Are my answers correct?

C6H14 + 19/2 O2 -> 6 CO2 + 7H2O enthalpy change = -4163 kJ

a) if 0.537 mol of carbon dioxide is produced in the reaction represented by the equation above, how much heat is released by the reaction?

Enthalpy change = 0.537 mol CO2 x -4163kJ/6 mol CO2
=-373 kJ

B) If 25.0 kg of hexane is burned in sufficient oxygen, how much heat will be released?

Enthalpy change = 25000g C6H14 x 1 mol C6H14/86 g x -4163 kJ/1 mol C6H14
= -1.21 x 10^6 kJ

C) what mass of hexane is required to produce 1.0E5 kJ of heat by complete combustion?

1.0E5 kJ = m x 1 mol/86g x 4163/1mol
1.0E kJ = m x -48.45 kJ/g
1.0E kJ/-48.45 kJ/g = m
-2.0E3 g = m
I know this one's wrong since mass can't be negative...

Thanks in advance!

The first two are right.

The last one I would do this way.
4163 kJ/mol x # mols = 1E5 kJ.
Solve for mols. Then g = mols x molar mass.

Sorry, how would you solve for mols? I feel like this should be obvious, but ...

4163 kJmol x #mols = 1E5 kJ.

# mols = 1E5/4163 = ?

Let's go through each of the questions and calculations:

a) To find the amount of heat released by the reaction when 0.537 mol of carbon dioxide is produced, we can use the enthalpy change provided in the equation.

Heat released = 0.537 mol CO2 x (-4163 kJ/6 mol CO2)
= -362.564 kJ

So, the correct answer for part a) is -362.564 kJ.

b) To find the amount of heat released when 25.0 kg of hexane is burned, we need to convert the mass of hexane to moles and use the enthalpy change provided.

First, convert the mass of hexane to grams:
25.0 kg x 1000 g/kg = 25000 g

Next, calculate the number of moles of hexane:
moles of C6H14 = 25000 g / molar mass of C6H14

The molar mass of C6H14 is:
C: 12.01 g/mol * 6 = 72.06 g/mol
H: 1.008 g/mol * 14 = 14.11 g/mol

So, the molar mass of C6H14 is 86.17 g/mol.

moles of C6H14 = 25000 g / 86.17 g/mol

Now, calculate the heat released:
Heat released = moles of C6H14 x (-4163 kJ/mol CO2)
= moles of C6H14 x (-4163 kJ/1 mol C6H14)

Make sure to use the correct mole ratio based on the balanced chemical equation.

The correct answer for part b) will depend on the calculated moles of C6H14 and the equation of the balanced equation.

c) To find the mass of hexane required to produce 1.0E5 kJ of heat, you need to rearrange the equation:

mass = heat released / (enthalpy change per gram)

mass = 1.0E5 kJ / (-48.45 kJ/g)

Make sure to use the correct sign for the enthalpy change, which is negative in this case.

The result you obtained for part c) is incorrect because the mass cannot be negative. Please recheck your calculation.

Remember, it's important to double-check each calculation and pay attention to units to ensure accurate and correct answers.