Properties of Hydrates

1. The first experiment is Preparation of a Cobalt Amine Bromide Product ; Synthesis #3 was used to create the compound. Added 5 grams of cobalt carbonate to 20 mL of hrdrobromic acid in a beaker. Noticied a slight color change to dark purple. Solution frothed after it settled I mixed in 15mL water and

In this experiment, it is very important to ensure that the deionized water is just basic and not acidic in order to obtain accurate results. Calcium oxalate does not precipitate in an acidic solution because of the formation of H2C2O4-, an ion that does not precipitate with Ca2+ . Allowing the precipitate to settle is also very

Beran, J. A. Laboratory Manual for Principles of General Chemistry. 9th ed. Hoboken, NJ: John Wiley; 2010

The purpose of this particular lab was to experiment and identify the chemical and physical changes throughout the experiment.

The purpose of this experiment was to determine the percent by mass in a hydrated salt, as well as to learn to handle laboratory apparatus without touching it. The hydrated salt, calcium carbonate, was heated with high temperature to release water molecules. Gravimetric analysis was used in this experiment to determine the percent by mass of water in a hydrated salt. The hypothesis of this experiment was accepted on the basis that the percent by mass of volatile water in the hydrated salt would be fewer than 30%. The percent by mass was determined by the mass of water loss devised by the mass of hydrated salt multiplied by total capacity

The Vitamin C turned to a red/orange color with no physical/chemical reaction. For the salt the solution turned to an orange color with no physical/chemical reaction. With the Alka-Seltzer, the solution turned to a brown color with no reaction as well. Last but not least, the Baking soda turned to an orange/brown color with no reaction.

between the unknown cation and chlorine (Cl - ) was also formed from the addition of HCl. HCl was

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

5. Was there any evidence that some of the copper (II) chloride was left in the beaker? Explain.

Solub. Or Reaction w/ hot H20: no change observed from the cool water and is soluble

When the red Co(NO3)2*6H2O crystal was added to the white NH4 crystal, and water was added to dissolve, the solution turned blue in color. As the solution was nixed, the color changed to that of a blue-purple and a blue precipitate formed. When the 6 M NH3 began to be added, the color shifted to dark purple color after 15 mL of ammonia and the amount of the precipitate was less. After 20 mL of ammonia, the solution became a red brown with very little of the blue precipitate. After 30 mL of ammonia, the solution was similar in color to an iodine solution, a dark brown-red, almost black in color. At this point there was no visible precipitate on the surface of the solution. After 40 mL of the ammonia had been added, the solution was the same iodine like color as before. When closely examined, there was a black precipitate that had settled on the bottom of the beaker. At this point, hydrogen peroxide, 3% H2O2, was added to solution. After 4 mL of the H2O2 was added, the solution was the same color and the precipitate had not changes. After 8 mL of the H2O2, there was not noticeable change. After 12 mL of the H2O2, the solution was slightly redder in color but the precipitate had not changed. After 15 mL of H2O2, the solution was the same color and no changes had occurred to the precipitate. At 17 mL, the solution began to effervesce slightly, though there

The white color implies that chlorine is within the mineral oil, thus did not react. Since chlorine did not react, it means that bromide isn’t a possible anion, leaving chlorine as the anion. In procedure 5, the unknown compound produced water on the watch glass indicating it could be a hydrate. The hydrate test was inconclusive because the number of waters of hydration shown in Table 5 was half way between being lithium chloride monohydrate and lithium chloride 2. The percent error, shown in Table 5, between the expected percent of water in lithium monohydrate and the accepted value, was high at 40% which meant that the unknown could not be properly identified as a hydrate. Repeating the hydrate test produced a similar percent which is shown in Table 7. The reason for these high percent errors is because lithium chloride and lithium monohydrate are both hygroscopic. In addition, Table 6 shows an increase in mass when unknown #42 was left outside, which suggest that the unknown compound is

B2.Place a few crystals of copper(II)sulfate pentahydrate in a test tube. Clamp the tube and heat in a horizontal position. One of the products is copper(II)sulfate. What is the other one? This decomposition reaction is easily reversible. Add a dropperful of water to the tube when it cools. Record what happens.

3. Leong, O. H. (2009). Qualitative Analysis. In Know Your 'O' Level Chemistry (pp. 101-103). Singapore: Panpac Education Pte Ltd.

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