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    Chem B3. Lab - Flame Test and Emission Spectrum

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    ellamocs
    1. The document describes an experiment using flame tests and emission spectroscopy to identify unknown metal ions and gases. Students observe emission spectra through a spectroscope from various light sources and gas discharge tubes containing unknown elements. 2. They compare the line spectra to references to determine the identities of the unknown metal ions and gases. Flame tests are also used to observe characteristic colored lines emitted by heated metal salt solutions that can be used to identify unknown metal ions. 3. The experiment aims to demonstrate how emission spectroscopy can be used to act as "fingerprints" to identify elements based on the unique line spectra they emit when energized.

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    Chem B3. Lab - Flame Test and Emission Spectrum

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    ellamocs
    7 views3 pages
    1. The document describes an experiment using flame tests and emission spectroscopy to identify unknown metal ions and gases. Students observe emission spectra through a spectroscope from various light sources and gas discharge tubes containing unknown elements. 2. They compare the line spectra to references to determine the identities of the unknown metal ions and gases. Flame tests are also used to observe characteristic colored lines emitted by heated metal salt solutions that can be used to identify unknown metal ions. 3. The experiment aims to demonstrate how emission spectroscopy can be used to act as "fingerprints" to identify elements based on the unique line spectra they emit when energized.

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    1. The document describes an experiment using flame tests and emission spectroscopy to identify unknown metal ions and gases. Students observe emission spectra through a spectroscope from various light sources and gas discharge tubes containing unknown elements. 2. They compare the line spectra to references to determine the identities of the unknown metal ions and gases. Flame tests are also used to observe characteristic colored lines emitted by heated metal salt solutions that can be used to identify unknown metal ions. 3. The experiment aims to demonstrate how emission spectroscopy can be used to act as "fingerprints" to identify elements based on the unique line spectra they emit when energized.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    7 views3 pages

    Chem B3. Lab - Flame Test and Emission Spectrum

    Uploaded by

    ellamocs
    1. The document describes an experiment using flame tests and emission spectroscopy to identify unknown metal ions and gases. Students observe emission spectra through a spectroscope from various light sources and gas discharge tubes containing unknown elements. 2. They compare the line spectra to references to determine the identities of the unknown metal ions and gases. Flame tests are also used to observe characteristic colored lines emitted by heated metal salt solutions that can be used to identify unknown metal ions. 3. The experiment aims to demonstrate how emission spectroscopy can be used to act as "fingerprints" to identify elements based on the unique line spectra they emit when energized.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
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    of 3

    Unit 1: Atomic Theory

    Flame Test and Emission Spectrum

    Introduction
    If light from an incandescent bulb is passed through a prism it is separated into a rainbow of colours
    ranging from red to violet. When the light produced by passing an electric current through a gas is
    viewed in a similar manner, however, the result is quite different.
    Each gas has its own spectrum of coloured lines. In attempting to explain why gases emit line spectra,
    Neils Bohr took the concept of the atom proposed by Rutherford and developed his "solar system"
    model.

    Materials: Parts A and B


    ● Known Metal Ion Solutions ● 400 mL beaker
    ● Unknown Metal Ion Solution ● Spectroscope
    ● Bunsen burner ● Unknown Gas Discharge Tube
    ● Wooden Splints ● Pencil Crayons
    *Wear your safety glasses.

    You are expected to complete and turn in the BLUE sections of this lab

    Part A: Line Spectra of Elements

    Purpose: To observe the line spectra of unknown elements and determine using reference emission
    spectra, which elements are present in the gas discharge tubes.

    Procedure:
    1. Observe the incandescent light bulb through the spectroscope and sketch or take a picture of the
    spectrum. Record in an observation table.

    2. Point the spectroscope towards the window and sketch or take a picture of the spectrum. Record in
    an observation table.

    3. Observe the spectra produced by each of the two unknown gas discharge tubes and sketch or take a
    picture of their spectra. Record in an observation table.

    4. Compare the spectra you have drawn with the reference spectra provided to you to identify the
    unknown elements.

    Analysis:

    Observations - Design a table to collect your data. (insert pictures)

    Part B: Identifying an Unknown Metal


    Purpose: As we know from gas discharge tubes, gases can give off characteristic coloured line spectra
    when energized and looked at with a spectroscope. In this activity we will investigate the changes that
    occur to metal salts when they are heated in a Bunsen burner. The heat provides the energy for the
    electrons in the metal ion to jump to different energy levels. When those electrons drop back to their
    ground state, they emit light -the colour depends on the amount of energy released. The colours
    obtained can then be used to determine which metal ion is present in an unknown aqueous sample.

    Procedure:
    Carry out the procedure described by your teacher. Be sure to return all wooden splints to the
    appropriate container

    Analysis:
    Observations - Design a table to collect your data.

    Discussion Questions: (resource)


    1. What is the identity of the unknown metal salts and the two unknown gases?

    2. Which ion (anion or cation) is being identified using the flame test? Explain.

    3. Explain how the colors in the flame tests are produced (in terms of electrons and energy states).

    4. Street lights are yellow/orange in color and not white. Based on your flame test data, what
    gaseous element is present in street lights?

    5. Explain in your own words what a spectroscope is doing when used to view a light source.

    6. Are the spectra for the sun, the incandescent light bulb and the different gases shown
    continuous spectra or emission (line) spectra? Explain.

    7. Why are spectral lines from the bright line spectrum referred to as "fingerprints" of the atoms?

    8. What is one practical application of passing an electrical charge through a gas?


    Evaluation:

    How confident are you that your investigation produced a valid answer to the identity of the unknown
    metal salt and gases? Clearly identify two limitations of the Experimental Design. Evaluate how these
    might affect your result, and suggest realistic improvements that might address these limitations.

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