Spectral Distribution of Radiant Energy 1. 800 nm

1. X-Ray 2. UV 3. Visible light 4. IR

1. The type of spectroscopy depends on the ____ measured. 2. Normally, the quantity that is measured is an ____, either of energy absorbed or produced.

1. physical quantity 2. intensity

F1. SPECTROCHEMICAL METHODS Flashcards by Aya Nosaku

Measurements based on light and other forms of electromagnetic radiation.
Provided the most widely used tools for the
elucidation of modern atomic theory

SPECTROCHEMICAL MEHTODS

How well did you know this?

Not at all

Perfectly

any analytical method that uses light for measurement of chemical concentrations.

Spectrophotometry

How well did you know this?

Not at all

Perfectly

originally the study of the interaction between radiation and matter as a function of wavelength (λ)
historically, referred to the use of visible light dispersed according to its wavelength

Spectroscopy

How well did you know this?

Not at all

Perfectly

Light can be thought of as a?

wave or particle

How well did you know this?

Not at all

Perfectly

distance between crests
of a wave (m)

wavelength

How well did you know this?

Not at all

Perfectly

the number of oscillations per
second (Hz)

frequency

How well did you know this?

Not at all

Perfectly

Spectral Distribution of Radiant Energy

< 200 nm
200-400 nm
400-800 nm
> 800 nm

X-Ray
UV
Visible light
IR

How well did you know this?

Not at all

Perfectly

Beer-lambert law is also known as?

Beer’s law
Lambert-beer law
Beer-Lambert-Bouguer law

How well did you know this?

Not at all

Perfectly

empirical relationship that relates the absorption of light to the properties of the material through which the light is travelling.

BEER-LAMBERT LAW

How well did you know this?

Not at all

Perfectly

Beer-Lambert Law is a logarithmic dependence between?
1. ____ of light through a substance;
2. product of ____ of the substance; and
3. ____ the light travels through the material.

transmission/ transmissivity (T)
absorption coefficient
distance

How well did you know this?

Not at all

Perfectly

is a plastic ware wherein we will put a sample, and light will pass through it.

Cuvette

How well did you know this?

Not at all

Perfectly

fraction of incident light at a specified wavelength that passes through a sample.

Transmittance

How well did you know this?

Not at all

Perfectly

unitless measure of the transmittance of an optical element for a given length at a given wavelength

Optical density

How well did you know this?

Not at all

Perfectly

The type of spectroscopy depends on the ____ measured.
Normally, the quantity that is measured is an ____, either of energy absorbed or produced.

physical quantity
intensity

How well did you know this?

Not at all

Perfectly

involves interactions of matter with electromagnetic radiation, such as light.

ELECTROMAGNETIC SPECTROSCOPY

How well did you know this?

Not at all

Perfectly

Electromagnetic spectroscopy can be classified into:

Emission spectroscopy
Absorption spectroscopy
Scattering spectroscopy

How well did you know this?

Not at all

Perfectly

study of electromagnetic radiation spectra given off by atoms or molecules that undergo a transition to a lower energy level.
deals with visible light and shorter wavelengths

is less likely to happen with long wavelengths.

EMISSION SPECTROSCOPY

fluorescence/ phosphorescence

Examples of Emission spectroscopy:

fluorescence spectroscopy/ fluorometry, spectrofluorometry
flame emission spectroscopy
x-ray fluorescence spectroscopy
stellar spectroscopy

study of electromagnetic radiation spectra absorbed by atoms or molecules that change energy levels
range of the electromagnetic spectra in which a substance absorbs
used to determine the concentration of chemical compounds in samples

usually positioned between a radiation source and the observer.
specific chemical compounds have a specific absorption spectrum that acts as a

ABSORPTION SPECTROSCOPY

atoms
fingerprint

absorption of infrared radiation

Vibrational spectroscopy

technique for determining the concentration of a particular metal element in a sample

Atomic absorption

absorption of ultraviolet and visible light

UV/ Visible spectroscopy

Measures the absorption of gamma rays by atoms bound in a solid as a function of gamma-ray energy.
not an analytical technique
means to understand certain microscopic processes in matter

Mossbauer spectroscopy

subset of spectroscopy
deals with the infrared region of the electromagnetic spectrum
special use in forensic analysis in both criminal and civil cases, enabling identification of polymer degradation for example.
most widely used method of applied spectroscopy

INFRARED SPECTROSCOPY

***Infrared spectroscopy*** is widely used in **both research and industry** as a **simple and reliable technique** for

measurement quality control dynamic measurement

A reference is used for two reasons:

- **prevents fluctuations** in the output of the source affecting the data - **allows the effects of the solvent to be cancelled out**

- **measures the amount of light** that a **substance scatters** at certain **wavelengths**, **incident angles**, and **polarization angles**. - much faster than the absorption/emission process ## Footnote One of the most useful applications of light scattering spectroscopy

SCATTERING SPECTROSCOPY ## Footnote Raman spectroscopy

1. used in **condensed matter physics and chemistry** 2. to study ____, ____, & ____ modes in a system

1. raman spectroscopy 2. vibrational, rotational, & low-frequency

**Raman spectroscopy** relies on ____ or ____, of ***monochromatic light***, usually from a laser in the **visible, near infrared, or near ultraviolet range**

inelastic scattering or raman scattering

involves interactions with electron beams

ELECTRON SPECTROSCOPY

- involves inducing the **Auger effect with an electron beam**. - In this case the measurement typically ***involves the kinetic energy of the electron as variable.***

Auger spectroscopy

- involves the **interaction of charged species with magnetic and/or electric fields**, giving rise to a mass spectrum. - determination of the **elemental composition of a sample or molecule** - also used for **elucidating the chemical structures of molecules**

MASS SPECTROMETRY

consists of ***ionizing chemical compounds*** to **generate charged molecules or molecule fragments** and **measurement of their mass-to-charge ratios** ## Footnote calculated from the **motion of the ions** as they transit through electromagnetic fields.

MS principle ## Footnote mass-to-charge ratio

***MS instruments*** consist of three modules: 1. **splits** the sample molecules into ions 2. **sorts** the ions **by their masses** by applying electromagnetic fields 3. **measures the value of an indicator quantity** and thus **provides data for calculating the abundances** of each ion present ## Footnote [has both qualitative and quantitative uses] these include?

1. source 2. mass analyzer 3. detector ## Footnote 1. identifying **unknown compounds** 2. determining the **isotopic composition** of elements in a molecule 3. determining the **structure of a compound** by observing its fragmentation

other uses of MS?

1. quantifying the **amount of a compound** in a sample 2. studying the **fundamentals of gas phase ion chemistry** (the *chemistry of ions and neutrals in a vacuum*)

involves the frequency of **sound**

Acoustic spectroscopy

involves the frequency of an **external electrical field**

Dielectric spectroscopy

involves the frequency of an **external mechanical stress**, e.g. a torsion applied to a piece of material

Mechanical spectroscopy

- **quantifiable study of electromagnetic spectra** - **more specific than the general term** electromagnetic spectroscopy - deals with ***visible light, near ultraviolet, and near-infrared***

SPECTROPHOTOMETRY

is **a photometer** (a device for measuring light intensity) that can measure **intensity** as a ***function of the color***, or more specifically, ***the wavelength***

spectrophotometer