6 + 9 = ? This is a tough question, my fellow friends...
2 answers:
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Answer:
A
Explanation:
Recall that Δ<em>H</em> is the sum of the heats of formation of the products minus the heat of formation of the reactants multiplied by their respective coefficients. That is:
Therefore, from the chemical equation, we have that:
Remember that the heat of formation of pure elements (e.g. H₂) are zero. Substitute in known values and solve for hydrazine:
In conclusion, our answer is A.
Answer : The internal energy change is -2805.8 kJ/mol
Explanation :
First we have to calculate the heat gained by the calorimeter.
where,
q = heat gained = ?
c = specific heat =
= final temperature =
= initial temperature =
Now put all the given values in the above formula, we get:
Now we have to calculate the enthalpy change during the reaction.
where,
= enthalpy change = ?
q = heat gained = 23.4 kJ
n = number of moles fructose =
Therefore, the enthalpy change during the reaction is -2805.8 kJ/mole
Now we have to calculate the internal energy change for the combustion of 1.501 g of fructose.
Formula used :
or,
where,
= change in enthalpy =
= change in internal energy = ?
= change in moles = 0 (from the reaction)
R = gas constant = 8.314 J/mol.K
T = temperature =
Now put all the given values in the above formula, we get:
Therefore, the internal energy change is -2805.8 kJ/mol