Flame Test Lab Report Essay

Based the data collected, the identity of the unknown #42 is lithium chloride. Because the unknown compound produced a bright red pinkish flame, shown in Table 1, the possible cations based on the CRC Handbook were lithium or strontium 1.The known 1M lithium chloride also produced the same colored flame as the unknown, suggesting that the unknown compound has lithium. Since lithium produces no precipitate with the compounds in Table 2 and strontium produces a precipitate with the same compounds, the observations in Table 2 indicate that the unknown’s cation is lithium 4. Using the solubility table, process of elimination, and the results in Table 3 the possible anions for the unknown compound were chloride and bromide4. The production of precipitate

For example, silver nitrate formed a white precipitate when it was tested with ammonium chloride. In contrast, unknown 3 did not formed any precipitate with ammonium chloride. Ammonium chloride change the color of unknown 3 to a light green while the solution of silver nitrate and ammonium chloride was cloudy white solution. Likewise, the metal in unknown 3 could have been Calcium neither. Data and observation shows that calcium nitrate whether formed a white precipitate or did not react at all while unknown 3 formed an orange precipitate. Therefore, silver and calcium are not the two metal present in unknown

We repeated this for a total of 6 known substances and 3 unknown substances. We also made a table for each element showing the color of the flame that we saw,

5. NaCl, sodium chloride, is a common salt and it burns in the flame test.

Many signs show that a chemical reaction has occurred. Some ways we know there is a chemical reaction are the formation of gas, formation of precipitate, change in temperature, and,or change in color. In part one of the experiment, we know there was a chemical change because of the formation of the white precipitate. We poured the ammonia and water in the flask with alum and water, forming a white, cloudy substance in between the two liquids. The white, cloudy substance between the two is liquids is also known as aluminum hydroxide. The second part of the experiment was very similar to the first, but in the second part we mixed epon salt, water, and ammonia. The precipitate formed from mixing the epson salt, water, and ammonia was called magnesium hydroxide.

The objective of the experiment was to observe different reactions with different chemicals. The experiments emphasized on the chemical changes occurring in acids and bases as well as color changes and bubble formations. The experiments allowed for a better understanding of the undergoing chemical changes in mixtures. Some mixtures instantly changed colors while others were transparent or foggy. Some mixtures produced thick color that created solids called precipitates. Mixtures KI + Pb(NO3)2 and NaOH + AgNO3 both produce noticeable precipitates after a while. It was interesting to see the different acidic and base reactions like the fuchsia color formation in NaOH + phenolphthalein.

Fireworks get there colour form metal compounds contained inside. Different metal compounds give different colours. Sodium compounds give yellow and orange, for example, copper and barium salts give green or blue, and calcium or strontium make red. Different metal salts give different colours in fireworks displays.

Prior to conducting this lab, it was known that flame colors are produced from the electronic transitions in the metallic ions present in the salt compounds. When heated, the electrons absorb energy, jumping from ground states of lower energy to higher-energy, excited states. The electrons must return to their lower energy levels as energy is emitted in specific amounts in the form of light. Each energy emission correlates to a certain color, and since the transitions of metallic ions vary from each other, each ion produces a unique pattern of spectral lines, therefore creating an equally unique flame color.

Every element has its own specific line spectrum, each one is different. This is a method that scientists use to identify an element. “Because each element has an exactly defined line emission spectrum, scientists are able to identify them by the color they produce. For example, copper produces a blue flame, lithium and strontium a red flame, calcium an orange flame, sodium a yellow flame, and barium a green flame” (Douma). In a line spectrum test, the bands of color seen is the line emission.

In this experiment, I saw that the product of Tin (ll) Chloride mixed with Potassium Dichromate is different from the product that resulted from Tin (lV) Chloride when mixed with the same reactant that was used with Tin (II) Chloride, Potassium Dichromate. They both resulted with different colours and smell. Tin (II) Chloride resulted with a light green colour, whereas Tin (IV) Chloride resulted with bright yellow colour. Similarly, Iron (llI) Chloride had a different product when mixed with Sodium Hydroxide, Ammonium Chloride added with Aqueous Ammonia, and Potassium Ferrocyanide compared to the product of Iron (ll) Sulfate, when mixed with the same reactants that was used to react with Iron (III) Chloride. And also same for Copper (ll) Thiocyanate

Light is made up of different wavelengths (visible light is made up of the rainbow). If a substance could absorb specific wavelengths of light, then each substance will have a unique ‘fingerprint’. This could be proven by forcing light through a substance and seeing the different wavelengths of light that were displayed on the other side. If there are dark lines, that means that wavelength was missing and was absorbed. A second way to prove this would be to test if that same substance would release the wavelength it absorbed. In the candle experiment, the salt should give off a wavelength because of the intensity of the flame. If it is the same as the sodium street lamp, then that proves sodium will absorb and emit a specific wavelength consistently.

The cations in both the known and unknown samples were identified by using qualitative analysis, of which were determined to be acidic, basic, or neutral by using litmus paper. Acid-base reactions, oxidation-reduction reactions, and the formation of complex ions are often used in a systematic way for either separating ions or for determining the presence of specific ions. When white precipitate formed after adding hydroxide, aluminum ion was determined to be present in the solution. However, nickel was determined to test positive when the solution changed to a hot pink color after adding a few drops of dimethylglyoxime reagent and iron was present when the solution was a reddish brown color when sodium hydroxide was added to the mixture at the very beginning of the experiment. Qualitative analysis determines that ions will undergo specific chemical reactions with certain reagents to yield observable products to detect the presence of specific ions in an aqueous solution where precipitation reactions play a major role. The qualitative analysis of ions in a mixture must add reagents that exploit the more general properties of ions to separate major groups of ions, separate major groups into subgroups with reactions that will distinguish less general properties, and add reagents that will specifically confirm the presence of individual

addition, it can be seen that the emissions intensity of the luminous flame becomes darker as the dissolved pressure increases. The Luminescence of the luminous flame is generated by carbon particles receiving heat from the flame surface, so it is deeply related to the generation of PM [5]. Therefore, it is conceivable that the effect of effervescence of CO2 gas greatly affects the amount of PM generated.

In this project we examined three explanations that talk about (a) candle(s) in a jar and their investigation reasoning to why the labs they did were concluding in such a way. The first explanation resulted that the candle inside the jar took up all the oxygen molecules inside the flask which then lowers the pressure inside and the higher pressure outside the flask is what causes the water to rise up. The second explanation resulted in that the air pressure increases inside the jar because of the heat from the candle, which causes air to come out of the jar and once the candle cools down the pressure decreases and the pressure outside the jar increases which results in pushing the air in and making the water rise up. The third explanation resulted in oxygen inside the flask becoming carbon dioxide which then dissolves in water causing the air pressure to decrease under the glass and the higher pressure outside the flask pushed the water up the flask. I believe that explanation number three is right because the flame causes carbon dioxide to be created and that

The main objective of this experiment is to carry out qualitative analysis to identify metal cations in unknown solution 1.