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Chem || 210 || Midterm || exam || with ||
correct || detailed || solutions
Identify || the || equivalence || point || on || the || titration || curve. Define || the || end || point || of || a || titration. || - || Correct || answer || ✔The || equivalence || point || of || a || titration || is || reached || when || the || moles || of || titrant || added || are || stoichiometrically || equal || to || the || moles || of || analyte || present || in || solution. || This || is || observed || on || the || titration || curve || as || the || point || in || the || center || of || the || steepest || part || of || the || curve, || which || correlates || to || the || greatest || concentration || (pH) || change || per || volume || of || added || titrant || for || the || titration. The || equivalence || point || of || a || titration || is || the || theoretical || result || of || a || titration, || but || what || is || actually || measured || is || the || end || point. || The || end || point || is || when || a || sudden || change || occurs || in || a || physical || property || of || the || analyte || solution || that || implies || equivalence || or || thereabouts. || A || common || example || is || the || color || change || of || an || indicator. In || the || Fajans || titration || of || Hg2+2Hg22+, || NaClNaCl || is || added || to || produce || the || precipitate || Hg2Cl2Hg2Cl2. || The || end || point || of || the || titration || is || detected || with || bromophenol || blue. What || charge || do || you || expect || the || precipitate || to || have || after || the || equivalence || point? || - || Correct || answer || ✔Negative In || the || Fajans || titration || of || Hg2+2 || with || NaCl, || the || solution || contains || excess || Hg2+2 || before || the || equivalence || point. || The || excess || Hg2+2 || adsorbs || onto || the || surface || of || the || precipitate, || imparting || a || positive || charge || onto || the || precipitate. || After || the || equivalence || point, || there || is || excess || Cl−Cl− || in || solution, || which ||
adsorbs || to || the || surface || of || the || precipitate, || imparting || a || negative || charge || onto || the || precipitate. Describe || how || the || Volhard || method || can || be || used || to || determine || the || CN−CN− || concentration || of || a || solution || by || placing || the || steps || in || the || order || they || occur. || - || Correct || answer || ✔In || the || Volhard || method, || a || known || excess || of || standard || AgNO3AgNO3 || is || added || to || the || CN−CN− || in || 0.5 || M || HNO3HNO3 || solution || while || stirring || vigorously, || resulting || in || the || precipitation || of || AgCNAgCN. Ag+(aq)+CN−(aq)⟶AgCN(s)Ag+(aq)+CN−(aq)⟶AgCN(s) Vigorous || stirring || is || required || to || prevent || excess || Ag+Ag+ || from || becoming || trapped || in || the || precipitate || as || it || forms. || The || next || step || is || to || filter || off || the || AgCNAgCN || precipitate || and || wash || it || with || dilute || HNO3HNO3. || This || step || is || required || because || AgCNAgCN || is || more || soluble || than || AgSCNAgSCN, || which || is || formed || later || in || the || titration. || If || AgCNAgCN || is || not || removed || from || the || solution, || the || end || point || will || slowly || fade || as || AgCNAgCN || redissolves || and || is || replaced || by || AgSCNAgSCN. || After || the || precipitate || is || removed, || Fe(NO3)3Fe(NO3)3 || solution || is || added || to || the || filtrate || to || give || a || concentration || of || 0.2 || M || Fe3+Fe3+. || The || excess || Ag+Ag+ || in || the || filtrate || is || then || titrated || with || a || standard || KSCNKSCN || solution. Ag+(aq)+SCN−(aq)⟶AgSCN(s)Ag+(aq)+SCN−(aq)⟶AgSCN(s) Once || all || of || the || Ag+Ag+ || has || been || consumed, || SCN−SCN− || reacts || with || Fe3+Fe3+ || to || form || a || red || complex, || which || signifies || the || end || point || of || the || back || titration.
When || the || endpoint || is || detected || by || a || dye || color || change,
- || a || cationic || dye || binds || to || the || positive || surface || of || the || precipitate.
