Which of the following elements has the largest atomic number?
1 answer:
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Answer : The standard enthalpy of formation of ethylene is, 52.4 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The formation reaction of will be,
The intermediate balanced chemical reaction will be,
(1)
(2)
(3)
Now we will reverse the reaction 1, multiply reaction 2 and 3 by 2 then adding all the equation, we get :
(1)
(2)
(3)
The expression for enthalpy of formation of will be,
Therefore, the standard enthalpy of formation of ethylene is, 52.4 kJ
Answer:
2, 1, 1, 4.
Explanation:
Hello there!
In this case, for the given chemical reaction:
We can see how there is one SO4 on the left and two on the right, thus, we add a 2 in front of H2SO4:
Next, since there are 8 atoms of hydrogen on the left and two on the right, we add a 4 in front of H2O to obtain:
Which is now balanced so the coefficients 2, 1, 1, 4.
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