【Daily Question】Theoretical Foundation 2019.6.5
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Multiple-choice question: Which of the following statements regarding the standard enthalpy of formation of substances is incorrect? ( ) (A) The standard enthalpy of formation of elements is defined as zero under standard conditions. (B) The standard enthalpy of formation of compounds is never zero. (C) The standard enthalpy of formation of many substances cannot be measured directly through experiments. (D) The standard enthalpy of formation values for substances that are commonly used are actually relative values. Answer: A. According to the rules, the standard enthalpy of formation of the most stable element in its standard state is zero. Tip: The answer can be seen in the reply
(A) The standard enthalpy of formation of elements is defined as zero under standard conditions