Essay about Qualitative Analysis Discussion

Pour 50 mL of distilled water into a 100 mL beaker, and then add the unknown substance into it. Mix thoroughly to create the aqueous solution. Now fill a new cuvette with this new solution and place into the SpectroVis Plus device; after wiping the outside with a Kimwipe as usual. Be sure to take note of the absorbance when wavelength is at its maximum. Afterwards, Be sure to take all solutions containing Iron(III) and pour them into the container specified for hazardous wastes. ​

b) Iron and Barium were present in unknown 3. Assigned unknown reacted with all 4 reactants and formed precipitate with 3 of them (Sodium carbonate, sodium hydroxide and Sulfuric acid). During the experiment it reacted very similarly to Iron (III) nitrate and Barium nitrate. For example, with it was tested against Ammonium Chloride, the color of the solution changed to a light green, very identically to Iron (III) nitrate and Ammonium Chloride. Besides, unknown 3 formed an orange brownish precipitate when it was tested with sodium carbonate. Iron (III) nitrate acted similarly. Moreover, unknown 3 reacted similar to Barium nitrate when it was tested against ammonium chloride and sulfuric acid. It did not form any precipitate with ammonium chloride but formed a very light white precipitate, which is identical to barium nitrate’s reaction against sulfuric acid. Therefore, the two present metal in unknown 3 are Iron and barium.

One of the most important skills to have in the chemistry lab is the understanding of how chemicals will react. Knowing for example, how a chemical will react with a metal, is an excellent way of determining the amount of a particular metal in a deposit. This knowledge was used in this lab to determine the amount of copper in an unknown sample mixture. It is also known that the determination of the percent concentration of a certain solution, will directly effect the percent transmission and absorption of a solution, dependent upon its dilution. By first testing known concentrations of a solution, and plotting this information graphically, a line is formed

These combinations were as follows: Iron (III) Nitrate and Sodium Phosphate Iron (III) Nitrate and Sodium

The problem that was trying to be solved in this study deals with analyzing unknown solutions. In this particular case, a chemical company has several unknown solutions and to correctly dispose of them they need to know their properties. To figure out the properties several qualitative tests were performed throughout the study (Cooper 2012).

In reference to the analysis of anions, Table 1 shows that a precipitate was formed when our unknown was combined with HNO3 and AgNO3, thus indicating the presence of a chloride ion. Because our unknown did not form a precipitate due to HCl and BaCl2, separate, effervesce, or smell, we concluded that neither sulfate, nitrate, carbonate nor

The Copper Chloride displayed and used to complete this lab had led us to the following observations;

the ions of SO42-, CO32-, Cl-, and I-,identify them separately, and use the observation to identify the unknown.

In well 3A there was a chemical reaction between the sodium phosphate and copper sulfate. There was a light blue precipitate formation which proves there was a chemical reaction.

In this task the concentration of an unknown sample of copper sulphate using colorimetry was used to find the concentration. In this investigation copper sulphate was used which is CuSO4.5H20 as a formula. To make a standard solution which was 1M, the same clean equipment was used to make up the standard solution as used to make sodium carbonate. However there was one difference and that was that the hot distilled water was used to dissolve the copper sulphate crystals. There had to be enough hot water in order to dissolve the crystals into the beaker and then add cold distilled water to cool the solution.

The black precipitate was allowed to settle and then the supernatant, the clear liquid that lies above a precipitate, was decanted, or poured carefully off. Then, 200 mL of hot distilled water was added and the precipitate was allowed to settle to repeat the decanting process again.

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

At the end of the experiment when the lid was removed, it was found out that the blue colour of the copper (II) sulphate solution has faded away. It was turned to pale grey and there were some precipitates present. It was the zinc powder that was in excess to ensure that the copper (II) sulphate solution could react fully with the zinc powder.

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

For generating valuable data with a desired accuracy and to quantify concentration of the constituents present in the samples being analyzed.