The purpose of the lab was to understand and familiar with the laboratory environment and some fundamental operation such as measuring mass, volume; calculating density and separating solid from liquid by vacuum filtration. In the lab, we used sodium benzoate and react with Hydrochloric acid to form benzoic acid. There were two steps involved in the experiment, reaction and separation.
After the steps were completed, we measured the product and the percentage yield and compare the actual yield with the theoretic yield. C6H5COONa + HCI C6H5COOH+ H20 Procedure and Observation The procedure of the experiment is listed on the handout. In the experiment, we performed with microscale instead of a standard scale. At first. we obtained 0. 400gram of sodium benzoate to a 5ml vial. Next, we measured 3 ml of water into the vial and stir with a thin glass until the sodium benzoate dissolved.
Then we measured 1 ml of HCL and putted into vial slowly and dry it with vacuum filtration and measure the weight of the product. During the experiment, I saw the reactant change from colorless to milky cloudy solid and there were some odor released Data and esults Part A Mass of sodium benzoate 0. 402g Volume of water 3m’ volume Of 3M HC’ 0. 85ml Actual yield 1. 03g Theoretical yield 0. 3672g Calculation of Theoretical yield: N gram of sodium benzoate/144 gram per mole of sodium benzoate= 0. 5ml/1000 volume of HCl*3 Molarity of HCI Gram of sodium benzoate is 0. 3672 percentage Yield = 1. 03/0. 3672 x 100% = 280% t Of2 Solvent Volume(ml) Mass Density Absolute ethanol 0. 25 0. 228 0. 912 0. 5 0. 432 0. 864 0. 75 0. 635 0. 847 1. 0 0. 840 Discussion In the percentage yield is 280 % which is more than it supposed to be, which ignificantly more that theoretical value is. The cause of error are mainly due to drying of the product.
In the experiment, we used vacuum filtration and the power of the vacuum filtration is not strong enough and it does not take enough time to dry the product before measuring in the weight balance. Therefore, actual yield is more than theoretical yield. Conclusion Overall the experiment deems to be successful due to successful obtain benzoic acid from sodium benzoate. However, the only improvement is to take more time to do the filtration or use higher power of vacuum before measuring product.