lab 5 – emission spectra
DESCRIPTION
Lab 5 – Emission Spectra. According to Kepler’s 1 st Law a planet orbits the sun in an elliptical orbit. Where is the sun located?. On the major axis in the exact center of the ellipse. On the major axis at one of the focus points. On the minor axis halfway between the center and the orbit. - PowerPoint PPT PresentationTRANSCRIPT
Lab 5 – Emission SpectraLab 5 – Emission Spectra
According to Kepler’s 1st Law a planet orbits the sun in an elliptical orbit. Where is the sun located?According to Kepler’s 1st Law a planet orbits the sun in an elliptical orbit. Where is the sun located?
A.A. On the major axis in the exact center of the On the major axis in the exact center of the ellipse.ellipse.
B.B. On the major axis at one of the focus points.On the major axis at one of the focus points.
C.C. On the minor axis halfway between the On the minor axis halfway between the center and the orbit.center and the orbit.
D.D. At the perihelion point on the orbitAt the perihelion point on the orbit
E.E. At the aphelion point on the orbitAt the aphelion point on the orbit
Every chemical element has a unique spectral signature.Every chemical element has a unique spectral signature.A.A. TrueTrue
B.B. FalseFalse
C.C. A few elements actually have identical A few elements actually have identical emission lines.emission lines.
Light WavesLight Waves
Wavelength (Wavelength ())
Red LightRed Light – – Longer Wavelength, Lower Energy
Blue LightBlue Light – – Shorter Wavelength, Higher Energy
Color Wavelength
-e-e
Spectroscope
Prismor
Diffraction Grating
Screen
narrow slit
Narrow beam of lightWhite Light Source
Spectrum
Hot, dense gases or solids produce Hot, dense gases or solids produce a a continuous spectrumcontinuous spectrum..
Example: Light bulb filamentExample: Light bulb filament
Continuous Spectrum
Kirchhoff’s First LawKirchhoff’s First LawKirchhoff’s First LawKirchhoff’s First Law
Hot, rarefied gas produces an Hot, rarefied gas produces an emission line spectrumemission line spectrum..
Example: Neon signExample: Neon sign
Emission Line Spectrum
Kirchhoff’s Second LawKirchhoff’s Second LawKirchhoff’s Second LawKirchhoff’s Second Law
Cool gas in front of a continuous source of Cool gas in front of a continuous source of light produces an light produces an absorption line spectrumabsorption line spectrum..
Example: The SunExample: The Sun
Absorption Spectrum
Kirchhoff’s Third LawKirchhoff’s Third LawKirchhoff’s Third LawKirchhoff’s Third Law
++
Electric charge - Electrons
+ Protons
Neutrons
Nucleusprotons/neutrons
AtomsAtoms
electrons
+P+P
22
33
44
656 nm
700 nm700 nm400 nm400 nm
-e-e
Hydrogen Atom
11
-e-e
-e-e
55
-e-e
486 nm
434 nm
-e-e 410 nm
Energy LevelsEnergy Levels
Aluminum
Oxygen
Argon
Calcium
Carbon
Helium
Hydrogen
Iron
Krypton
Magnesium
Neon
Nitrogen
Sulfur
Sodium
Xenon
-e-e
How to Excite an AtomHow to Excite an AtomAbsorption of Light
White Light Source
700 nm400 nm
Hydrogen Gas
Prism
Screen
-e-e
+P+P
11
22
33
44
-e-e
656 nm
Absorption of a Photon
700 400 nm
Hydrogen Atom
White Light Source
How to Excite an Atom
-e-e
-e-e
How to Excite an Atom
+P+P
11
22
33
44
Collision with Another Particle
-e-e
Hydrogen Atom
-e-e
400 nm 500 nm 600 nm 700 nm
A
B
C
Which one of the following is an emission spectra?Which one of the following is an emission spectra?
When an electron in an atom moves from a high energy level to a lower energy levelWhen an electron in an atom moves from a high energy level to a lower energy level
A.A. a photon of light is emitted.a photon of light is emitted.
B.B. a photon of light is absorbed.a photon of light is absorbed.
C.C. the atom becomes ionized.the atom becomes ionized.
D.D. the atom gains a proton.the atom gains a proton.
The EndThe End
400 nm 500 nm 600 nm 700 nm
400 nm 500 nm 600 nm 700 nm
700 nm400 nm