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1. Use given values as stated in questions below. 2. Clearly State Answer 3. (Pl

ID: 795736 • Letter: 1

Question

                    1. Use given values as stated in questions below.                 

                

                    2. Clearly State Answer                 

                

                    3. (Please) LEAVE A COMMENT if you are currently working on the problems.
                

                

                    4. See the following link for the thermo data if needed:                 

                

                    www.mediafire.com/download/t5ja3jz7a3vwb4t/Thermo_Data.docx

5. Points will be awarded if both anwers are correct.
                

                

                    
                

                

                    4. Calculate the mass of methane that must be burned to provide enough heat to convert 330.0 g of water at 37.0

Explanation / Answer


4) Given 330 g of water at 37 C is converted to steam at 124 C


Total Heat required = heat required to convert water at 37 C to 100 C + heat required to convert water at 100 C to steam at 100 C + heat required to convert steam at 100 C to 124 C


total heat required = M Sw dT1 + ML + M Ss dT2

= 330 x 4.18 x (100-37) + 0.33 x 2260 x 103 + 330 x 1.865 x (124-100) )

=330 x 4.18 x 63 + 330 x 2270 + 330 x 2.08 x 24

= 850765.08 J

= 850.765 kJ


So total heat required is 850.765 kJ


The combustion reaction is


CH4 + 202 -----> C02 + 2H20

dH = dHf C02 + 2dHf0(H20) - dHf0 ( CH4)

= -393.5 -2 x 241.8 +74.81

= -802.29 kJ


1 mole of methane gives 802.29 kJ of heat

let y mole of methane give 850.765 kJ of heat


y= 850.765 /802.29

y= 1.00604


so 1.0604 moles of methane is required.


mass of methane = moles x M.W

=1.0604 x 16

= 16.97 g


So mass of methane required is 16.97 grams






17 ) We know that at freezing point


dHo = T dSo

T= dHo/dSo


where T is the freezing point in Kelvin


Given dHo= 0.260 kJ/mol

dSo= 4.851 J /mol K


so T= 0.26 x 1000/ 4.851

T = 53.60 K


Freezing point of fluorine is 53.60 Kelvin