Name: Peter Fisher
Partner's Name: Daniela Garcia
Date: September 25th, 2014
Partner's Name: Daniela Garcia
Date: September 25th, 2014
FLAME TEST
PURPOSE
Observe how different elements produce differently colored flames when set alight, due to the energy released from their electrons' quantum jumps. Identify these elements by means of the colors produced in their flames.
PROCEDURE
PRE-LAB QUESTIONS
1. What color of light is the lowest in energy?
Red light has the lowest energy.
2. What color of light is the highest in energy?
Violet light has the highest energy.
3. What color of light is the highest frequency?
Violet light has the highest frequency.
4. What color of light is the lowest frequency?
Red light has the lowest frequency.
5. Explain "ground state."
An electron's ground state is the shell in which it has the lowest energy. It will make a temporary quantum jump out of this ground state when excited, but it will always return to this state of lowest energy.
6. How are electrons "excited?"
An electron is excited by absorbing energy, though quanta such as photons, or through heat.
7. What does it mean when the electrons are "excited?"
The electrons have gained energy, and made a quantum jump - in other words, teleported - to a shell in which they can make a wave path around the nucleus with increased energy.
8. In your own words, write a short explanation of how an electron absorbs energy and re-
emits it as light and why different elements have different spectra.
A photon hits an electron and imports energy. The electron makes a temporary quantum jump, but must eventually release its added energy in the form of a photon of a specific wavelength. This wavelength will differ from element to element because every element has its own unique electron configuration, and therefore will have different shells available in different spots in the atom.
DATA TABLES AND OBSERVATIONSCompound Name Formula Flame Color
Methanol CH4O transparent indigo, with some orange sparks
Lithium Chloride LiCl magenta-red (close to a luminescent pink)
Calcium Chloride CaCl2 orange
Sodium Chloride NaCl pure orange
Calcium Carbonate CaCO3 transparent indigo
Magnesium Sulfate MgSO4 blue
Potassium Chloride KCl orange with white and yellow sparks
Sodium Borate Na2B4O7 green flash, then pure orange
Copper Sulfate CuSO4 indigo with some orange and red sparks
Strontium Chloride SrCl2 red
Copper Chloride CuCl2 fizzling green and blue, with orange sparks
Unknown #1 ??? orange with a green tint
Unknown #2 ??? green, blue, and white with orange sparks
CONCLUSION
Each compound, when mixed with the alcohol methanol for flammability, produced a uniquely colored flame. The flames were visible because they were producing photons rather than reflecting them; the flames were colored uniquely because each flame, as a result of its compound, was producing photons - quanta of energy - of a specific wavelength, or with a certain amount of energy.
DISCUSSION OF THEORY
Knowledge of color theory is essential for an analysis of this experiment's results. Essentially, all colors are made up of any combination of three primary colors: red, green, and blue. A combination with the ratio of 1:1 of red and green will produce yellow, green and blue will produce cyan, and blue and red will produce magenta. All three combined will produce white. This is involved with analysis of the experiment in multiple ways. The simplest is determining what compounds are in each unknown compound. For example, Unknown #2 had a white color in its flame, which wasn't a part of any of the other tested compounds, but color theory tells us that white is comprised of red, green, and blue. Since green and blue were represented elsewhere in the flame, the white color must have resulted from a combination of those two and red. This helped my partner and me identify Strontium Chloride in the mixture. It can also be involved in more complicated ways. For example, one might wonder where an orange color comes from, when there are two different elements in a compound. Color theory tells us that orange is made of red and yellow, which in turn is made of red and green. So, either one element burns red and one burns yellow, or one burns red more strongly than the other, which burns green.
ERROR ANALYSIS
A failure to dissolve the compounds in the methanol properly would result in a flame more influenced by the methanol than by the compound. Some results, such as the flame colors for Calcium Carbonate, Magnesium Sulfate, and Copper Sulfate, were unexpectedly close to the flame color of methanol, and this may or may not have been a result of unsuccessful mixing. It is very difficult to tell whether this is the case or not for these elements, but it would be the most probable source of error in the experiment.
