Laboratory activity flame test

Laboratory activity flame test

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  MENTARI INTERCULTURAL SCHOOL IBMIDDLE 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
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  3. Dipthe cleanwireloopintoasampleof 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] ------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------