Question 16
8 Points
Silver is known to be an excellent conductor of heat and electricity. if 8.20 kJ of energy are provided, calculate the energy required (Joules - just put in the number, 4 sig figs) to heat 14.25 g of silver from 25.00 °C to its melting point BLANK-1, the energy required (kJ - just put in the number, 4 sig figs) to melt the silver BLANK-2, and determine whether the silver will reach the boiling point. (yes/no) BLANK-3. What will the final temperature of the silver be (oC - just put in the number, 4 sig figs) BLANK-4? (Do not include commas in your answers, give all numeric answers to 4 significant figures, do not use scientific notation)
{heat capacity of solid silver = 24.80 J K-1 mol-1, heat capacity of liquid silver 33.40 J K-1 mol-1, heat capacity of gaseous silver 21.10 J K-1 mol-1, ΔHfus (Ag) = 11.97 kJ/mol, ΔHvap (Ag) = 250.6 kJ/mol, m.p. Ag = 962.0° C, b.p. Ag = 2212° C }
1b)
Part 1
Calculation for heat required to increase the temperature of silver from 250 to its melting point (9620)
heat capacity of Silver = 24.80 J K-1 mol-1
moles of Silver = ( mass / molar mass) = ( 14.25/107.8) = 0.132
H1 = moles of silver heat capacity of solid silver temperature change
= 0.132 24.80 ( 962 - 25)
= 3067 J
= 3.067 KJ
answer of Blank 1 = 3.067 KJ
Part 2
Calculation for heat required to melt silver
H2 = moles of Silver Enthalpy of fusion of Silver
= 0.132 (mol) 11.97 (KJ/mol)
= 1.580 KJ
Answer of BLANK 2 is 1.580 KJ
Part 3
Total heat remains = 8.20 KJ - ( H1 +H2) = 8.25 - (3.067 + 1.580) = 3.602 KJ
now heat required to reach boiling point of liquid silver
H3 = moles of silver heat capacity of liquid silver temperature change
= 0.132 33.40 ( 2212 - 962)
= 5511 J
= 5.511 KJ
As heat required to raise the temperature to boiling point is less than heat remain after melting of silver , so it will not reach boiling point.
Therefore answer of BLANK 3 is NO.
part 4
Heat = moles of silver heat capacity of liquid silver temperature change
or .3.602 1000 (J ) = 0.132 33.40 ( Tf - 962)
or 3602 = 4.4088 ( Tf - 962)
or, ( Tf - 962) = 817
or, Tf = 1779 0c
Hence final temperature is 1779 0c.
answer of BLANK 4 is 1779 0C.
Question 16 8 Points Silver is known to be an excellent conductor of heat and electricity....
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