketch and problem. (Report your answer in ks for 13 use calories o 5. Determine the amount of heat needed to the ature of 200 goms to water at 80.0°C 6. Find the heat lost by 20.0 grams of water at 40 oec to form ce at 20e 7. How much heat energy is needed raise the temperature ol 500 gorrs dice of to 10.0oC form steam 120.0 8. Calculate the amount of heat lost by v200 grams of steam at 1500cto oumice at 15.0oC. removed from 2000 gams veom 9. Determine the amount of heat that must be water at 20.0oC. 10. How much heat is required to raise the temperature of 300 got Ho at 150oC (Don't forget the phase changes). 11. Xylene has the following constants: M.P. c.BP. 80oc.Ht grams ecific Heat soid cal/goc, given off when 400 (mych heat is

Explanation / Answer

The amount of heat lost ,

Q = heat change for conversion of vapour at 150 oC to vapour at 100 oC + heat change for conversion of steam at 100 oC to water at 100 oC + heat change for conversion of water at 100oC to water at 0 oC + heat change for conversion of water at 0oC to ice at 0oC + heat change for conversion of ice at 0 oC to ice at -15 oC

Amount of heat released , Q = mcdt + mL + mc'dt + mL' + mc"dt"

                                              = m(cdt + L + c'dt' + L' + c"dt" )

Where

m = mass of steam = 120.0 g

c = Specific heat of steam = 2.1 J/g degree C

c' = Specific heat of water = 4.186 J/g degree C

c" = Specific heat of ice= 2.09 J/g degree C

L = Heat of Vaporization of water = 2260 J/g

L'= Heat of fusion of ice = 334.9 J/g

dt = 150-100 = 50oC

dt' = 100 -0 =100 oC

dt'' = 0-(-15) = 15 oC

Plug the values we get Q = m(cdt + L + c'dt '+ L' + c"dt" )

= 378.0x103 J

= 378.0 kJ

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