RESPONSES TO POST LAB QUESTIONS AND CHALLENGE EXTENSIONS
1. Why is it important to test he flame color of the methanol without any compounds
dissolved in it?
It's important to set the methanol aflame without anything dissolved in it because the methanol is a control; it's meant to be compared to the compounds' flames. A compound might burn pure orange, but one won't know whether that's the compound or the methanol unless the methanol's flame has already been observed.
2. List the colors observed in this lab from highest energy to lowest energy.
Indigo has the highest energy. Then, there is blue, green, orange, red, and a vivid pink, in order from highest to lowest energy.
3. List the colors observed in this lab from highest frequency to lowest frequency.
Higher frequency means higher energy, so again the list is indigo, blue, green, orange, red, and pink, from highest to lowest.
4. List the colors observed in this lab from shortest wavelength to longest wavelength.
Again, the list would be indigo, blue, green, orange, red, and pink, since shorter wavelength means higher frequency.
5. What is the relationship between energy, frequency, and wavelength?
There are two equations: E = h v, and c = λ v. The first equation shows that energy and frequency (v) are directly proportionate, and the second shows that frequency and wavelength (λ) are inversely proportionate. Substitution gives E = h c / λ. meaning that energy and wavelength are inversely proportionate as well.
6. Based on the results of your experiments, what metal was found in your unknowns?
Explain.
Unknown #1 had orange and green tints to its flame, leading us to believe that it was Sodium Borate, which had an orange flames beginning with a green flash. It's metal was Sodium. Unknown #2 burned with a blue, green, and white flame with orange sparks. We identified Copper Chloride by its blue color before it was mixed with methanol and lit, and the presence of a white color indicates the presence of red as well as green and blue. Strontium Chloride was the only compound with a red flame, so that must have been the other component. It's metals were Copper and Strontium.
7. Do you think we can use the flame test to determine the identity of unknown in a
mixture? Why or why not?
Yes, it is possible, but not with the naked eye, since different elements may give off wavelengths that differ by a few nanometers. Scientists actually use satellites to determine the chemical composition of stars and planets based off of their emissions.
8. Why do different chemicals emit different colors of light?
Different elements have different numbers of differently shaped orbitals, and the electrons necessarily require different amounts of energy to make quantum jumps between these orbitals.
9. Why do you think the chemicals have to be heated in the flame first before the colored
light is emitted?
Heat is just transfer of energy; when heat is applied to the electrons, they are taking in energy, but only in the specific amounts required to make quantum jumps. They must re-emit that energy of photons of a specific wavelength.
10. Most salts contain a metal and a non-metal. Look at the compounds we tested and
explain how we can be sure that it is the metal atoms that are responsible for the colors
that you see.
There are many salts containing Chlorine and a metal (e.g. Sodium Chloride, Strontium Chloride, and Copper Chloride). One common color between mots of these is orange, found either in the color of the flame or in sparks, but most of them also have their own distinctive, prevailing colors, which leads to the conclusion that the metals show their colors more than the non-metals.
11. Colorful light emissions are applicable to everyday life. Where else have you observed
colorful light emissions? Are these light emission applications related? Explain.
Colorful light emissions are seen on LCD screens every day by many of us. These screens are comprised of red, green, and blue pixels, and these pixels light up in various combinations of the three colors to create the variety seen on your laptop. That's color theory at work! However, LCD pixels do not require elements to emit their specific photon wavelengths. They are simply florescent lights behind, among other things, a liquid crystal that will only let red, green, or blue light through it and will darken if electric current is run through it, so this is not very related to the experiment. More closely related are "neon" lights which are so common above stores and hotels (actually, they used to be more common than they are now). Neon is in quotations because, although this is the most famously used gas in these signs, Neon only burns red. To get another color of light, one needs to burn a different element.
12. Can you think of a way in which to use the flame test? Please describe below.
I can think of similar applications in the field of science. For example, scientists can discover the chemical composition of a planet's atmosphere, a star, or a nebula just by looking at a picture taken by a deep-space telescope and analyzing the emitted light. Because each element gives off its own wavelength, scientists can tell which unreachable 13,000-light-year-away planets could sustain life.
