Final answer:
The value of delta H is multiplied by the same number when the coefficients in a balanced chemical equation are multiplied by that number, since delta H is an extensive property that depends on the amount of substance involved.
Step-by-step explanation:
If the coefficients in a balanced equation are multiplied by a number, the value of delta H (enthalpy change) is multiplied by the same number. This is because delta H is an extensive property, which means it depends on the amount of substance involved. When we multiply the coefficients of a chemical equation, we are essentially changing the scale of the reaction, which includes the total amount of energy exchanged in the form of heat.
For instance, considering the balanced chemical equation 2H₂ + O₂ → 2H₂O, the enthalpy change for this reaction (delta H) is based on the molar amounts of reactants and products indicated by the coefficients. If the entire balanced equation were to be multiplied by a factor, say 2, resulting in 4H₂ + 2O₂ → 4H₂O, then the delta H value would also be multiplied by 2. This maintains the direct proportionality between the amount of substance and enthalpy change.