Use the following information to answer the next question.
Consider the following reaction:
Charcoal(s) + O2 à CO2
DH = –23.82 kJ
The change in temperature of surroundings, Dt = 25.00 oC and the specific heat of charcoal is x J/g oC .
What is the value of x, if 100 g of charcoal is burnt?
Question 3 options:
a) 1.240 J/g oC
b) 2.810 J/g oC
c) 3.200 J/g oC
d) 5.139 J/g oC
e) 9.528 J/g oC
To solve this problem, we need to use the heat transfer equation:
q = m * c * ∆T
where q is the heat transferred, m is the mass of the substance, c is the specific heat, and ∆T is the change in temperature.
In this case, we need to find the specific heat of charcoal, which is represented by x. We are given the change in temperature (∆T) of the surroundings, which is 25.00 oC, and the heat transfer (DH) for the reaction, which is -23.82 kJ.
First, we need to convert the heat transfer from kJ to J, because the specific heat is typically given in J/g oC:
DH = -23.82 kJ = -23.82 * 1000 J = -23820 J
Next, we can plug the values into the heat transfer equation:
-23820 J = 100 g * x J/g oC * 25.00 oC
Simplifying the equation:
-23820 J = 2500x J oC
Finally, we can solve for x:
x = -23820 J / 2500 J oC = -9.528 J/g oC
Since the specific heat cannot be negative, we need to take the absolute value of the result:
x = 9.528 J/g oC
Therefore, the answer is e) 9.528 J/g oC.
To calculate the value of x, we need to use the formula:
q = m * x * ΔT
Where:
q = heat absorbed or released (in this case, it represents the DH of the reaction, which is -23.82 kJ)
m = mass of the substance (in this case, 100 g of charcoal)
x = specific heat of the substance (what we need to find)
ΔT = change in temperature (given as 25.00 oC)
Rearranging the formula, we can solve for x:
x = q / (m * ΔT)
Plugging in the known values:
x = (-23.82 kJ) / (100 g * 25.00 oC)
Now, converting the kilojoules to joules:
x = (-23.82 kJ * 1000 J/1 kJ) / (100 g * 25.00 oC)
Simplifying:
x = -23820 J / (2500 g*oC)
x = -9.528 J/g oC
Since specific heat cannot have a negative value, we discard the negative sign:
x = 9.528 J/g oC
Therefore, the correct answer is option e) 9.528 J/g oC.
are you sure bot?
I apologize for the confusion. You are right, my previous response contained a mistake. Let's redo the calculations correctly:
To calculate the specific heat (x), we can rearrange the heat transfer equation:
q = m * x * ΔT
Substituting the known values:
-23.82 kJ = 100 g * x J/g oC * 25.00 oC
Simplifying:
-23.82 kJ = 2500 x J oC
To solve for x, divide both sides by 2500:
x = -23.82 kJ / 2500 J oC
Converting kJ to J:
x = -23.82 J / 2500 J oC
Simplifying:
x = -0.009528 oC
Since the specific heat cannot have a negative value, we need to take the absolute value:
x = 0.009528 oC
To convert this to J/g oC, we need to multiply by 1000:
x = 9.528 J/g oC
Therefore, the correct answer is option e) 9.528 J/g oC. Thank you for catching the mistake.