13. What professionals would use this type of information?
Firefighters might find the information from the Flame Test useful, as suggested by question 15, so that they can know exactly what they are dealing with. Forensic specialists might also find the information useful, potentially, so that they could identify certain elements in a crime scene clue. Geologists, paleontologists, or archeologists might find it useful for similar reasons. Finally, astronomers/astrophysicists would also find the information useful, because of the application described in the answer to question 12.
14. Why is the Statue of Liberty green?
The Statue of Liberty is green because it is made of copper, which is ordinarily metallic and golden-brown, but which oxidizes in air, becoming green. On contact with oxygen, copper's electron configuration will change, and the energy of the emitted photons will change accordingly, from golden-brown to green.
15. Suppose you were a firefighter and you were called to a chemical plant fire. Upon arriving,
you see a bright violet/purple flame. What chemical would you know is burning?
Methanol has an indigo flame, which is very close to violet. Any number of compounds might be mixed in to make a methanol-based flame change color from indigo to violet. Color theory tells us that all that's needed is a very small amount of red color.
16. Using the information in your data table, design a fire works display that transitions
between four different colors. Explain what is happening.
One might not only create a firework display using four different colors, but incorporate four different colors into one firework! It's easy. A firework has multiple "stars," which are comprised of a fuel, oxidizer, metal powder, binder, and element to add color. These stars are what you actually see in the sky; they're set alight when the firework detonates, and the color compounds in them burn. A firework can have as many or as few stars as one can fit inside the shell, and the only limit on shell size is what one can launch in a mortar tube. I could, for example, build a firework with 40 stars. I'll give them all fuel, oxidizer, and iron powder to add brightness when they burn. Then, I'll add Strontium Chloride to ten, Sodium Chloride to ten, Barium Chloride to ten, and Copper Chloride to ten. That will make ten red, ten yellow-orange, ten green, and ten turquoise when they burn.
17. Research some information about the origin of fireworks. Explain how they are made,
what chemicals are used, what colors they burn and their uses.
Black powder, the result of mixing charcoal, sulphur, and saltpeter, originated in China approximately 2,000 years ago. 1,000 years after that, the Chinese monk Li Tian invented the firecracker. After being brought to Europe by Marco Polo (by most accounts), black powder was used in guns, rockets, and cannons. Fireworks first appeared in Italy, but were quickly adopted by Germany. After a while, England became fascinated with the projectiles. ("History of Fireworks." Phantom Fireworks. N.p., n.d. Web. 27 Sept. 2014.) A firework shell is launched from a mortar, with a small bursting charge that will both propel the shell out of the tube and light its fuse. Once the fuse has burned down completely, a bursting charge inside will explode with two effects. The first effect is to propel several stars in all directions. The second effect is to light those same stars, creating extremely bright and colorful globes hurtling in all directions. Brain, Marshall. "How Fireworks Work." HowStuffWorks. HowStuffWorks.com, n.d. Web. 28 Sept. 2014. Many chemicals are used to add color to fireworks, including (in order from red to violet) Strontium, Lithium, Sodium, Barium, Copper, and Magnesium or Iron (white). "How Firework Colors Work." About. N.p., n.d. Web. 28 Sept. 2014.
18. Determine the wavelength of any two of the elements that you observed. Calculate the
frequencies (c=wavelength x frequency) and the energy (E = hf) for each. Make a table of
your results with the following columns: 1: wavelength in meters, 2: frequency in Hz, 3:
Energy in J. List the results in order form the lest energetic to the most energetic photons.
Element Wavelength (m) Frequency (Hz) Energy (J)
Strontium 6.5 x 10^-7 m 4.62 x 10^14 Hz 3.048 x 10^-19 J
Copper 4.75 x 10^-7 m 6.32 x 10^14 Hz 4.188 x 10^-19 J
Observe how different elements produce differently colored flames when set alight, due to the energy released from their electrons' quantum jumps. Identify these elements by means of the colors produced in their flames.
PROCEDURE
- Begin control - add 10 drops of methanol to a watch glass.
