posted by kayla on .
In the following experiment, a coffee-cup calorimeter containing 100ml of H2O is used. The initial temperature of the calorimeter is 23 degrees celcius. If 7.20g of CaCl2 is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of solution of CaCl2 is -82.8kj/mol .
Please note the correct spelling of Celsius.
How much heat does the CaCl2 add to the water? That is 7.2 g (1 mol/molar mass CaCl2) x (82,800 Joules/mol).
Then q = mass water x specific heat water x (Tf-Ti) where Tf is the final T and Ti is the initial T. Most dilute solutions will have a density for the solution of 1.0 g/mL; therefore, 100 mL has a mass of 100 grams. The specific heat of water is 4.184 J/g*C. Post your work if you get stuck.
Johns answer is incorrect. who can answer this correctly?
34.9 degrees Celsius.
1) convert CaCl2 to moles then multiply it by 82.8kj/mol to find the heat of CaCl2.
2) Use the q=mct equation. Make sure the mass is the TOTAL MASS (of water + CaCl2)
hope this helps! :)