Chemistry Exam 2 - Chem 255

Relates the cell potential to the reaction quotient. E = E° - (RT/nF)lnQ

Ratio of product concentrations to reactant concentrations at equilibrium.

Potential of a half-reaction under standard conditions (1 M, 1 atm, 298K).

Device converting chemical energy to electric energy (or vice versa) through a redox reaction.

Energy available to do useful work in a thermodynamic process. DG = -nFE°.

Amount of charge carried by one mole of electrons (96485 C/mol).

Chemical reaction involving a transfer of electrons between reactants.

Measures the relative amount of products and reactants present in a reaction at any given time.

Difference in electrical potential between two electrodes in an electrochemical cell.

Conditions for reactions where the pressure is 1 atm and the concentrations of the solutions are all 1M. The temperature is 298 K.

In atomic emission spectroscopy, the temperature of the flame must be stable for accurate results. This is because the signal arises from electrons dropping to lower energy levels, and a stable flame ensures consistent energy transitions.

A calibration curve is used to determine the concentration of calcium ions in a sample. The equation relating electrode voltage and calcium concentration is known as the Nernst equation.

To find the original concentration of calcium ions in an unknown solution, consider the dilution factor. The voltage reading from the ion-selective electrode is used to find the new (diluted) calcium concentration, which is then adjusted to determine the original.

The order of elution in a normal phase liquid chromatography depends on the polarity of the compounds. Less polar compounds elute first.

In normal phase chromatography, hexane elutes first (least polar), followed by benzene, and then dichlorobenzene (most polar).

Measures the concentration of a specific ion in solution.

A graph showing the relationship between an instrument's reading and a known concentration of a substance.

Solute molecules diffuse from high to low concentration regions, causing the band of separated solutes to spread.

Electrolysis is used to analyze the copper content in a bronze sample.

Separates compounds based on their specific binding to a stationary phase.

Separates compounds based on the differences in their distribution between the stationary and mobile phases.

High-performance liquid chromatography is a liquid chromatography technique with stringent specifications

A type of size-exclusion chromatography that separates materials based on size, large molecules eluting first.

Separates molecules based on their size, larger molecules eluting first. Similar to gel permeation chromatography.

Solvent choice (like ether or chloroform) impacts the separation of compounds in chromatography by influencing partition coefficients.

Pb(s) → Pb2+(aq) + 2e⁻

2H+(aq) + 2e⁻ → H2(g)

The point in a titration where the amount of titrant added is stoichiometrically equivalent to the amount of analyte.

15 mL of 0.15 M S₂O₈²⁻ reacts with 15 mL of 0.15 M I⁻.

0.197 V with respect to the standard hydrogen electrode (SHE).

Given a cell potential of 0.344 V versus SHE, the cell potential with respect to the silver-silver chloride electrode is -0.147V. Given potential of Ag/AgCl / saturated KCl electrode against SHE

Chloroform is more efficient because its partition coefficients are larger for both aspirin and salicylic acid.

Aspirin has a water solubility of 300 mL per gram and greater solubility in Chloroform and Ethyl Ether.

Process of using electric current to drive non-spontaneous chemical reactions, like reducing Cu²⁺ to Cu.

The amount of substance produced or consumed during electrolysis is directly proportional to the amount of electric charge passed through the cell.

A known substance added to a sample to help with quantitative analysis, like measuring the concentration of methyl benzoate.

The area under a peak in a chromatogram, proportional to the amount of the compound present.

A region near the interface between a metal and a solution, formed by the accumulation of charged species (ions and electrons).

The arrangement of charges, like positive and negative ions, at the surface of an electrode.

Substances that can also interact with the membrane of an ion-selective electrode, causing errors in the analysis.

A measure of the influence an interfering ion has on the potential of an ion-selective electrode.

An ion that can also be detected by an ion-selective electrode, leading to inaccurate measurements.

The Nernst equation that accounts for the interference from other ions.

The change in potential of a potassium electrode due to changes in pH.

A measure of how strongly a compound interacts with the stationary phase in chromatography.

A measure of how well two peaks in a chromatogram are separated.

A type of chromatography where the stationary phase is nonpolar and the mobile phase is polar.

Strategies to enhance the separation of peaks in a chromatogram