Chem 209 quiz 2 - Study guides, Class notes & Summaries

CHEM 209 Quiz 2 Latest Update Graded A+ Question: What is the chemical equation representing the reaction between Fe3+ and thiocyanate? - a. SCN-(aq) + Fe3+(aq) = Fe(SCN)2+(aq) - b. Fe3+(aq) + SCN-(aq) = Fe(SCN)2+(aq) - c. Fe(SCN)2+(aq) = SCN-(aq) + Fe3+(aq) - d. Fe(SCN)2+(aq) = Fe3+(aq) + SCN-(aq) - Answer: b. Fe3+(aq) + SCN-(aq) = Fe(SCN)2+(aq) Explanation: This equation shows the formation of the complex ion Fe(SCN)2+ from Fe3+ and thiocyanate ions. Question: Provide the...

Calculate the absorbance A of solutions whose percent transmittance is measures as 5%, 10%, 50%, and 100%. - Answers-A=-log(T) 1.3, 1.0, .30, and 0 respectively Give the block diagram of a visible spectrophotometer, illustrating the major components of the instrument in the correct sequence. - Answers-[Light source] ---many lambdas---> [Monochromator] --- one lambda---> [Sample cell] ---I---> [Photodetector] ------> [Readout] It is important that Kf for FeSCN2+ has a large valu...

Chem 209 Quiz Questions Quiz 3 Latest Update Graded A+ Question: Provide a block diagram of a GC instrument, indicating all essential components. - a. Sample Injector, Mobile Phase Reservoir, Detector, and Read-out - b. Mobile Phase, Sample Port, Detector, and Output - c. Solvent Reservoir, Injector, Moving Phase, Sensor, and Display Answer: a. Sample Injector, Mobile Phase Reservoir, Detector, and Read-out Explanation: This diagram outlines the fundamental components of a Gas ...

CHEM 209 Quiz 1 Latest Update Graded A+ Question: What is a back titration? - a. A method where excess titrant is added first and then the remaining is titrated - b. A titration where the initial solution is known and the excess is titrated carefully - c. A technique involving titration with a known excess of titrant, followed by titration of the excess - Answer: c. A technique involving titration with a known excess of titrant, followed by titration of the excess Explanation...

CHEM 209: QUIZ 1 with Complete and Verified Answers 1. What is a "back titration"? Answer: It's a technique where the concentration of an analyte is determined by reacting it with an excess of a known reagent. 2. What is the balanced chemical equation for the complete reaction between CO32− and HCl? Answer: CO32−(aq) + 2H+(aq) → H2O(l) + CO2(g) 3. What is the balanced chemical equation for the complete reaction between KHP (KHC8H4O4) and NaOH? Answer: KHC8H4O4(aq...

CHEM 209 Quiz 3 Latest Update with Verified Solutions Provide a diagram illustrating the key components of a GC instrument. Answer: Reservoir for Mobile Phase (pressurized helium cylinder) -> Oven -> Sample Injector (micro-syringe) -> Stationary Phase (column) -> Detector (thermal conductor or flame ionization detector) -> Readout (computer) What variables are typically plotted on the x- and y- axes of (a) a chromatogram and (b) a calibration curve? a. x: time, y...

What is the balanced chemical reaction of Fe3+ with thiocyanate? -️️SCN-(aq) + Fe3+(aq) = Fe(SCN)2+(aq) Show the equation for Beer's Law and define all the terms (including units) - ️️A=Ebc A= Sample's measured absorbance E= molar absorptivity at the wavelength used (L/(mol x cm) b= width of sample (cm) c= sample concentration (M) What is the lambda max, how is it determined, and why are absorption measurements such as those in this experiment made at this lambda? - ️️Lambd...

CHEM 209 Quiz 3 Latest Version with Complete Solutions What variables are typically plotted on the x- and y-axes of a chromatogram? x-axis: time, y-axis: response What variables are typically plotted on the x- and y-axes of a calibration curve? x-axis: concentration, y-axis: peak area What term describes the time it takes for a molecule to move through the column? retention time What term describes the material coating the inside of the column in chromatography? stationary...

Zn -️️zinc Ge - ️️germanium As - ️️arsenic Br - ️️bromine Kr - ️️krypton Sr - ️️strontium Ag - ️️silver Cd - ️️cadmium