Which of the following is true for the gas phase reaction shown below? 4NH3(g) + 5O2(g) �¨ 4NO(g) + 6H2O(g), ƒ¢H = -0.905 kJ
The reaction 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) has a heat change of -0.905 kJ.
This means that the reaction is exothermic since the heat change is negative. In an exothermic reaction, energy is released as heat.
Additionally, as this is a gas phase reaction, it indicates that all the reactants and products are in the gas phase.
To determine which statement is true for the gas phase reaction 4NH3(g) + 5O2(g) -> 4NO(g) + 6H2O(g) with a heat change of -0.905 kJ, we need to consider the concepts of enthalpy and energy.
Enthalpy (ĢH) is a measure of the heat energy absorbed or released during a chemical reaction. A negative value for ĢH indicates an exothermic reaction, meaning that energy is released to the surroundings.
Now, let's analyze each statement to see which one is true:
A) The reaction is endothermic.
Since the given ĢH value is negative (-0.905 kJ), this statement is false. A negative ĢH indicates that the reaction is exothermic, not endothermic.
B) The reaction is spontaneous at all temperatures.
The ĢH value alone does not provide enough information to determine the spontaneity of a reaction. Spontaneity depends on both enthalpy (ĢH) and entropy (īS) changes. Without the īS value or further information, we cannot determine the validity of this statement.
C) The reaction releases energy to the surroundings.
Since the ĢH value is negative, this statement is true. A negative ĢH indicates an exothermic reaction, implying that energy is released to the surroundings.
Based on the analysis, the true statement is:
C) The reaction releases energy to the surroundings.