Test 3 Flashcards
What is thermal energy?
- Heat.
- The kinetic energy of random motion of particles in a substance.
- Transfer involves random particle motion
What is kinetic energy?
- Work.
- Transfer involves ordered particle motion.
- Work = force X distance
What is an open system?
When both energy and matter can transfer into and out of the system.
What is a closed system?
When only energy can transfer into and out of the system.
What is an isolated system?
When neither matter nor energy can transfer into or out of the system.
What is a calorimeter?
It is an experimental approximation of an isolated system.
What does change in temperature depend on? (state changes aside)
- Amount of heat energy
- Mass of the substance
- Nature of the substance
What happens to temperature during a state change?
It remains the same until the state change is complete.
What is the energy formula?
Q = m c ΔT
In what direction does heat transfer?
Warmer objects to cooler objects.
What is the second energy formula?
- (m1 c1 ΔT1) = m2 c2 ΔT2
What is the formula to calculate final temperature?
Tf = (Ti1 m1 c1) + (Ti2 m2 c2) /
(m1 c1) + (m2 c2)
What are exothermic reactions?
Chemical reactions that release energy.
What are endothermic reactions?
Chemical reactions that absorb energy.
What are two thermochemical equations to represent exothermic reactions?
reactants —> products ΔH = -kJ
reactants —> products + kJ
