Question

The combustion of coal with oxygen forms and releases of energy.

How much energy is released when of reacts? Be sure your answer has the correct number of significant figures. How many Kcal of energy releases?

Answer 1

The balanced chemical equation for the combustion of coal with oxygen is:

C + O2 -> CO2

From the equation, we can see that when 1 mole of carbon reacts with oxygen, it produces 1 mole of carbon dioxide.

The standard enthalpy change for the combustion of carbon to form carbon dioxide is -394 kJ/mol.

Therefore, when 1 mole of carbon reacts, 394 kJ of energy is released.

To find out how much energy is released when a specific amount of carbon reacts, we need to first determine the number of moles present.

Let's assume we have 100 grams of carbon.

The molar mass of carbon is approximately 12 g/mol.

Therefore, 100 g of carbon is equal to 100/12 = 8.33 moles of carbon.

Since 1 mole of carbon releases 394 kJ of energy, 8.33 moles of carbon would release:

8.33 moles x 394 kJ/mole = 3283.02 kJ

To convert this to kcal, we need to divide by 4.184 (1 kJ = 4.184 kcal):

3283.02 kJ / 4.184 = 785.2 kcal

Therefore, 100 grams of carbon would release approximately 785.2 kcal of energy when it reacts with oxygen to form carbon dioxide.