- Strike a match and carefully light the methanol.
- Observe the color of the methanol's flame - end control.
- Obtain a small amount of the first compound from Ms. Parsons in a clean, dry watch glass.
- Add 10 drops of methanol, or however much is needed to dissolve the compound, and stir carefully with a clean, dry glass stir rod until compound is dissolved.
- Strike a match and carefully ignite the rim of methanol surrounding the dissolved compound.
- Observe and record the color of the flame produced by the compound.
- Repeat steps 2 - 5 until all compounds have been tested.
- Clean and put away all supplies, clean tables, and wash hands.
PRE-LAB QUESTIONS
1. What color of light is the lowest in energy?
Red light has the lowest energy.
2. What color of light is the highest in energy?
Violet light has the highest energy.
3. What color of light is the highest frequency?
Violet light has the highest frequency.
4. What color of light is the lowest frequency?
Red light has the lowest frequency.
5. Explain "ground state."
An electron's ground state is the shell in which it has the lowest energy. It will make a temporary quantum jump out of this ground state when excited, but it will always return to this state of lowest energy.
6. How are electrons "excited?"
An electron is excited by absorbing energy, though quanta such as photons, or through heat.
7. What does it mean when the electrons are "excited?"
The electrons have gained energy, and made a quantum jump - in other words, teleported - to a shell in which they can make a wave path around the nucleus with increased energy.
8. In your own words, write a short explanation of how an electron absorbs energy and re-
emits it as light and why different elements have different spectra.
A photon hits an electron and imports energy. The electron makes a temporary quantum jump, but must eventually release its added energy in the form of a photon of a specific wavelength. This wavelength will differ from element to element because every element has its own unique electron configuration, and therefore will have different shells available in different spots in the atom.
DATA TABLES AND OBSERVATIONSCompound Name Formula Flame Color
Methanol CH4O transparent indigo, with some orange sparks
Lithium Chloride LiCl magenta-red (close to a luminescent pink)
Calcium Chloride CaCl2 orange
Sodium Chloride NaCl pure orange
Calcium Carbonate CaCO3 transparent indigo
Magnesium Sulfate MgSO4 blue
Potassium Chloride KCl orange with white and yellow sparks
Sodium Borate Na2B4O7 green flash, then pure orange
Copper Sulfate CuSO4 indigo with some orange and red sparks
Strontium Chloride SrCl2 red
Copper Chloride CuCl2 fizzling green and blue, with orange sparks
Unknown #1 ??? orange with a green tint
Unknown #2 ??? green, blue, and white with orange sparks
CONCLUSION
Each compound, when mixed with the alcohol methanol for flammability, produced a uniquely colored flame. The flames were visible because they were producing photons rather than reflecting them; the flames were colored uniquely because each flame, as a result of its compound, was producing photons - quanta of energy - of a specific wavelength, or with a certain amount of energy.
DISCUSSION OF THEORY
Knowledge of color theory is essential for an analysis of this experiment's results. Essentially, all colors are made up of any combination of three primary colors: red, green, and blue. A combination with the ratio of 1:1 of red and green will produce yellow, green and blue will produce cyan, and blue and red will produce magenta. All three combined will produce white. This is involved with analysis of the experiment in multiple ways. The simplest is determining what compounds are in each unknown compound. For example, Unknown #2 had a white color in its flame, which wasn't a part of any of the other tested compounds, but color theory tells us that white is comprised of red, green, and blue. Since green and blue were represented elsewhere in the flame, the white color must have resulted from a combination of those two and red. This helped my partner and me identify Strontium Chloride in the mixture. It can also be involved in more complicated ways. For example, one might wonder where an orange color comes from, when there are two different elements in a compound. Color theory tells us that orange is made of red and yellow, which in turn is made of red and green. So, either one element burns red and one burns yellow, or one burns red more strongly than the other, which burns green.
ERROR ANALYSIS
A failure to dissolve the compounds in the methanol properly would result in a flame more influenced by the methanol than by the compound. Some results, such as the flame colors for Calcium Carbonate, Magnesium Sulfate, and Copper Sulfate, were unexpectedly close to the flame color of methanol, and this may or may not have been a result of unsuccessful mixing. It is very difficult to tell whether this is the case or not for these elements, but it would be the most probable source of error in the experiment.