- || - || Correct || answer || ✔The || Fajans || titration || uses || an || adsorption || indicator || to || detect || the || endpoint || of || a || titration || in || which || a || precipitate || is || formed. || For || the || titration || of || a || Cl−Cl− || solution || by || Ag+Ag+ || , || insoluble || AgClAgCl || is || formed. || Just || before || the || equivalence || point, || there || is || still || an || excess || amount || of || Cl−Cl− || in || solution. || After || the || equivalence || point, || there || is || an || excess || of || Ag+Ag+ || ions || in || solution, || which || imparts || a || positive || charge || to || the || surface || of || the || precipitate. || The || endpoint || of || the || titration || is || detcted || using || an || anionic || dye, || which || bonds || to || the || positively || charged || surface || of || the || precipitate. Sample || pretreatment || plays || an || important || role || in || gravimetric || analysis || because || the || analyte || must || meet || certain || requirements || to || be || measured || gravimetrically. What || characteristics || must || an || analyte || have || to || be || measured || using || traditional || gravimetric || analysis? able || to || be || precipitated. soluble. insoluble. in || basic || solution. in || a || mineral-based || sample. in || acidic || solution. || - || Correct || answer || ✔For || an || analyte || to || be || measured || gravimetrically, || it || must || be || in || a || form || that || is || both || soluble || and || can || be || precipitated || upon || addition || of || a || precipitant. || An || insoluble || analyte || would || not || form || a || precipitate || upon || reaction || with || a || precipitant, || so || the || analyte || needs || to || initially || be || soluble. || The || acidity || of || the || solution || during || gravimetric || analysis || is || only || important || in || how || it || affects || the || precipitation || of || the || analyte ||
and || the || precipitant. || The || analyte || can || come || from || any || sample || source || as || long || as || it || is || soluble || and || can || be || precipitated. Which || of || the || properties || are || desirable || of || a || gravimetric || analysis || precipitate? be || of || known || composition insoluble easily || filterable small || particle || size forms || a || colloidal || suspension || - || Correct || answer || ✔Ideally || a || gravimetric || analysis || precipitate || is || insoluble, || pure, || easily || filterable, || and || of || known || composition. || A || precipitate || that || is || easily || filterable || and || insoluble || is || easier || to || isolate || from || the || solution. || Larger || particles || are || preferred || over || small || ones || because || small || particles || can || clog || or || pass || through || the || filter. || Also, || large || particles || have || less || surface || areas || on || which || impurities || can || attach. || A || precipitate || that || is || pure || and || of || known || composition || can || be || used || to || quantify || the || amount || of || analyte || in || the || original || solution. A || solution || is || titrated || with || AgNO3AgNO3 || to || determine || the || Cl−Cl− || concentration. || At || the || endpoint || is || a || colloidal || suspension || of || AgClAgCl || in || a || slight || excess || of || Ag+Ag+ || and || NO−3NO3− || ions. Which || of || the || procedures || would || promote || coagulation || of || the || particles || so || that || the || precipitate || can || be || filtered || and || weighed?
- || adding || an || electrolyte || such || as || 0.1 || mol || -adding || more || NaCl || solution -adding || more || AgNO3 || solution
microwaves, || infrared, || visible || light, || gamma || rays || Highest || to || lowest || energy: || gamma || rays, || visible || light, || infrared, || microwaves Across || the || electromagnetic || spectrum, || there || are || seven || types || of || radiation. || From || lowest || to || highest || frequency, || the || types || of || radiation || are: || radio || waves, || microwaves, || infrared, || visible || light, || ultraviolet, || X-rays, || and || finally || gamma || rays. The || equation || that || shows || the || relationship || between || frequency || (𝜈ν) || and || energy || (𝐸E) || is 𝐸=ℎ𝜈E=hν where || ℎh || is || Plank's || constant. || This || equation || shows || that || energy || and || frequency || have || an || proportional || relationship. || Therefore, || the || radiation || with || the || lowest || frequency || has || the || lowest || energy, || and || the || radiation || with || the || highest || frequency || has || the || highest || energy. || In || order || from || highest || to || lowest || energy, || the || types || of || radiation || are: || gamma || rays, || X-rays, || ultraviolet, || visible || light, || infrared, || microwaves, || and || finally || radio || waves. Identify || the || statement || that || correctly || describes || the || relationship || between || wavelength || and || frequency. -Wavelength || and || frequency || are || inversely || proportional. -Wavelength || and || frequency || are || directly || proportional. -Wavelength || is || independent || of || frequency. || - || Correct || answer || ✔Wave || length || and || frequency || are || inversely || proportional.
