Laboratory activity flame test
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The document describes a laboratory experiment to perform flame tests to identify elements and compounds based on the characteristic colors they emit when heated. Students will test samples of various metal salts like potassium nitrate, calcium nitrate, and lithium nitrate by placing them in a flame and observing the colors produced. The colors emitted are used to identify the elements and determine properties like the relative energy of the light.
![3. Dipthe cleanwire loopintoasampleof compound andheatthe sampleinthe burnerflame. Test
the remainingsamples,cleaningthe wire loopasdescribedinstep2, before eachnew sample is
tested. Record your observations taking note of the color imparted by the metal when being
heated.
4. Repeat the flame test for NaNO3 and KNO3 and view the flame colors produced through cobalt-
blue glass. Record your observations.
5. Askfor an unknownsaltfrom yourteacher. Performa flame teston yourunknownsalt. Record
your observations.
6. Dispose of the unused portions of your samples as directed by your teacher.
Presentation of data
Table 1 - Flame Test Results for Some Compounds [Level 5-6]
Substances
Color Imparted by the
Flame
PotassiumNitrate,KNO3
CalciumNitrate,Ca(NO3)2
StrontiumChloride SrCl2
LithiumNitrate,LiNO3
Cobalt(II) Chloride,CoCl2
SodiumNitrate,NaNO3
BariumChloride,BaCl2
Unknownsalt
1. List the compounds that produced the most easily identified colors. [Level 1-2]
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2. Which compounds are least easily identified? [Level 1-2]
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3. Which compounds produced the most intense color? [Level 1-2]
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4. The energy of colored light increases in the order red, yellow, yellow, green, and violet.
List the compounds used in the flame tests in increasing order of the energy of the light
emitted. [Level 3-4]
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Laboratory activity flame test
- 1. MENTARI INTERCULTURAL SCHOOL IB MIDDLE YEARS PROGRAM Assessment Objective: In this experiment, you will perform flame tests to identify several properties of elements and compounds. This activity would allow you to observe the colors emitted by various metals through flame tests. Introduction Have youeverwonderedwhyacandle flameisyellow?The characteristicyellow colorof acandle flame comesfromthe glowof burningcarbonfragments.The carbon fragmentsare producedby the incomplete combustion reaction of the wick and candle wax. When elements, such as the carbon fragments,are heatedtohightemperatures,someof theirelectronsare excitedtohigher energylevel. Theseexcitedelectronsthenfallbacktolowerenergylevels,releasingexcessenergy inpackagesof lightcalledphotons,orlightquanta. The color of the emittedlightdependsonits energy. Blue light is more energetic than red light, for example. When heated, each element emits a characteristic pattern of light energies, which is useful in identifying the element. The characteristic colors of light produced when substances are heated in the flame of a gas burner are the basis of flame tests for several elements. Materials 6M Hydrochloric Acid, HCl Potassium Nitrate, KNO3 Calcium Nitrate, Ca(NO3)2 Strontium Chloride SrCl2 Lithium Nitrate, LiNO3 Cobalt (II) Chloride, CoCl2 Sodium Nitrate, NaNO3 Barium Chloride, BaCl2 Unknown salt Safety goggles 1 platinum wire or nichrome wire loop 1 50-mL beaker 8 small test tubes 1 test tube rack 1 scoopula 1 gas burner/alcohol lamp Instructions 1. Use a scoopulatoplace pea-sizedsamplesof each compound intoatesttube. Place the tubesin the rack. 2. CAUTION: Hydrochloric acid is corrosive and can cause severe burns. Pour about 15 mL of 6 M HCl into a clean, labeled 50-mL beaker. Dip the wire loop intothe 6MHCl and then heat in the hot flame of the gas burner (middle part of the flame). Continue this until no color flame is emitted. Student Name: CN SY 2018 - 2019 Grade Level: 8 Date: Parent’s Signature Section: Teacher: Armand Anthony L. Galicia Formative Assessment - Laboratory Activity Unit/Topic: Flame Test
- 2. 3. Dipthe cleanwire loopintoasampleof compound andheatthe sampleinthe burnerflame. Test the remainingsamples,cleaningthe wire loopasdescribedinstep2, before eachnew sample is tested. Record your observations taking note of the color imparted by the metal when being heated. 4. Repeat the flame test for NaNO3 and KNO3 and view the flame colors produced through cobalt- blue glass. Record your observations. 5. Askfor an unknownsaltfrom yourteacher. Performa flame teston yourunknownsalt. Record your observations. 6. Dispose of the unused portions of your samples as directed by your teacher. Presentation of data Table 1 - Flame Test Results for Some Compounds [Level 5-6] Substances Color Imparted by the Flame PotassiumNitrate,KNO3 CalciumNitrate,Ca(NO3)2 StrontiumChloride SrCl2 LithiumNitrate,LiNO3 Cobalt(II) Chloride,CoCl2 SodiumNitrate,NaNO3 BariumChloride,BaCl2 Unknownsalt 1. List the compounds that produced the most easily identified colors. [Level 1-2] ---------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------- 2. Which compounds are least easily identified? [Level 1-2] ------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------- 3. Which compounds produced the most intense color? [Level 1-2] ------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------- 4. The energy of colored light increases in the order red, yellow, yellow, green, and violet. List the compounds used in the flame tests in increasing order of the energy of the light emitted. [Level 3-4] ------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------