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
I worked this problem for you about 4 or 5 yours ago. Here is a link.
https://www.jiskha.com/display.cgi?id=1512514097
LOL. HOURS ago.
To solve this problem, we can use the balanced chemical equation for the combustion of 1-butanol:
C4H9OH + 6O2 -> 4CO2 + 5H2O
From the equation, we can see that 1 mole of 1-butanol requires 6 moles of oxygen to completely burn.
Given that the heat of combustion of 1-butanol is 2,710 kJ/mol, we can calculate the amount of 1-butanol that is required to yield 26,400 kJ of energy:
Number of moles of 1-butanol = Energy required (kJ) / Heat of combustion (kJ/mol)
Number of moles of 1-butanol = 26,400 kJ / 2,710 kJ/mol
Now, since 1 mole of 1-butanol requires 6 moles of oxygen, we can calculate the number of moles of oxygen required:
Number of moles of oxygen = Number of moles of 1-butanol * 6
Finally, to find the mass of oxygen consumed, we need to multiply the number of moles of oxygen by the molar mass of oxygen (32 g/mol):
Mass of oxygen consumed = Number of moles of oxygen * Molar mass of oxygen
Now, let's solve the problem:
Number of moles of 1-butanol = 26,400 kJ / 2,710 kJ/mol
Number of moles of 1-butanol ≈ 9.74 mol
Number of moles of oxygen = 9.74 mol * 6
Number of moles of oxygen ≈ 58.44 mol
Mass of oxygen consumed = 58.44 mol * 32 g/mol
Mass of oxygen consumed ≈ 1,877 g or 1.88 kg
Therefore, approximately 1.88 kg of oxygen is consumed when enough 1-butanol is burned to yield 26,400 kJ of energy.
To solve this problem, you will need to apply the concept of stoichiometry. Stoichiometry is a branch of chemistry that deals with the quantitative relationships between reactants and products in chemical reactions.
First, let's write the balanced chemical equation for the combustion of 1-butanol:
C4H9OH + O2 → CO2 + H2O
From the balanced equation, we can see that the stoichiometric ratio between 1-butanol (C4H9OH) and oxygen (O2) is 1:13. This means that for every 1 mole of 1-butanol, 13 moles of oxygen are required.
Given that the heat of combustion of 1-butanol is 2,710 kJ/mol, this represents the energy released per mole of 1-butanol burned.
Let's set up the equation to find the mass of oxygen consumed when 26,400 kJ of energy is released:
Step 1: Determine the number of moles of 1-butanol consumed.
Use the given heat of combustion to calculate the number of moles of 1-butanol burned:
n(1-butanol) = Energy released / Heat of combustion = 26,400 kJ / 2,710 kJ/mol
Step 2: Determine the number of moles of oxygen consumed.
Since the stoichiometric ratio between 1-butanol and oxygen is 1:13, the number of moles of oxygen consumed is:
n(O2) = 13 x n(1-butanol)
Step 3: Convert the moles of oxygen to grams.
Use the molar mass of oxygen (32 g/mol) to convert moles to grams:
mass(O2) = n(O2) x molar mass(O2)
By following these steps, you will be able to calculate the mass of oxygen consumed.