When 0.558g of biphenyl (C_12H_10) undergoes combustion in a bomb calorimeter, the temperature rises from 25.7^\circ C to 30.1^\circ C. Find DeltaE_rxn for the combustion of biphenyl in kJ/mol biphenyl. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.86 kJ/{^\circ C}.
q = Ccal x delta T
dE/g biphenyl = q/0.5585 in kJ/g.
dE in kJ/mol = kJ/g x molar mass biphenyl.
Then c
what is Ccal?
calorimeter constant.
Show your work if you have trouble.
To find ΔE_rxn for the combustion of biphenyl in kJ/mol biphenyl, you can use the equation:
ΔE_rxn = q / n
where:
ΔE_rxn is the change in internal energy of the reaction (in kJ/mol),
q is the heat absorbed by the reaction (in kJ), and
n is the number of moles of biphenyl.
First, we need to calculate the heat absorbed by the reaction (q). We can do this using the equation:
q = msΔT
where:
m is the mass of biphenyl (in g),
s is the specific heat capacity of the bomb calorimeter (in kJ/g°C),
ΔT is the change in temperature (in °C).
Given that the mass of biphenyl is 0.558 g, the specific heat capacity of the bomb calorimeter is 5.86 kJ/°C, and the change in temperature is (30.1°C - 25.7°C) = 4.4°C, we can calculate q as follows:
q = (0.558 g) x (5.86 kJ/g°C) x (4.4°C)
q = 14.736 kJ
Next, we need to find the number of moles of biphenyl (n). To do this, we can use the molar mass of biphenyl.
The molar mass of biphenyl (C12H10) is:
12(12.01 g/mol) + 10(1.008 g/mol) = 154.175 g/mol
Now we can calculate the number of moles (n) using the mass and molar mass:
n = (0.558 g) / (154.175 g/mol)
n = 0.00361 mol
Finally, we can substitute the calculated values of q and n into the equation for ΔE_rxn:
ΔE_rxn = q / n
ΔE_rxn = 14.736 kJ / 0.00361 mol
ΔE_rxn = 4074.515 kJ/mol biphenyl
Therefore, the ΔE_rxn for the combustion of biphenyl is 4074.515 kJ/mol biphenyl.