Carbon and hydrogen are the only two elements in a hydrocarbon. When a hydrocarbon combusts completely in excess oxygen, the products would be and . The and would come from the hydrocarbon, while the atoms would come from oxygen.
Look up the relative atomic mass of these three elements on a modern periodic table:
: .
: .
: .
Calculate the molar mass of and :
.
Calculate the number of moles of molecules in of :
.
Similarly, calculate the number of moles of molecules in of :
.
Note that there is one carbon atom in every molecule. Approximately of molecules would correspond to the same number of atoms. That is: .
On the other hand, there are two hydrogen atoms in every molecule. approximately of molecules would correspond to twice as many atoms. That is: .
The ratio between the two is: .
The empirical formula of a compound gives the smallest whole-number ratio between the elements. For this hydrocarbon, the empirical formula would be .
<span>Sulfuric acid has the highest production levels of any chemical in both the US and the world. The US alone creates 37 million tons a year. It has many uses, but one of the largest is as fertilizer.</span>
Answer : The value of for this reaction is 36.18 kJ
Explanation :
First law of thermodynamic : It states that the energy can not be created or destroyed, it can only change or transfer from one state to another state.
As per first law of thermodynamic,
where,
= internal energy of the system
q = heat added or rejected by the system
w = work done
As we are given that:
q = 38.65 kJ
w = -2.47 kJ (system work done on surrounding)
Now put all the given values in the above expression, we get:
Therefore, the value of for this reaction is 36.18 kJ