Chemistry: Thermodynamics & Thermochemistry Flashcards
7 cards from real AP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Chemistry: Thermodynamics & Thermochemistry flashcards as text
A bomb calorimeter measures heat of combustion at constant what?
Answer: Volume
A sealed bomb calorimeter operates at constant volume, measuring ΔU.
Which statement about a catalyst's effect on thermodynamics is correct?
Answer: It does not change ΔH or ΔG
A catalyst speeds up a reaction but does not alter thermodynamic quantities like ΔH or ΔG.
For the combustion of methane, ΔH is −890 kJ/mol. Burning 0.50 mol releases how much heat?
Answer: 445 kJ
0.50 mol × 890 kJ/mol = 445 kJ released.
Which combination guarantees a spontaneous reaction at all temperatures?
Answer: ΔH 0
When ΔH is negative and ΔS is positive, ΔG is always negative.
What is heat capacity?
Answer: Heat needed to raise temperature by one degree
Heat capacity is the amount of heat required to raise a substance's temperature by one degree.
The third law of thermodynamics states the entropy of a perfect crystal at 0 K is what?
Answer: Zero
A perfect crystal at absolute zero has zero entropy because there is only one microstate.
Lattice energy, the energy released forming an ionic solid from gaseous ions, is generally what sign?
Answer: Negative (exothermic)
Forming an ionic lattice from gaseous ions releases energy, so it is exothermic (negative).