The purpose of this lab was to use empirical evidence to determine the type of chemical change and be able to write these changes as balanced reactions. We found that 9 out of 16 reactions yielded precipitates and 1 had a color change (Cu(NO3)2 x KI). To set up this experiment, we combined different solutions in a well plate. 3 drops of Ca(NO3)2, Cu(NO3)2, Ni(NO3)2, and Zn(NO3)2 were put into wells A1 to A4, B1 to B4, C1 to C4, and D1 to D4 respectively. Next, 3 drops of KI, KOH, Na2C2O4, and Na2SO4 were placed in wells A1 through D1, A2-D2, A3-D3, and A4-D4 respectively. We then let the solutions sit awhile before recording our observations. In wells A2, A3, A4, B2, B3, C2, C3, D2, and D3, precipitates formed. Also, in well B1 had a color change but no precipitate. …show more content…
The reason why Na2SO4 only reacts with Ca(NO3)2 is because when sulfate combines with calcium (or Ag, Sr, Ba, Pb), it becomes insoluble. In the other reactions, copper, nickel, and zinc were all soluble when combined with sulfate. Also, no precipitate formed when mixed with KI because both elements in the molecule are soluble when combined with other elements, except for Ag, Pb, and Hg when combined with a halide. This lab shows that some elements and ions are soluble while others are not and that there are some exceptions to the rule. During our first try, my group had few errors. In our B4 well, a precipitation reaction occurred when in actuality, there should not have been
Two tests were done to solidify a conclusion. First, a random chemical was chosen out of the 5 unidentified chemicals provided. Afterwards, a hypothesis was created, based on the properties observed just by looking at it. The unknown substance (Unknown B) was thought to be Calcium Chloride as a result of both liquids being colorless. Next, you create two different chemical reactions to attempt to support your hypothesis. In this experiment, the chemical was tested to if a precipitate could be identified. To begin the experiment, 3 drops of unknown B were added into a clean plate well, then 3 drops of Sodium Carbonate were added in the same well. The second test was very similar to the first. Initially, you added three drops of Unknown B into a different plate well than test one. Subsequently, three drops of Sodium Hydroxide were added to the second well. Finally, you clean of the work space with a paper
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.
For each solution which formed a precipitate (Cl,CO32) the solution was centrifuged for 5 minutes and
The litmus test might have contributed to a significant loss of the precipitate, but only one instead of multiple tests were performed to see if the reaction mixture was acidic enough. Given the carefully controlled experiments and the 90% yield, it can be deemed that the methods used to perform the experiments are full proof and performed as immaculately as possible.
The four kinds of chemical reactions are synthesis, decomposition, single-displacement and double-displacement. Materials: Bunsen burner, sparker, tongs, 5 test tubes, scoop, wooden splint, lead(II)nitrate, magnesium wire, copper(II) carbonate, hydrochloric acid, zinc, potassium iodide, test tube tack, googles, apron, gloves and a metal test tube holder. Methods: Experiment 1: Synthesis 1, Obtain a piece of magnesium wire.
A summary of knowledge that must be known before the performance of this lab is as follows: a chemical change is a type of reaction where the original substance changes into another substance, also commonly known as the process of a chemical reaction. Every chemical reaction has an equation which can help determine what type of reaction it is. The five types of chemical reactions are synthesis reactions, decomposition reactions, single-replacement reactions, double-replacement reactions, and combustion reactions. A synthesis reaction is when two or more elements or compounds react to form a single compound, while a decomposition reaction occurs when one compound breaks into two or more substances. The general equation for both of these reactions, respectively, are A + Z → AZ and AZ
Precipitate can emerge in the form of a
The amount if precipitate in each reaction will be measured against the volume ratio, then, the empirical formula can be found. The expected formula is Cu3(PO4)2 when predicted using the charges of ions, which would be at a 1 :1 ratio. Methods: First, seven small test tubes that are labeled in a test tube rack were obtained. Next, with two puppets ready, one pipet was filled with 0.1 M cooper (II) chloride and the other with 0.1 M sodium phosphate. Then, the appropriate number of drops of both solutions were added into the labeled test tubes.
