If the heat of combustion of 1-butanol (C4H9OH) is 2,710 kJ/mol, what mass of oxygen is consumed when enough 1-butanol is burned to yield 26,400 kJ of energy?
I have no clue where to begin I thought to use enthalpy but it didnt work
Isn't it 6 mol of o2
To solve this problem, you need to consider the balanced chemical equation for the combustion of 1-butanol (C4H9OH). The balanced equation is:
C4H9OH + 6O2 → 4CO2 + 5H2O
From the balanced equation, you can see that for every mole of 1-butanol burned, 6 moles of O2 are consumed.
Given that the heat of combustion of 1-butanol is 2,710 kJ/mol, and you want to yield 26,400 kJ of energy, you can set up the following proportion:
(2,710 kJ/mol) / (1 mol) = (26,400 kJ) / (x mol)
Rearranging the equation, you can solve for x:
x = (26,400 kJ) / (2,710 kJ/mol)
Calculating x gives you:
x = 9.73 mol
Therefore, for enough 1-butanol to yield 26,400 kJ of energy, you will need 9.73 moles of 1-butanol.
Since 6 moles of O2 are consumed for every mole of 1-butanol burned, you can calculate the amount of O2 consumed by multiplying the number of moles of 1-butanol by the stoichiometric coefficient of O2:
Amount of O2 consumed = (9.73 mol 1-butanol) * (6 mol O2 / 1 mol 1-butanol)
Calculating this gives you:
Amount of O2 consumed = 58.38 mol
Finally, to find the mass of oxygen consumed, you need to multiply the amount of O2 consumed by its molar mass, which is approximately 32 g/mol:
Mass of O2 consumed = (58.38 mol) * (32 g/mol)
Calculating this gives you:
Mass of O2 consumed = 1868.16 g
Therefore, approximately 1868.16 grams of oxygen would be consumed when enough 1-butanol is burned to yield 26,400 kJ of energy.
To solve this problem, you can use the concept of stoichiometry from chemical reactions. By understanding the balanced equation of the combustion of 1-butanol, you can determine the molar ratio between 1-butanol and oxygen.
The balanced equation for the combustion of 1-butanol (C4H9OH) is:
C4H9OH + O2 -> 4CO2 + 5H2O
From the balanced equation, you can see that for every 1 mole of 1-butanol burned, you need 1 mole of oxygen gas (O2).
Now, let's use a two-step process to calculate the mass of oxygen consumed:
Step 1: Calculate the number of moles of 1-butanol burned:
To find the number of moles of 1-butanol, you can use the formula:
moles = mass / molar mass
The molar mass of 1-butanol (C4H9OH) can be calculated by adding the atomic masses of carbon (C), hydrogen (H), and oxygen (O) in the molecule. Looking up the atomic masses, we find:
C = 12.01 g/mol
H = 1.01 g/mol
O = 16.00 g/mol
So, the molar mass of 1-butanol is:
(4 × C) + (10 × H) + (1 × O) = (4 × 12.01) + (10 × 1.01) + (1 × 16) = 74.12 g/mol
Now, using the given energy of 26,400 kJ and the heat of combustion of 1-butanol (2,710 kJ/mol), we can calculate the number of moles of 1-butanol:
moles of 1-butanol = energy / heat of combustion = 26,400 kJ / 2,710 kJ/mol
Step 2: Calculate the mass of oxygen consumed:
Since the balanced equation indicates a 1:1 molar ratio between 1-butanol and oxygen, the mass of oxygen consumed will be equal to the moles of 1-butanol burned.
mass of oxygen = moles of 1-butanol × molar mass of oxygen
The molar mass of oxygen (O2) is 32 g/mol.
mass of oxygen = moles of 1-butanol × 32 g/mol
Now, you have all the information needed to solve the problem. Simply substitute the values you have obtained into the formula above to calculate the mass of oxygen consumed while burning enough 1-butanol to yield 26,400 kJ of energy.
I hope this explanation helps you understand the process of solving the problem.
C4H10O + 6O2 ==> 4CO2 + 5H2O
Burning 1 mol butanol uses 5 mols O2 (5*32 = 160 grams O2). How many grams O2 will be needed to release 26,400 kJ? That's 160 g O2 x (26,400 kJ/2,710 kJ) = ?