A 2.200-g sample of quinone (C6H4O2) was burned in a bomb calorimeter whose total heat capacity is 7.854 kJ/OC. The temperature of the calorimeter increases from 23.44 OC to 30.57 OC. What is the heat of combustion in kJ per mole quinone?
q = Ccal x dT = 7.854 kJ/oC x 23.44 oC = 184.1 kJ.
That's 184.1 kJ/2.2 g x 108 g/mol = ? kJ/mol
For combustion that usually is shown as a negative value.
Well, if you're looking for the heat of combustion in kJ per mole of quinone, you're probably burning more than just a single clown-sized sample. But I'll try my best to answer your question!
To calculate the heat of combustion, you need to use the formula:
q = C * ΔT
Where q is the heat absorbed, C is the heat capacity of the calorimeter, and ΔT is the change in temperature.
Plugging in the values:
q = 7.854 kJ/°C * (30.57°C - 23.44°C)
Calculating that out gives you:
q ≈ 55.378 kJ
However, this is the heat absorbed by the calorimeter. To calculate the heat of combustion per mole of quinone, we need to convert grams to moles.
First, let's find the molar mass of quinone (C6H4O2):
Molar mass = (6 * Molar mass of carbon) + (4 * Molar mass of hydrogen) + (2 * Molar mass of oxygen)
Molar mass ≈ (6 * 12.01 g/mol) + (4 * 1.008 g/mol) + (2 * 16.00 g/mol)
Molar mass ≈ 108.11 g/mol
Now, let's find the number of moles in 2.200 g of quinone:
Number of moles = Mass / Molar mass
Number of moles ≈ 2.200 g / 108.11 g/mol
Number of moles ≈ 0.02037 mol
To find the heat of combustion per mole of quinone, we divide the heat absorbed by the number of moles:
Heat of combustion per mole ≈ 55.378 kJ / 0.02037 mol
Calculating that out gives you:
Heat of combustion per mole ≈ 2,719.99 kJ/mol
So, approximately your heat of combustion per mole of quinone is 2,719.99 kJ/mol. Hope that puts a smile on your face!
To find the heat of combustion of quinone (C6H4O2) per mole, we need to use the heat capacity of the calorimeter and the temperature change.
Step 1: Calculate the heat absorbed by the calorimeter.
The heat absorbed by the calorimeter can be calculated using the formula:
q = C * ΔT
where q is the heat absorbed, C is the heat capacity of the calorimeter, and ΔT is the change in temperature.
Given:
C (heat capacity) = 7.854 kJ/°C
ΔT (change in temperature) = 30.57°C - 23.44°C = 7.13°C
Plugging the values into the formula:
q = 7.854 kJ/°C * 7.13°C
q = 55.967 kJ
Step 2: Convert the mass of quinone to moles.
We need to convert the mass of quinone to moles using the molecular weight of quinone.
The molecular weight of quinone (C6H4O2) can be calculated as follows:
C (carbon) = 6 * atomic weight of carbon
H (hydrogen) = 4 * atomic weight of hydrogen
O (oxygen) = 2 * atomic weight of oxygen
The atomic weights are:
Atomic weight of carbon = 12.01 g/mol
Atomic weight of hydrogen = 1.01 g/mol
Atomic weight of oxygen = 16.00 g/mol
Calculating the molecular weight:
Molecular weight of quinone (C6H4O2) = (6 * 12.01) + (4 * 1.01) + (2 * 16.00)
Molecular weight of quinone = 126.11 g/mol
Converting the mass of quinone:
mass of quinone = 2.200 g
moles of quinone = mass of quinone / molecular weight of quinone
moles of quinone = 2.200 g / 126.11 g/mol
moles of quinone = 0.01745 mol
Step 3: Calculate the heat of combustion per mole of quinone.
The heat of combustion per mole of quinone can be calculated by dividing the heat absorbed by the moles of quinone.
heat of combustion per mole = q / moles of quinone
heat of combustion per mole = 55.967 kJ / 0.01745 mol
heat of combustion per mole ≈ 3209.83 kJ/mol
Therefore, the heat of combustion per mole of quinone is approximately 3209.83 kJ/mol.
To find the heat of combustion per mole of quinone, we need to calculate the heat transferred to the calorimeter during the combustion process.
The heat transferred to the calorimeter can be calculated using the equation:
q = C * ΔT
Where:
q is the heat transferred to the calorimeter
C is the heat capacity of the calorimeter
ΔT is the change in temperature of the calorimeter
In this case, the heat capacity of the calorimeter (C) is given as 7.854 kJ/°C, and the change in temperature (ΔT) is the difference between the final and initial temperatures of the calorimeter, which is (30.57 - 23.44) °C.
Now, we can substitute these values into the equation to find the heat transferred to the calorimeter:
q = 7.854 kJ/°C * (30.57 - 23.44) °C
q = 7.854 kJ/°C * 7.13 °C
q = 55.888 kJ
So, the heat transferred to the calorimeter during the combustion process is 55.888 kJ.
Next, we need to calculate the number of moles of quinone burned. To do this, we need to use the molar mass of quinone.
The molar mass of quinone (C6H4O2) can be calculated by summing up the atomic masses of carbon (C), hydrogen (H), and oxygen (O):
Molar mass of C = 12.01 g/mol
Molar mass of H = 1.01 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of quinone = (6 * Molar mass of C) + (4 * Molar mass of H) + (2 * Molar mass of O)
Molar mass of quinone = (6 * 12.01) + (4 * 1.01) + (2 * 16.00) g/mol
Now, we can calculate the moles of quinone:
moles of quinone = mass of quinone / molar mass of quinone
moles of quinone = 2.200 g / molar mass of quinone
Finally, we can find the heat of combustion per mole of quinone by dividing the heat transferred to the calorimeter by the number of moles of quinone:
Heat of combustion per mole of quinone = Heat transferred to the calorimeter / moles of quinone
Heat of combustion per mole of quinone = 55.888 kJ / moles of quinone
By plugging in the calculated values, you can find the heat of combustion per mole of quinone.