The flame test is a procedure used by chemists to identify the presence of specified metal ions, based on the color the flame that appears along with it when it’s heated. Our flame test was in lab class, where the main aim was to tested different solid metals in the flame in order to observe the wide variety of colors those chemicals also sometimes compounds (by mixing them) they produced, the second one was to identify unknown metals based on their flame color . Based on our chemistry classes there are two ways of getting the atoms excited: a) Through heating ; example by using flame as in the flame test so the atom electrons can be induced to absorb energy and jump to an excited energy through jumps called ( Quantum Jump: This is when electrons jump to an excited state) the they get back to their ground state by emitting a photon , the amount of energy in that photon determines its color ;( red for the lowest energy of visible light, increasing energy through the rainbow of orange, yellow, green, blue, indigo, and finally violet for the highest energy of visible light.) Photons outside the visible spectrum may also be emitted, but we cannot see them as we learned before. Based on the emission spectrum of the element, the compound will turn the flame a characteristic color. This technique of using certain chemical compounds to color flames is widely used in pyrotechnics to produce the range of colors seen in a fireworks display.
b) Atomic absorption (electric discharge) : spectrometer ; by passing electric discharge : as we see the emission spectrum that shows colors of different spectrums hydrogen for example shows 4 colors …etc Materials:
1- Benson burner
2- A wire loop ( wake sure it’s clean )
3- 4 filter papers
4- 4 Unknown test solid as directed by instructor (potassium , sodium , calcium , barium / chloride )
5- A beaker
6- diluted HCL ( to clean the wire loop with it )
7- A spatula
8- Lab notebook (kept in tray under desk when conducting flame test). 9- A pencil to write what (colors, notes …etc.) you observe. Safety rules:
1- Wear lab coat at ALL times while in the classroom, or risk sitting out of the lab
2- Do not allow chemicals (i.e. HCL) to tou
ch bare skin, wash well with water immediately if you touch anything accidentally.
3- Use caution with the burner. Fire is hot.
4- Don’t stare at flame for long time.
5- Wash your hands with soap and water after handling the chemicals 6- Be cautious while being around fire , keep ur body away from it ( use your hand only) 7- Tie back hair and loose clothing.
First gather all filter papers, beaker, wire loop.. to bring back to your Lab station and set it up , Then ask your teacher to give you the four solid chemicals
Put on each filter paper a few grams* of each unknown solid -one for each paper – (*quantity: as long as it fills up the spatula) Pour diluted HCL in clean beaker
Ignite the Bunsen burner and adjust the flame so that it is as hot as possible (blue flame with light-blue inner cone) Before using the wire loop : (Dip it into the HCl solution , a) So it can catch up the solids easily
b) To remove any oxide residue that may be present. )
After that touch with your witted wire one of the unknown solids so it stick to Put the wire on the blue flame and you’ll see the metal evaporating and releasing colored flame for a couple of a minutes Quickly write down the color you observed on your note book Compare between the color you have and the named colored flames guide (Fig 1.2) your teacher have and write it’s name down After you figured out the name of your solid make a table to keep everything organized and write fill it up with your conclusions *fig.1.1 Do the last 6 steps again for each solid until your table is full (Don’t forget to Dip the tip of the wire into the HCl solution before and after every flame test you do for each metal to remove any oxide residue)
Mix between some of the metals or all and write down your observations. Make sure you got the write results be redoing the test for each metal for two extra times. Compare your results with your Lab mates to make it clear you don’t had odd conclusions. At the end turn off the Bunsen burner and rinse the loop with deionized water using a wash bottle, and then heat the loop in the hottest part of the flame until no color is imparted to the flame by the loop. Get rid of the HCL and wash any other equipment’s used.
Clean the lab station you worked on.
Important variables that may result in errors:
Any contaminated tool may result in different flame color or affect your results.
Each metal must be from the same type, when first used.
The fire heat i.e.( weak red color) may make it difficult to/affect observe the colored flames through it, so try to adjust the burner and make sure it’s flame color is blue.
We figured out the 4 unknown solid metals :
Color of the flame
The solid metal
EXPERIMENT 3 – Flame Tests & Electron Configuration [PDF] http://swc2.hccs.edu/pahlavan/intro_labs/Exp_5_Flame_Tests_and_Electron_Configuration.pdf Aidan Sterk’s Digital Portfolio : 10th Grade > chemistry Labs> Flame Test Lab https://sites.google.com/a/hightechhigh.org/aidan-sterk-s-digital-portfolio/home/10th-grade/10th-grade-chemistry-and-math/chemistry-labs/flame-test-lab Fig 1.1 : my notebook / Fig 1.2 : Google images ( Metal ion flame test )