How much heat is given off when 8 g of hydrogen reacts in the reaction:
\[ 2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}; \Delta H = -115.60 \text{kcal} \]
a. -57.8 kcal
b. -115.6 kcal
c. -173.4 kcal
d. -231.2 kcal
e. -462.4 kcal
Answer (2)
ΔΗ= -115.6 kJ/mol H2 has a Mr of 2, so as mol=mass/mr we can work out that there are 4 moles of H reacting
Therefore we multiply -115.6 by 4 = -462.4
When 8 g of hydrogen reacts, it releases 231.2 kcal of heat. This is determined by calculating the moles of hydrogen and multiplying by the enthalpy change of the reaction. The final answer is option d, -231.2 kcal.
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