Given the following thermochemical equation:
NO2 (g) + O2 (g) → NO (g) + O3 (g)
ΔH = - 212 kJ
Which has more enthalpy, the reactants
NO2 (g) + O2 (g), or the products NO(g) + O3 (g) ?
The reactants have more enthalpy.
The products have more enthalpy.
The reactants and products have exactly equal enthalpy values.
This cannot be determined with the given information
Well look at the value given
a negative enthalpy means that energy was absorbed while a positive enthalpy means that energy was released
take a look at Hess' law
Enthalpy of products - Enthalpy of reactants = -212 kJ
If it's negative then that means the products are at a higher energy state (higher enthalpy) than the reactants
The given thermochemical equation indicates that the reaction is exothermic, as the enthalpy change (ΔH) is negative (-212 kJ). In an exothermic reaction, the products have lower enthalpy than the reactants. Therefore, the reactants NO2 (g) + O2 (g) have more enthalpy than the products NO(g) + O3 (g).
Therefore, the correct answer is: The reactants have more enthalpy.
To determine which has more enthalpy, the reactants or the products, we need to consider the sign and magnitude of the heat of reaction (ΔH).
In this case, the given thermochemical equation shows that the reaction is exothermic because the ΔH value is negative (-212 kJ). An exothermic reaction releases heat energy.
Reactants have higher enthalpy if the ΔH value is positive, indicating that the reaction absorbs heat energy (endothermic). Products have higher enthalpy if the ΔH value is negative, indicating that the reaction releases heat energy (exothermic).
Since the given ΔH value is negative (-212 kJ), it means that the products (NO(g) + O3(g)) have lower enthalpy than the reactants (NO2(g) + O2(g)). Therefore, the correct answer is: The reactants have more enthalpy.