Calorimetry: Calculate Specific Heat, Atomic Weight, Heat of Solution & Reaction

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SUMMARY

This discussion focuses on the calculations involved in calorimetry, specifically determining the specific heat of a metal, atomic weight using Dulong and Petit’s rule, heat of solution, and heat of reaction. The participants provide specific mass and temperature data for various experiments involving metals and salts, with calculations based on the principles of thermodynamics. Key calculations include the specific heat of the metal at 0.264 J/g°C, the heat of solution at -75.180 kJ/mol, and the need for clarity on limiting reagents in reaction calculations.

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  • Understanding of calorimetry principles
  • Familiarity with specific heat calculations
  • Knowledge of Dulong and Petit’s rule for atomic weight
  • Basic thermodynamic equations for heat of reaction
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  • Learn how to calculate specific heat using calorimetry
  • Study Dulong and Petit’s rule for determining atomic weights
  • Research methods for calculating heat of solution
  • Explore limiting reagent concepts in chemical reactions
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purpletouch
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to the admin. pls. don't delete this i figure it be easier to understand this if it's set up this way because its a prelab.thanks

I. 89.7716 g of metal were heated to 99.8 °C and poured into a calorimeter containing 46.20 g of water at 28.45 °C.
After stirring, the temperature of the water rose rapidly to 36.25 °C before slowly starting to fall.
Calculate:
a) The Specific Heat of the metal _____________
b) The Atomic Weight _____________
Calculated using the rule of Dulong and Petit

II. To a calorimeter containing 48.80 g of water at 28.85 °C, 7.0545 g of a salt was added with stirring. As the salt dissolved, the temperature rapidly changed to 31.45 °C before slowly returning to room temperature.
Calculate:
c) The Heat of Solution ______________

Given that the Heat of Formation of the solid salt is... -180.59 Kj/mol
and the Molecular Mass of the solid salt is... 143.69 g/mol
Calculate:
d) The Heat of Formation of the Solution ______________ Kj/mol

III. Given the reaction... AAA + BBB ---> CCC
You add to a calorimeter 8.0 mL of 5.65 M AAA, 5.0 mL of water, and 12.0 mL of 5.51 M BBB. All of the above solutions were initially at 29.10 °C. After mixing, the temperature changed to 30.60 °C.
Assume the density of all solutions is 1.000 g/mL and all solutions have the same specific heat as pure water.
Calculate:
e) The Heat of Reaction in Kj/mol ______________

i don't know how to get B D and E

for A i got .264
for B i divided .264 from 6 but the answer is wrong. i tried it with 6.2 but it I'm still not getting the right answer
C=-75.180
D. i really don't have a clue
E. I'm given this formula but I'm stuck on limiting reagant
(Volume in mL)(Molarity) = millimoles
VolumeHCl + VolumeNaOH+ Volumewater = Volumeliquids
Temperaturefinal-Temperatureinitial = Temp. Changeliquids
(Massliquids)(-Temp. Changeliquids)(4.18 j/gºC) = Energy Change
Energy Change/[(1000 j/Kj)(Moles of Limiting Reagent)] = DH Reaction

thanks!
 
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purpletouch said:
for A i got .264


Can you show how you got that? And please include units. I think you did a unit conversion incorrectly, but without seeing your work and what units you mean to use, there is no way to tell.
 

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