When 13.0 g of acetylene, C2H2, undergoes complete combustion, 65.5 kJ of heat are released.
a) How much energy is released when one mole of acetylene is burned?
b) Write a balanced chemical equation for the reaction and include the heat value in the equation.
Mass of one mol C2H2
= 2*12 + 2 = 26 grams/mol
(26/12) * 65.5 =131 kJ
xC2H2 + (.5 x+2x)O2 ===> 2xCO2 + x H2O
so try x = 2
2 C2H2 + 5 O2 ===> 4 CO2 + 2 H2O that works :)
typo
26/13 I mean
To calculate the amount of energy released when one mole of acetylene is burned, we need to convert the given mass of acetylene to moles.
a) The molar mass of acetylene (C2H2) is calculated as follows:
Molar mass of carbon (C) = 12.01 g/mol
Molar mass of hydrogen (H) = 1.01 g/mol
Molar mass of acetylene (C2H2) = 2 * molar mass of carbon + 2 * molar mass of hydrogen
= 2 * 12.01 g/mol + 2 * 1.01 g/mol
= 26.04 g/mol
Now, we can calculate the amount of energy released per mole of acetylene by dividing the given energy release by the molar mass of acetylene.
Energy released per mole of acetylene = 65.5 kJ / (26.04 g/mol)
= 2.514 kJ/g
Therefore, when one mole of acetylene is burned, 2.514 kJ of energy is released.
b) The balanced chemical equation for the combustion of acetylene can be written as follows:
C2H2 + 5/2 O2 -> 2 CO2 + H2O + 65.5 kJ
In this equation, C2H2 is acetylene, O2 is oxygen, CO2 is carbon dioxide, H2O is water, and 5/2 is the stoichiometric coefficient to balance the equation. The heat value (65.5 kJ) is included on the product side of the equation.
To calculate the energy released when one mole of acetylene is burned, you need to determine the molar mass of acetylene (C2H2). Here's how you can get the answer:
a) Calculate the molar mass of acetylene (C2H2):
The atomic mass of carbon (C) is approximately 12.01 g/mol.
The atomic mass of hydrogen (H) is approximately 1.01 g/mol.
Since acetylene has two carbon atoms and two hydrogen atoms, the molar mass of acetylene can be calculated as:
(2 * 12.01 g/mol) + (2 * 1.01 g/mol) = 26.04 g/mol
Now, you have the molar mass of acetylene, which is 26.04 g/mol.
To determine the energy released when one mole of acetylene is burned, divide the given energy (65.5 kJ) by the molar mass of acetylene:
(65.5 kJ) / (26.04 g/mol) = 2.515 kJ/g
So, when one mole of acetylene is burned, approximately 2.515 kJ of energy is released.
b) The balanced chemical equation for the complete combustion of acetylene (C2H2) is:
2C2H2 + 5O2 -> 4CO2 + 2H2O
(Note: This equation is already balanced)
The heat value, 65.5 kJ, can be included as a reactant or a product in the equation to indicate the energy released during the combustion. For example, you could write the equation as:
2C2H2 + 5O2 -> 4CO2 + 2H2O + 65.5 kJ
This indicates that when two moles of acetylene react with five moles of oxygen, they produce four moles of carbon dioxide, two moles of water, and release 65.5 kJ of heat.