Instrumentation Flashcards
(113 cards)
What is Beer’s Law?
Beer’s Law states that the absorbance of a solution is directly proportional to its concentration and the path length of the light.
True or False: Beer’s Law can be expressed mathematically as A = εlc.
True
In the equation A = εlc, what does ‘A’ represent?
‘A’ represents the absorbance of the solution.
Fill in the blank: In Beer’s Law, ‘ε’ is the _____ coefficient.
molar absorptivity
What factors can affect the validity of Beer’s Law?
Concentration, wavelength, and the presence of other absorbing species can affect the validity of Beer’s Law.
Multiple Choice: Which of the following is NOT a requirement for Beer’s Law to hold true? A) Monochromatic light B) Constant temperature C) Infinite concentration D) Homogeneous medium
C) Infinite concentration
What is the relationship between absorbance and concentration according to Beer’s Law?
Absorbance increases linearly with an increase in concentration.
True or False: Beer’s Law can be applied to all types of solutions regardless of concentration.
False
What does the term ‘path length’ refer to in the context of Beer’s Law?
Path length refers to the distance that light travels through the solution.
How is the molar absorptivity coefficient ‘ε’ defined?
‘ε’ is defined as the absorbance per unit concentration per unit path length.
What is flame photometry used for?
Flame photometry is used for the quantitative determination of certain metal ions based on their emission of light when heated in a flame.
True or False: Atomic absorption spectrophotometry measures the light emitted by atoms.
False. Atomic absorption spectrophotometry measures the light absorbed by atoms.
Fill in the blank: In flame photometry, the sample is typically introduced into the flame in the form of a ______.
solution
What is the primary component of an atomic absorption spectrophotometer?
A light source, usually a hollow cathode lamp, specific to the element being analyzed.
Which technique is more sensitive for trace metal analysis: flame photometry or atomic absorption spectrophotometry?
Atomic absorption spectrophotometry is more sensitive for trace metal analysis.
What is the principle behind fluorometry?
Fluorometry is based on the measurement of emitted light from a sample after it has absorbed light of a specific wavelength.
Multiple Choice: Which of the following elements is commonly analyzed using flame photometry? A) Iron B) Sodium C) Mercury D) Lead
B) Sodium
True or False: Fluorometry can be used to measure concentrations of fluorescent compounds in a sample.
True.
What is the main advantage of using atomic absorption spectrophotometry?
High sensitivity and the ability to analyze trace elements.
Fill in the blank: Flame photometry primarily measures _______ emission.
light
What type of flame is typically used in flame photometry?
A natural gas or air flame.
Multiple Choice: Which of the following instruments can be used for quantitative analysis? A) Spectrophotometer B) pH meter C) Thermometer D) Refractometer
A) Spectrophotometer
True or False: Atomic absorption spectrophotometry requires a solid sample.
False. It typically requires a liquid sample.
What is the role of the nebulizer in flame photometry?
To convert the liquid sample into an aerosol for introduction into the flame.