In a coffee cup calorimeter, 100.0 grams of aluminum chloride is mixed with 100.
ID: 518691 • Letter: I
Question
In a coffee cup calorimeter, 100.0 grams of aluminum chloride is mixed with 100.0 mL of water. The temperature started and 22.5 degree C and ended at 16.9 degree C. Assume the resulting solution has a density of 1.00 g/m L and that the specific heat capacity is 4.184 J/g degree C. Calculate delta H for the reaction in kJ/mol. The specific heat capacity of aluminum is 0.900 J/g degree C. How much energy, in kJ, is needed to raise the temperature of a 6.772 kg block of Al from 22.8 degree C to 65.4 degree C? Consider the combustion of acetylene: 2 C_2H_2 (g) + 5 O_2 (g) rightarrow 4 CO_2 (g) + 2 H_2O (g) delta H degree_rxn = +454 kJ Calculate the heat transferred when 19.88 L of oxygen gas reacts at 38.2 degree C and 2.10 atm.Explanation / Answer
m = 100 g of AlCl3
V = 100 mL = 100 g
Ti = 22.5°C
Tf = 16.9°V
mol = mass/MW = 100/133.34 = 0.74996 mol of AlCl3
Q = m*C(Tf-Ti)
Q = 100*4.184*(16.9-22.5) = -2343.04 J
Hsolution = -Q/n = 2343.04/0.74996 = 3124.21 J/mol = 3.124 kJ/mol