The percent is confusing me, can you please help me set this equation up.
How much heat is liberated when 5.00 kg of coal is burned if the coal is 96.2% carbon by mass and the other materials in the coal do not react?
(delta)H comb of carbon is -394kJ/mol
thank you
If that is all that's confusing you the easiest way to take care of it is that you don't start with 5.00 kg but 5.00 kg x 0.962 = ? kg and I would change that to grams.
mols C = grams/atomic mass C = ?
Then 395 kJ/mol x # mols = ? kJ released. Personally I don't believe in making that a negative sign IF YOU SAY RELEASED since released means it is exothermic. Placing a negative sign means it is saying released released and that doesn't make sense to me.
so would I just do 5.00*.962, then make that into grams, them do 394*C? or where do I find the moles?
I don't think you read my response.
Re-read. mols C = grams/atomic mass C.
Of course! I'd be happy to help you set up the equation.
To solve this problem, we need to use the concept of percent composition and the molar mass of carbon.
First, let's find the mass of carbon present in 5.00 kg of coal. Since the coal is 96.2% carbon by mass, we can calculate it as follows:
Mass of carbon = (96.2/100) * 5.00 kg
Next, we need to convert the mass of carbon to moles. To do this, we need to know the molar mass of carbon. The molar mass of carbon is 12.01 g/mol.
Molar mass of carbon = 12.01 g/mol
To convert the mass of carbon to moles, we can use the equation:
Moles of carbon = Mass of carbon (in grams) / Molar mass of carbon
Now, let's convert the mass of carbon from kilograms to grams:
Mass of carbon (in grams) = Mass of carbon (in kg) * 1000
Once we have the moles of carbon, we can calculate the heat liberated using the equation:
Heat liberated = Moles of carbon * (delta)H comb of carbon
Substituting the values into the equation will give you the answer.