Experiment 15.1
You will be using all of the following equipment in some capacity in this lab. Select all that are applicable. -10-mL volumetric flask with a yellow plastic cap -Beaker -Erlenmeyer flask -Scintillation vials -Cuvettes -Glass pipettes -Plastic transfer pipettes -Micropipettes -Micropipette tips
10-mL volumetric flask with a yellow plastic cap, Beaker, Scintillation vials, Cuvettes, Plastic transfer pipettes, Micropipettes, Micropipette tips
The Beer's Law relationship is how we will solve for the molar absorptivity coefficient. What is the equation that translates to the linear regression format? - A = I/I0 - A = m[analyte] + b - C = Am - C = Ae
A = m[[analyte]] + b
The main purpose for Experiment 15.1 is to -Run a reaction -Determine the relationship between the concentration of Fe(NCS)^+2 and the absorbance to collect the value of molar absorption coefficient -Collect absorbances and discuss the chemical equilibrium -Solve the K value of the reaction -To use Beer's Law to calculate the wavelength needed for spectrophotometry
Determine the relationship between the concentration of Fe(NCS)^+2 and the absorbance to collect the value of molar absorption coefficient
A volumetric flask has the following characteristics: -Glassware that is designed to stand harsh conditions like extreme heat and cold -Glassware that can give volumes 3 to 4 significant figures. -Has a flat base -Can have a glass joint stopper -Can have a plastic joint stopper -Can have a metal joint stopper -Has a tare mark in the neck for the exact volume -When swirling the flask to mix a solution, only the neck must be supported
Glassware that can give volumes 3 to 4 significant figures., Has a flat base, Can have a glass joint stopper, Can have a plastic joint stopper, Has a tare mark in the neck for the exact volume
What physical property of which compound are you monitoring? -The pKa of reactant, Fe(NO3)3 -The UV/Visible absorption of the product, [Fe(NCS)]^+2 -The UV/Visible absorption of the reactant, Fe(NO3)3 -The UV/Visible absorption of the reactant, NaSCN
The UV/Visible absorption of the product, [Fe(NCS)]^+2
Micropipettes will be used in this lab. This instrument allows for more accurate volume acquisition than a graduated cylinder. -True -False
True
Molar absorptivity coefficients are dependent upon every specific reaction. -True -False
True
Le Chatelier's Principle states that -as temperature increases, the pH of a reaction also increases -as a reaction reaches equilibrium, the K values increase -a chemical reaction will spontaneously go to completion if enough energy is put into the system -a chemical reaction will always restore equilibrium when perturbed
a chemical reaction will always restore equilibrium when perturbed
Temperature is NOT a factor we will be considering this class period. However, the reaction in question is an exothermic reaction. Select all of the following conditions that will perturb the reaction to proceed in the forward direction. -adding more reactant -adding more product -adding more heat -removing heat -adding an inert gas
adding more reactant, removing heat
The spectrophotometer requires what apparatus to collect data? -cuvettes -optical fiber cable -Vernier Graphical Analysis software -Vernier Spectral Analysis software -syringes -plastic transfer pipette
cuvettes, Vernier Spectral Analysis software
This reaction can be monitored informally by the color formation because -the starting materials are mostly colorless and the the product, iron thiocyanate, is colored -the starting materials are colored and the product, iron thiocyanate, is colorless -the starting materials and the product are colored -other
the starting materials are mostly colorless and the the product, iron thiocyanate, is colored