Identify || the || statement || that || correctly || describes || the || relationship || between || wavelength || and || energy. -Energy || and || wavelength || are || inversely || proportional. -Energy || is || independent || of || wavelength. -Energy || and || wavelength || are || directly || proportional. || - || Correct || answer || ✔Energy || and || wavelength || re || inversely || proportional. Identify || the || statement || that || correctly || describes || the || relationship || between || energy || and || frequency. -Energy || and || frequency || are || directly || proportional. -Energy || is || independent || of || frequency. -Energy || and || frequency || are || inversely || proportional. || - || Correct || answer || ✔Energy || ad || frequency || are || directly || proportional. An || ultraviolet-visible || (UV-Vis) || spectrometer || is || used || to || measure..
- || vibrations || in || a || molecule || brought || about || by || certain || frequencies || of || light.
- || electronic || transitions || in || a || molecule || from || the || ground || state || to || the || excited || state.
- || rotations || in || a || molecule || brought || about || by || certain || frequencies || of || light.
Why || must || a || cuvette || be || completely || dry || before || use?
- || Excess || solvent || in || a || cuvette || can || affect || the || concentration || of || the || substance || being || studied.
- || Residual || liquid || inside || or || outside || the || cuvette || could || cause || interference || with || spectra.
- || A || spectrophotometer || is || designed || to || work || only || with || a || very || specific || volume || of || liquid || in || the || cuvette.
- || Additional || liquid || can || increase || the || pathlength || of || light || through || the || cuvette. || - || Correct || answer || ✔-Excess || solvent || in || a || cuvette || can || affect || the || concentration || of || the || substance || being || studied.
- || residual || liquid || inside || or || outside || the || cuvette || could || cause || interference || with || spectra g It || is || important || to || ensure || that || each || cuvette || is || clean || and || dry || before || use || in || a || spectrophotometric || experiment. || If || a || spectrophotometer || is || used || to || determine || the || concentration || of || a || substance, || additional || drops || of || liquid || can || dilute || the || solution || and || affect || the || results. || Also, || liquids || can || have || their || own || absorption || characteristics. || If || a || cuvette || is || not || completely || dry, || the || remaining || liquids || can || cause || unwanted || signals || in || spectra. excitation || monochromator || - || Correct || answer || ✔Typically || a || grating, || prism, || or || filter || that || selects || a || narrow || wavelength || band || of || radiation || and || passes || it || to || the || sample
Sample || cell || - || Correct || answer || ✔hold || the || sample || and || has || a || defined || path || length detector || - || Correct || answer || ✔typically || a || photomultiplier || tube || that || generates || an || electric || signal || when || struck || by || photons emission || monochromator || - || Correct || answer || ✔positioned || 90 || degrees || to || the || incident || light || and || selects || a || narrow || wavelength || band || of || radiation || to || pass || to || the || detector light || source || - || Correct || answer || ✔provides || electromagnetic || radiation || in || the || UV || or || visible || region || of || the || spectrum. reference || cuvet || - || Correct || answer || ✔houses || the || reagent || blank mirror || - || Correct || answer || ✔passes || the || beam || to || the || detector sample || cuvet || - || Correct || answer || ✔holds || the || sample || with || a || defined || pathlength amplifier || - || Correct || answer || ✔increases || the || detector || signal || for || ease || of || display || and || quantification beam || chopper || - || Correct || answer || ✔mirror || that || rotates || to || direct || light || to || either || the || sample || or || the || reference || cuvet
The || protein || apotransferrin || binds || two || Fe(III) || ions || for || cell || transport. || A || 1.50 || mL || solution || of || apotransferrin || is || titrated || with || 157 || μL || of || a || 1.53 || M || Fe(III) || solution. || The || initially || colorless || solution || turns || red || as || the || Fe(III) || is || add, || and || the || color || change || is || measured || with || a || spectrophotometer. Explain || why || there || is || a || difference || in || the || spectrophotometric || response || before || and || after || the || equivalence || point || of || the || titration. || Classify || the || statements || as || describing || the || titration || before || or || after || the || equivalence || point. Terms: -All || Fe(III) || added || will || bind || to || the || protein -no || binding || sites || are || available || for || Fe(III)
