# Calculate Heat of Combustion of Graphite

• Hamal_Arietis
In summary: Yes, and ...And 1 mol of C is burned and 1 mol of CO is generated, but only 0.5 mol of CO was formed from the incomplete combustion. So the heat released is actually half of what you calculated, which is 253 kJ/mol.
Hamal_Arietis

## Homework Statement

The heat of combustion of graphite and that of CO is 394kJ/mol and 283 kJ/mol, respectively. When 12g of graphite is combusted incompletely, the same volume of CO and CO2 are generated. Calculate the heat of generated by this combustion. Choose the closet value.(kJ)
A.197 B.253 C.308 D.339 E.505 F.677

## The Attempt at a Solution

My idea is:
##C+O2→CO\\
##CO+O2→CO2\\
So ##ΔH=ΔH_1+ΔH_2=-535,5kJ/mol##
Where is my wrong?
Thanks for helping

Hamal_Arietis said:
Where are my wrong?
Hamal_Arietis said:
Wrong.
Ask yourself, "How many moles of carbon have been burned? How many moles of gaseous products have been formed? What is the minimum heat?"

Bystander said:
How many moles of gaseous products have been formed?
I think 0,5 mol CO and 0,5 mol CO2 are generated and 1 mol C is combusted

Hamal_Arietis said:
I think 0,5 mol CO and 0,5 mol CO2 are generated and 1 mol C is combusted
Correct. And the minimum heat released is what?

Bystander said:
Correct. And the minimum heat released is what?
I don't know.
##C+O2→CO\\
##CO+O2→CO2\\
So ##ΔH=ΔH_1+ΔH_2=-535,5kJ/mol##
1 mol of C is combusted and 0,5 mol of CO and CO2 are generated . So the heat is -535,5kJ/mol?

What's half a mol x 394 kJ/mol?

Bystander said:
What's half a mol x 394 kJ/mol?
197kJ/mol
but 1 mol C is burned, not 0,5 mol. And 1mol CO is generated but 0,5 mol CO is burned and 0,5 mol CO2 is generated.

Yes, and ...

## 1. What is the definition of heat of combustion?

The heat of combustion is the amount of energy released when a substance is completely burned in the presence of oxygen, producing heat and light as byproducts.

## 2. How do you calculate the heat of combustion of graphite?

The heat of combustion of graphite can be calculated by measuring the amount of heat produced when a known mass of graphite is burned completely in a controlled environment, and then using the formula Q = m*c*ΔT, where Q is the heat energy, m is the mass of the graphite, c is the specific heat capacity of graphite, and ΔT is the change in temperature. This will give the heat of combustion in joules.

## 3. What is the specific heat capacity of graphite?

The specific heat capacity of graphite is approximately 0.71 J/g°C.

## 4. How does the heat of combustion of graphite compare to other substances?

The heat of combustion of graphite is relatively low compared to other substances such as hydrocarbons, which can have heat of combustion values of thousands of joules per gram. This is because graphite is a relatively stable and unreactive substance.

## 5. Why is it important to calculate the heat of combustion of graphite?

Calculating the heat of combustion of graphite is important for understanding its energy potential and its role in various combustion processes. It can also be used in the design and optimization of industrial processes that involve the burning of graphite, such as in power generation or fuel production.

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