This experiment seeks to explore different chemical reactions conducted in the lab. A cation is defined as positively charged ions, which are K+ and Pb2+ in this experiment, and an anion is termed as negatively charged ions, which are CrO4 2- and NO3 2-. The major objective of this lab experiment was to examine the reaction between cations and anions, as well as observing, and documenting the chemical reactions.
We will be demonstrating the reaction between a solution of Lead Nitrate with a chemical formula of PbNO3 2, and a Potassium Chromate solution with a chemical formula of K2CrO4. The end result from mixing the two solutions should have a combined set of either the Pb2+ or K+ cation and likewise with the NO3 2- or CrO4 2- anion in its chemical formula. This experiment will demonstrate the chemical reaction between the cations and anions with an expected end result of a solid substance, which validates that a chemical reaction occurred. Procedure:
The following procedures and materials listed are what you will need in order to conduct the experiments end lab results. Equipment needed to perform this experiment is a 50 ml test tube, 100 ml beaker, 250 mL Erlenmeyer flask, Buchner funnel, and a Scale. The solutions needed are Potassium chromate K2CrO4 and a solution of Lead nitrate Pb NO3 2. Now to begin you need to access the cation and anion reactions iLab. Then click on the icon that indicates ‘Add Chemicals’, scroll and select the 1M Potassium Chromate and change the volume to 50mL then add the Potassium Chromate to a 100mL beaker.
Now you will need to use the existing beaker to add the 1M Lead Nitrate by selecting the same ‘Add Chemicals’ icon and scroll to the 1M Lead Nitrate and change the volume to 50mL. After adding the two solutions together the results in the 100 ml beaker will show a precipitate formation that settles to the bottom of the beaker, which indicates a chemical reaction between the two solutions occurred. Now you need to filter and transfer the precipitate by clicking on the toolbar and scrolling to the 250ml Erlenmeyer flask and the Buchner funnel which is located with all the previously used icons.
Then click on the 100ml beaker and move it to the Erlenmeyer flask with the Buchner funnel and select the pouring icon but make sure that the flask is correctly over the beaker otherwise the solution will not pour. Now you will need to weigh the remaining precipitate by selecting the Erlenmeyer flask and clicking on add solid to the 50ml test tube. Lastly, you will click on the scale that’s located with the other icons and weigh the remaining precipitate in the 50ml test tube. Observations and Results:
Based on the precipitate appearance in relation to my personal observations is that once the solutions of the 50ml Potassium chromate solution was mixed with the 50ml Lead nitrate solution was that the precipitate presented a solid, yellow, dotted substance. After I filtered and transferred the remaining substance containing the yellow precipitate into the 50ml test tube, I used the scale in order to determine the weight, which resulted with a weight of 16.160 g. The results were clearly that mixing the two soluble solutions together created a chemical reaction and formed a yellow precipitate. This indicates that one of cations and one of the anions produce a compound that is not soluble in water since it left behind a solid substance. Discussion:
It was evident that the yellow precipitate that I observed indicated a chemical reaction between Potassium Chromate and Lead Nitrate. We know that the cation is either K+ or Pb2+ and the anions are either CrO4 2- or NO3 2- because cations are positive and anions are negative. In Chem lab it told us that the precipitate was PbCrO4, which now we know that the Potassium and the Nitrate are soluble in water since the remaining substance formed a solid substance of PbCrO4, which was not soluble in water.
The resulting precipitate contains the combination of the cation Pb2+ and also the anion of CrO4 2- with the end products or results being Pb2 + CrO4 2- = PbCrO4, also known as Lead Chromate. Chem Lab also gave us the final equation of PbNo3 2 + K2CrO4–> 2 KNO3 + PbCrO4 showing that Lead Nitrate + Potassium Chromate reactants resulted with Potassium Nitrate + Lead Chromate which are called the products in this equation. This proves that the soluble solutions of Potassium Chromate and Lead Nitrate once mixed formed the insoluble Lead Chromate because of the solid substance or yellow precipitate that was left behind. Conclusion:
The cation and anion reaction iLab was not only fascinating but also very educating to conduct. This lab experiment was informing on examining the cations and anions chemical reactions although more research and experiments are essential to learning on mixing of two solutions and having an understanding of the reaction that took place. However, based on conducting this experiment the outcomes of having two soluble solutions of K2CrO4 and PbNO3 2 are likely to mix, react, and form a precipitate of PbCrO4, that indicates which cations and anions are soluble and insoluble in water.
