Flame Test Lab Flashcards

White Light and Electromagnetic Radiation

• White light consists of a continuous spectrum with all visible light wavelengths present.
• Energy of a photon is calculated using the equation E = hv, where h is Planck's constant (6.6262 x 10^-34 J s).
• The energy difference between two electron levels results in the emission of a photon of electromagnetic radiation.

Flame Test Fundamentals

• Measurement of white light occurs between 400 nm and 700 nm (4 x 10^-7 m to 7 x 10^-7 m).
• Metals possess loosely held electrons, which contribute to their characteristic colors in flame tests.
• The color of a flame corresponds to the combination of wavelengths emitted during electron transitions.

Flame Color Production

• A colored flame is produced when electrons release energy and return to lower energy levels within an atom.
• Flame tests indicate specific energy changes occurring among electrons in metallic ions, revealing the ion's identity.
• The color resulting from a flame test is consistent for certain metallic ions regardless of the ion's source compound.

Wavelength Characteristics

• Violet light has the shortest wavelength, while red light has the longest wavelength in the visible spectrum.

Common Metallic Salts and Their Colors

• Calcium carbonate (CaCO3) is the main component of chalk.
• Barium Nitrate exhibits a pale yellow color.
• Copper (II) Chloride has a green appearance.
• Lithium Nitrate is identified by its dark red color.
• Potassium Nitrate exhibits a peach hue.
• Sodium Chloride gives a bright yellow color.
• Calcium Chloride appears orangey.
• Strontium Nitrate has a light red color.

Flame Test Process

• The process of flame tests involves atoms starting in a ground state, absorbing energy from a Bunsen burner, and electrons jumping to excited states before returning and emitting light.
• Cross-contamination in flame tests can skew results, producing a mix of colors due to combined energy level changes in different ions.

Relationship to Electromagnetic Spectrum

• The colors seen during flame tests are a combination of the visible spectrum lines produced by the metals involved.

Specific Observations

• A bright yellow flame produced when heating a glass rod indicates sodium compounds in the glass composition (75% SiO2, 25% NaO2, and CaO).
• To calculate photon energy using a wavelength, the formula E = hc/lambda is used.
• In flame tests, alternative equipment like a lighter (to provide spark/energy) and flammable materials (like alcohol) can substitute for Bunsen burners.

Applications in Fireworks

• Metallic salts in fireworks are heated, causing atoms to enter an excited state; when they return to the ground state, they emit colored light, enhancing visual effects.