The enthalpy of reaction for the combustion of ethane 2CH₃CH₃ + 7O₂ → 4CO₂ + 6H₂O calculated from the average bond energies of the compounds is -2860 kJ/mol.
The reaction is:
2CH₃CH₃ + 7O₂ → 4CO₂ + 6H₂O (1)
The enthalpy of reaction (1) is given by:
(2)
Where:
r: is for reactants
p: is for products
The bonds of the compounds of reaction (1) are:
- 2CH₃CH₃: 2 moles of 6 C-H bonds + 2 moles of 1 C-C bond
- 7O₂: 7 moles of 1 O=O bond
- 4CO₂: 4 moles of 2 C=O bonds
- 6H₂O: 6 moles of 2 H-O bonds
Hence, the enthalpy of reaction (1) is (eq 2):

Therefore, the enthalpy of reaction for the combustion of ethane is -2860 kJ/mol.
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Answer:
I think it's B
Explanation:
I dont have much experience with the periodic table, but I just think its B.
Answer:
open system
Coffee held in a cup is an open system because it can exchange matter water vapors and energy heat with the surroundings.
Inclined planes reduce the amount of effort needed to move an object, but increases the length of the ramp.
<u>Explanation:</u>
Mechanical advantage is the measure of amount of effort needed to move an object. The mechanical advantage can be calculated as the ratio of length of ramp to the height of ramp for an inclined plane.
As it is known that an object can be easily moved on an inclined plane than on a vertical plane, this is because, the inclined plane provides greater output force. But in that case, the effort required will be reduced with the cost of increasing the distance of the movement of object.
In other terms , the ramp's length of inclined planes has to get increased in order to reduce the amount of effort needed to move an object. This is because as the mechanical advantage has length of the ramp in the numerator, with the increase in numerator value or length value the mechanical advantage will also increase.
I will say this is True….?