Chemistry Flashcards
7 cards from real PCAT 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 flashcards as text
The rate-determining step of a reaction is best described as:
Answer: The slowest elementary step in a mechanism
The rate-determining step is the slowest step in a reaction mechanism and controls the overall rate of the reaction.
Which of the following is a characteristic of a Lewis acid?
Answer: It accepts an electron pair
A Lewis acid is an electron pair acceptor, which is a broader definition than the Brønsted-Lowry acid definition that requires proton donation.
According to Hess's Law, the enthalpy change of an overall reaction:
Answer: Equals the sum of enthalpy changes of all steps
Hess's Law states that the total enthalpy change for a reaction is the sum of enthalpy changes for each individual step, regardless of the pathway.
Which of the following molecules has a trigonal pyramidal molecular geometry?
Answer: NH3
NH3 has a trigonal pyramidal geometry because nitrogen has three bonding pairs and one lone pair, which pushes the bonds downward.
When the pressure on a gas is doubled at constant temperature, its volume:
Answer: Is halved
According to Boyle's Law (P1V1 = P2V2), when pressure doubles at constant temperature, the volume is halved.
The process by which a solid converts directly to a gas without passing through the liquid phase is called:
Answer: Sublimation
Sublimation is the phase transition from solid directly to gas, as seen with dry ice (solid CO2) at room temperature and atmospheric pressure.
Which of the following represents a correctly balanced net ionic equation for a strong acid-strong base neutralization?
Answer: H+ + OH- → H2O
The net ionic equation eliminates spectator ions, leaving only H+ + OH- → H2O as the essential reaction between a strong acid and strong base.