- || The || colour || change || is || minimal
- || the || colour || change || is || dramatic || - || Correct || answer || ✔Before || equivalence || point:
- || All || Fe(III) || added || will || bind || to || the || protein
- || the || colour || change || is || dramatic After || the || equivalence || point:
- || no || binding || sites || are || available || for || Fe(III)
- || the || colour || change || is || minimal
Combustion || Reaction || - || Correct || answer || ✔Reaction || in || which || a || substance || reacts || with || oxygen || gas, || releasing || energy || is || the || form || of || heat || or || gas. || Products || contain || CO2 || and || H2O. Back || titration || - || Correct || answer || ✔Excess || reagent || is || added || to || complete || the || reaction, || and || the || excess || reagent || is || then || itself || titrated. Precipitation || titration || - || Correct || answer || ✔a || precipitation || is || used || to || determine || the || concentration || of || an || unknown. most || commonly || used || to || determine || concentrations || of || anions || that || precipitate || with || the || addition || of || specific || ions. Common || ion || effect || - || Correct || answer || ✔A || change || in || the || concentration || of || either || ion || of || an || absolute || ionic || compound || will || affect || the || equilibrium, || and || therefore || the || solubility || of || the || compound the || presence || of || either || ion || will || reduce || the || solubility || by || driving || the || equilibrium || to || the || left. titrations || with || silver || ions || - || Correct || answer || ✔AG+ || forms || insoluble || solis || with || many || anions || including || CL-, || Br-, || I-, || CN-, || SCN-, || CNO-, || CO3^2- || and || S^2-. || precipitation || titration || with || silver || can || be || used || to || determine || concentration || of || these || ions. End || point || detection || is || done || using... || - || Correct || answer || ✔Volhard || or || Fajans || titration.
Two || stages || of || crstallization || - || Correct || answer || ✔nucleation || and || particle || growth nucleation || - || Correct || answer || ✔controlled || by || concentration. slow || nucleation: || keep || local || concentrations || low. dissolved || molecules || or || ions || coalesce || to || form || very || small || crystals particle || growth || - || Correct || answer || ✔very || small || crystals || grow || by || adding || more || molecules || or || ions || from || solution, || or || by || collisions || with || other || crystals. Rapid || nucleation || and || slow || particle || growth || lead || to... || - || Correct || answer || ✔slow || colloids || - || precipitates || consisting || of || very || small || crystals. || colloids || are || difficult || to || filter || d || should || be || avoided. Slow || nucleation || and || rapid || crystal || growth || lead || to... || fewer || larger || particles || (good || for || collecting || precipitate) || - || Correct || answer || ✔ Colloid || formation || can || be || avoided || by: || - || Correct || answer || ✔1. || slow || addition || of || precipitant || to || avoid || localized || supersaturation
- || rapid || stirring || to || avoid || localized || super || saturation
- || increasing || temperature || to || increase || collision || frequency || to || encourage || particle || growth
- || working || at || lower || concentrations.
homogenous || precipitation || - || Correct || answer || ✔another || strategy || for || slowing || crystal || growth. instead || of || direct || addition || of || precipitant, || a || reagent || is || added || that || slowly || decomposes || to || form || the || precipitant. Combustion || analysis || - || Correct || answer || ✔used || to || determine || the || carbon, || hydrogen, || nitrogen, || oxygen || and || Sulfur || content || of || organic || compounds. || the || sample || is || burned || in || the || presence || of || excess || oxygen, || and || the || H2O, || CO2, || N2, || and || SO2 || generated || is || collected || and || quantified. || Can || be || used || to || determine || empirical || formulas. wavelength || 380-420 || - || Correct || answer || ✔Colour || absorbed: || violet || Colour || observed: || green-yellow wavelength || 420-440 || - || Correct || answer || ✔Colour || absorbed: || violet-blue Colour || observed: || yellow wavelength || 440-470 || - || Correct || answer || ✔Colour || absorbed: || blue
wavelength || 620-680 || - || Correct || answer || ✔Colour || absorbed: || red Colour || observed: || blue-green wavelength || 680-780 || - || Correct || answer || ✔Colour || absorbed: || red || Colour || observed:green C- || speed || of || light || - || Correct || answer || ✔2.9979x10^ H || - || plancks || constant || - || Correct || answer || ✔6.62606957x10^- Visible || region || - || Correct || answer || ✔400-800nm Absorption || is || proportional || to.. || - || Correct || answer || ✔concentration || and || path || length