Looking at the way a substance combining with another substances that can make a whole different reaction is very interesting. The main goal of this experiment is to observe some typical chemical reactions, identify some of the products, as well as summarize the chemical changes in terms of balanced chemical equations. This chemical reactions lab will require an apparatus, chemicals, procedure, and lab questions to help the performer of the experiment understand and comprehend the lab being performed. The lab is a way to see how the combining the different substances will create a slow, unique, and abstract reaction or it will reveal a quick and fast reaction by the combining of the different chemical substances we will be using throughout the lab.
In part A, the solution was either to be composed of silver or lead and in part B, it was either composed of barium or calcium. In part C, a flame test was done to determine the identify of various cations through the color of each flame. The experiment was done on unknown solution 1 and since HCL is a strong acid, it was added to the unknown solution to break up the salt from the metal and make it soluble, it is primarily added to separate part A cations (PbCl2, AgCl) from part B cations (BaCl2, CaCl2). In part A, heat was used to separate lead ions in step 5 and presence of lead was confirmed after step 6.
Several of the chemicals were clear, including Sodium Hydroxide, Sodium Sulfate, Potassium Nitrate, Calcium Nitrate, Magnesium Nitrate, Sodium Chloride, and Sodium Phosphate. The other chemicals were all different colors, including blue and yellow. Potassium Ferricyanide was a dark yellow. Likewise, Iron (III) Nitrate was an orangey-yellow color. Lastly, Copper (II) Nitrate was a light blue. Throughout the lab, different reactions took place. Some products changed colors, formed precipitates, and one even produced gas. There was no reaction between Potassium Nitrate and any other reactants, including Potassium Ferricyanide, Sodium Phosphate, Sodium Sulfate, Sodium Hydroxide, Sodium Chloride, and Sodium Carbonate. These all remained clear, except for the Potassium Nitrate and Potassium Ferricyanide that has a natural yellow tint due to the color of the Potassium Ferricyanide. Magnesium Nitrate did not react with Potassium Ferricyanide, Sodium Phosphate, Sodium Sulfate, or Sodium Chloride. These all remained clear, and the Potassium Ferricyanide and Magnesium Nitrate remained a yellow tint. It did react with Sodium Hydroxide and Sodium Carbonate to form precipitates,
Sulfuric acid was added to the precipitant; in order, to form a salt, copper (II) sulfate (CuSO4) and water (H2O). Stirring sulfuric acid into the precipitant formed a clear light turquoise color solution, which makes this reaction be considered an exothermic reaction because the heat produced from the stirring which results in the formation of the salt and water from the acid and the base. The formula unit, total ionic, and net ionic equations of the acid base reaction can be seen in Equations 4.The final reaction to return copper back to its original form was an oxidation reduction reaction between copper (II) sulfate and aluminum. In this reaction, aluminum is oxidized while copper is
Our results showed that the equilibrium constant was greater than 1, showing that the reaction highly favors the production of products. As the volume of KSCN decreased, the absorbance decreased. The average keq for the complex ion formation of Fe and SCN was 1.48 x 105. Because our actual value was greater than 1, the reaction between Fe and SCN was one that favored the production of products. This is logical because throughout all of our trials, we ensured that the volume of KSCN and HNO3 were smaller than the volume of Fe(NO3)3.
The original color of each compound was recorded. After this, two more drops of the compounds were added to the individual wells so that each well would contain a unique combination of two compounds. Once this was completed, it was determined which solutions had reacted by whether or not a precipitate formed in the solution. If a precipitate had formed, the new color of the solution was recorded.
One discrepancy that has to be explained would be for Part F(Chemical Reactivity Of Some Representative Elements), question 3 is we failed to obtain a result because time ran out before we could complete the experiment. However, based on my research, the calcium hydroxide salt would be more soluble than the magnesium hydroxide salt because the calcium is more reactive than magnesium. This is because calcium has 20 electrons thus, an electronic configuration of 2.8.8.2. However, magnesium has 12 electrons thus, an electronic configuration of 2.8.2 . In other words, calcium has four electron shells but magnesium has three making it easier for calcium to lose an electron as the distance between the nucleus and the electrons in calcium is further