RESPONSES TO POST LAB QUESTIONS AND CHALLENGE EXTENSIONS
1. Why is it important to test he flame color of the methanol without any compounds
dissolved in it?
It's important to set the methanol aflame without anything dissolved in it because the methanol is a control; it's meant to be compared to the compounds' flames. A compound might burn pure orange, but one won't know whether that's the compound or the methanol unless the methanol's flame has already been observed.
2. List the colors observed in this lab from highest energy to lowest energy.
Indigo has the highest energy. Then, there is blue, green, orange, red, and a vivid pink, in order from highest to lowest energy.
3. List the colors observed in this lab from highest frequency to lowest frequency.
Higher frequency means higher energy, so again the list is indigo, blue, green, orange, red, and pink, from highest to lowest.
4. List the colors observed in this lab from shortest wavelength to longest wavelength.
Again, the list would be indigo, blue, green, orange, red, and pink, since shorter wavelength means higher frequency.
5. What is the relationship between energy, frequency, and wavelength?
There are two equations: E = h v, and c = λ v. The first equation shows that energy and frequency (v) are directly proportionate, and the second shows that frequency and wavelength (λ) are inversely proportionate. Substitution gives E = h c / λ. meaning that energy and wavelength are inversely proportionate as well.
6. Based on the results of your experiments, what metal was found in your unknowns?
Explain.
Unknown #1 had orange and green tints to its flame, leading us to believe that it was Sodium Borate, which had an orange flames beginning with a green flash. It's metal was Sodium. Unknown #2 burned with a blue, green, and white flame with orange sparks. We identified Copper Chloride by its blue color before it was mixed with methanol and lit, and the presence of a white color indicates the presence of red as well as green and blue. Strontium Chloride was the only compound with a red flame, so that must have been the other component. It's metals were Copper and Strontium.
7. Do you think we can use the flame test to determine the identity of unknown in a
mixture? Why or why not?
Yes, it is possible, but not with the naked eye, since different elements may give off wavelengths that differ by a few nanometers. Scientists actually use satellites to determine the chemical composition of stars and planets based off of their emissions.
8. Why do different chemicals emit different colors of light?
Different elements have different numbers of differently shaped orbitals, and the electrons necessarily require different amounts of energy to make quantum jumps between these orbitals.
9. Why do you think the chemicals have to be heated in the flame first before the colored
light is emitted?
Heat is just transfer of energy; when heat is applied to the electrons, they are taking in energy, but only in the specific amounts required to make quantum jumps. They must re-emit that energy of photons of a specific wavelength.
10. Most salts contain a metal and a non-metal. Look at the compounds we tested and
explain how we can be sure that it is the metal atoms that are responsible for the colors
that you see.
There are many salts containing Chlorine and a metal (e.g. Sodium Chloride, Strontium Chloride, and Copper Chloride). One common color between mots of these is orange, found either in the color of the flame or in sparks, but most of them also have their own distinctive, prevailing colors, which leads to the conclusion that the metals show their colors more than the non-metals.
11. Colorful light emissions are applicable to everyday life. Where else have you observed
colorful light emissions? Are these light emission applications related? Explain.
Colorful light emissions are seen on LCD screens every day by many of us. These screens are comprised of red, green, and blue pixels, and these pixels light up in various combinations of the three colors to create the variety seen on your laptop. That's color theory at work! However, LCD pixels do not require elements to emit their specific photon wavelengths. They are simply florescent lights behind, among other things, a liquid crystal that will only let red, green, or blue light through it and will darken if electric current is run through it, so this is not very related to the experiment. More closely related are "neon" lights which are so common above stores and hotels (actually, they used to be more common than they are now). Neon is in quotations because, although this is the most famously used gas in these signs, Neon only burns red. To get another color of light, one needs to burn a different element.
