alleryStart learning →What is the internal energy of a substance?
AOnly the kinetic energy of its molecules
BOnly the energy stored in its chemical bonds
CThe total of all kinds of energy present in it
DThe heat it gives out when it is fully burned
Answer & Solution
Correct answer: C. The total of all kinds of energy present in it
1. Internal energy is the total of every kind of energy present in a substance.
2. That includes translations, vibrations and rotations of its atoms and molecules.
3. Adding heat or doing work on a substance raises its internal energy.
4. Restricting it to one kind of energy only, or to combustion heat, misses most of the total.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 5 "Thermochemistry", section 5.3 Enthalpy_
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