Final answer:
The value of δe for a substance that loses 26,000 joules of heat during a chemical reaction is -26,000 joules, reflecting a loss of energy from the system.
Step-by-step explanation:
The question asks us to determine the value of δe (change in internal energy) for a substance that loses 26,000 joules of heat during a chemical reaction. According to the convention in thermodynamics, when a system loses energy to its surroundings, the δe is negative. That's because the internal energy of the system has decreased. Therefore, the correct answer is -26,000 joules.