12. Can you think of a way in which to use the flame test? Please describe below.
I can think of similar applications in the field of science. For example, scientists can discover the chemical composition of a planet's atmosphere, a star, or a nebula just by looking at a picture taken by a deep-space telescope and analyzing the emitted light. Because each element gives off its own wavelength, scientists can tell which unreachable 13,000-light-year-away planets could sustain life.
13. What professionals would use this type of information?
Firefighters might find the information from the Flame Test useful, as suggested by question 15, so that they can know exactly what they are dealing with. Forensic specialists might also find the information useful, potentially, so that they could identify certain elements in a crime scene clue. Geologists, paleontologists, or archeologists might find it useful for similar reasons. Finally, astronomers/astrophysicists would also find the information useful, because of the application described in the answer to question 12.
14. Why is the Statue of Liberty green?
The Statue of Liberty is green because it is made of copper, which is ordinarily metallic and golden-brown, but which oxidizes in air, becoming green. On contact with oxygen, copper's electron configuration will change, and the energy of the emitted photons will change accordingly, from golden-brown to green.
15. Suppose you were a firefighter and you were called to a chemical plant fire. Upon arriving,
you see a bright violet/purple flame. What chemical would you know is burning?
Methanol has an indigo flame, which is very close to violet. Any number of compounds might be mixed in to make a methanol-based flame change color from indigo to violet. Color theory tells us that all that's needed is a very small amount of red color.
16. Using the information in your data table, design a fire works display that transitions
between four different colors. Explain what is happening.
One might not only create a firework display using four different colors, but incorporate four different colors into one firework! It's easy. A firework has multiple "stars," which are comprised of a fuel, oxidizer, metal powder, binder, and element to add color. These stars are what you actually see in the sky; they're set alight when the firework detonates, and the color compounds in them burn. A firework can have as many or as few stars as one can fit inside the shell, and the only limit on shell size is what one can launch in a mortar tube. I could, for example, build a firework with 40 stars. I'll give them all fuel, oxidizer, and iron powder to add brightness when they burn. Then, I'll add Strontium Chloride to ten, Sodium Chloride to ten, Barium Chloride to ten, and Copper Chloride to ten. That will make ten red, ten yellow-orange, ten green, and ten turquoise when they burn.
17. Research some information about the origin of fireworks. Explain how they are made,
what chemicals are used, what colors they burn and their uses.
Black powder, the result of mixing charcoal, sulphur, and saltpeter, originated in China approximately 2,000 years ago. 1,000 years after that, the Chinese monk Li Tian invented the firecracker. After being brought to Europe by Marco Polo (by most accounts), black powder was used in guns, rockets, and cannons. Fireworks first appeared in Italy, but were quickly adopted by Germany. After a while, England became fascinated with the projectiles. ("History of Fireworks." Phantom Fireworks. N.p., n.d. Web. 27 Sept. 2014.) A firework shell is launched from a mortar, with a small bursting charge that will both propel the shell out of the tube and light its fuse. Once the fuse has burned down completely, a bursting charge inside will explode with two effects. The first effect is to propel several stars in all directions. The second effect is to light those same stars, creating extremely bright and colorful globes hurtling in all directions. Brain, Marshall. "How Fireworks Work." HowStuffWorks. HowStuffWorks.com, n.d. Web. 28 Sept. 2014. Many chemicals are used to add color to fireworks, including (in order from red to violet) Strontium, Lithium, Sodium, Barium, Copper, and Magnesium or Iron (white). "How Firework Colors Work." About. N.p., n.d. Web. 28 Sept. 2014.
18. Determine the wavelength of any two of the elements that you observed. Calculate the
frequencies (c=wavelength x frequency) and the energy (E = hf) for each. Make a table of
your results with the following columns: 1: wavelength in meters, 2: frequency in Hz, 3:
Energy in J. List the results in order form the lest energetic to the most energetic photons.
Element Wavelength (m) Frequency (Hz) Energy (J)
Strontium 6.5 x 10^-7 m 4.62 x 10^14 Hz 3.048 x 10^-19 J
Copper 4.75 x 10^-7 m 6.32 x 10^14 Hz 4.188 x 10^-19 J