1. What is thermal energy? ( 1 point) a. the average overall volume of a system
b. the total number of molecules in a system
c. the kinetic energy of particles in a system
d. the measure of temperature in a system
2. heat that flows by conduction is the transfer of thermal energy between substance in contact. What must occur for this to happen?
a. the two systems must be the same temperature
b. the two systems must not be touching each another
c. one system must have kinetic energy that the other system
d. the thermal energy of one system must be the same as the thermal energy of the other system
3. Iron reacts with oxygen in a chemical hand warmer. How should this reaction be categorized?
a. as an exothermic process because it releases heat
b. as an endothermic process because it releases heat
c. as an exothermic process because it absorbs heat
d. as an endothermic process because it absorbs heat
4. Which event is endothermic?
a. the burning of a match
b. the change of water vapor into liquid
c. the combustion of propane gas
d. the melting of ice
5. In what type of reaction or process does heat flow into the system?
a. combustion
b. exothermic
c. condensation
d. endothermic