CHM 101/102CHM 101/102

Laboratory ManualLaboratory ManualLaboratory Manual

Atomic EmissionAtomic Emission

General Chemistry 101/102General Chemistry 101/102Laboratory ManualLaboratory Manual

University of North Carolina at WilmingtonUniversity of North Carolina at Wilmington

CHM 101/102CHM 101/102

Laboratory ManualLaboratory ManualLaboratory Manual

Atomic EmissionAtomic Emission

• PurposePurpose To use a simple spectroscope to observe the To use a simple spectroscope to observe the

emission spectra of selected elements.emission spectra of selected elements. To calculate the frequency and energy of photons To calculate the frequency and energy of photons

observed in the emission spectra of lithium, observed in the emission spectra of lithium, sodium, and copper.sodium, and copper.

• Safety ConsiderationsSafety Considerations The flame emission apparatus should be used The flame emission apparatus should be used

only in the hood.only in the hood. Immediately cleanup any spilled solutions.Immediately cleanup any spilled solutions.

CHM 101/102CHM 101/102

Laboratory ManualLaboratory ManualLaboratory Manual

Atomic EmissionAtomic Emission

• ProcedureProcedure Use the spectroscope to observe the prominent Use the spectroscope to observe the prominent

lines in the spectrum of a fluorescent lamp.lines in the spectrum of a fluorescent lamp.

point slot atpoint slot atlight sourcelight source

view hereview here

spectroscope (Boreal, Inc.)spectroscope (Boreal, Inc.) spectrum of fluorescent lampspectrum of fluorescent lamp

450 nm450 nm 570 nm570 nm

CHM 101/102CHM 101/102

Laboratory ManualLaboratory ManualLaboratory Manual

Atomic EmissionAtomic Emission

• ProcedureProcedure

NaNa LiLi CuCu

Observe the flame emission spectra for Na, Li, and Observe the flame emission spectra for Na, Li, and Cu and record the wavelength of the prominent Cu and record the wavelength of the prominent spectral line for each element.spectral line for each element.

CHM 101/102CHM 101/102

Laboratory ManualLaboratory ManualLaboratory Manual

Atomic EmissionAtomic Emission

• CalculationsCalculations

c = c =

= = cc

570 nm570 nm

== (6.63 x 10 (6.63 x 10-34-34 J·s) (5.26 x 10 J·s) (5.26 x 101414 s s-1-1))

==3.00 x 103.00 x 1088 ms ms-1-1

570 x 10570 x 10-9-9 m m5.26 x 105.26 x 101414 s s-1-1==

E = h E = h photonphoton == 3.49 x 10 3.49 x 10-19-19 J Jphotonphoton

E =E =molmol

(3.49 x 10(3.49 x 10-19-19 J) (6.02 x 10 J) (6.02 x 102323 photon) photon)photonphoton molmol

== 2.10 x 10 2.10 x 1055 J/mol J/mol

E = E = 210 kJ/mol210 kJ/molmolmol