Chemistry Flashcards
7 cards from real MCAT 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
Which of the following best explains why ionic compounds generally have high melting points?
Answer: Strong electrostatic attractions between oppositely charged ions require large amounts of energy to overcome
Ionic compounds form a crystal lattice held together by strong electrostatic forces between cations and anions, requiring substantial energy (high temperature) to disrupt.
What product is formed when an aldehyde undergoes nucleophilic addition with an alcohol?
Answer: Hemiacetal
When one equivalent of alcohol attacks the carbonyl carbon of an aldehyde, a hemiacetal is formed with both an -OH and an -OR group on the same carbon.
Which of the following is true about an enzyme at its optimal pH?
Answer: The enzyme has maximum catalytic activity
At its optimal pH, the ionization states of the enzyme's active site residues are ideal for substrate binding and catalysis, maximizing reaction rate.
A galvanic cell uses the reaction: Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s). Which statement is correct?
Answer: Zinc is oxidized at the anode
In a galvanic cell, the more active metal (zinc) is oxidized at the anode: Zn → Zn²⁺ + 2e⁻, while Cu²⁺ is reduced at the cathode.
Which of the following represents an example of a conjugate acid-base pair?
Answer: NH₃ and NH₄⁺
NH₃ and NH₄⁺ differ by a single proton (H⁺), making them a conjugate acid-base pair where NH₄⁺ is the conjugate acid of NH₃.
The rate constant of a reaction doubles when temperature increases from 25°C to 35°C. This is best explained by:
Answer: An increase in the fraction of molecules with energy exceeding the activation energy
According to the Arrhenius equation and Maxwell-Boltzmann distribution, higher temperatures shift more molecules to higher energies, increasing the fraction that can overcome the activation barrier.
Which isomers are mirror images of each other and are non-superimposable?
Answer: Enantiomers
Enantiomers are stereoisomers that are non-superimposable mirror images of each other, differing in the spatial arrangement of groups around a chiral center.