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 describes the relationship between vapor pressure and temperature?
Answer: Vapor pressure increases as temperature increases
As temperature increases, more molecules have sufficient kinetic energy to escape the liquid phase, increasing vapor pressure according to the Clausius-Clapeyron equation.
In a mass spectrometer, the molecular ion peak (M⁺) represents:
Answer: The molecule after losing one electron, giving its molecular weight
The molecular ion peak (M⁺) appears when the molecule loses one electron without fragmenting, giving a peak at the molecular weight of the compound.
Which of the following correctly describes Hess's Law?
Answer: The total enthalpy change for a reaction equals the sum of enthalpy changes for individual steps
Hess's Law states that since enthalpy is a state function, the total ΔH for a reaction is the sum of ΔH values for each step, regardless of the path taken.
Which of the following best describes a sigma (σ) bond?
Answer: A bond formed by the head-on overlap of orbitals along the internuclear axis
A sigma bond forms from head-on (end-to-end) overlap of orbitals along the internuclear axis and allows free rotation; all single bonds are sigma bonds.
What is the effect of a catalyst on an equilibrium reaction?
Answer: It lowers the activation energy of both forward and reverse reactions equally
A catalyst lowers activation energy for both the forward and reverse reactions equally, increasing the rate at which equilibrium is reached but not changing the equilibrium position or K.
Which of the following pairs are diastereomers?
Answer: Stereoisomers that are not mirror images of each other
Diastereomers are stereoisomers with the same connectivity but different spatial arrangements that are NOT mirror images of each other, such as cis-trans isomers or epimers.
Which technique would best separate and identify components of an amino acid mixture based on their charge at a given pH?
Answer: Gel electrophoresis
Gel electrophoresis separates molecules by charge and size in an electric field; amino acids migrate differently based on their net charge at the given pH (related to their isoelectric point).