Chemical Oxygen Demand (COD)

This process of rising up, condensation, and revaporization eventually results in vapor comprising 100% of substance A. This process is then repeated at the boiling point of substance B. The efficiency of this process is reflected by the reflux ratio, which reveals how many condensate drops reenter the stillpot for every distillate drop

In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.

Given that 3.327 g of product was produced during the reaction, how many grams of water were released as water vapor? (moles = mass/molecular weight). From observation it appeared 1.673 grams of water were released as water vapor. 5. Write a balanced equation for the decomposition of copper carbonate hydroxide hydrate.

The active ingredients in the alka seltzer tablet are “As the tablets dissolve, the sodium bicarbonate splits apart to form sodium and bicarbonate ions. The bicarbonate ions react with hydrogen ions from the citric acid to form carbon dioxide gas (and water). This is how the bubbles are made.”(Scientific American) These bubbles are representative of a chemical change and the resulting carbon dioxide should increase the water 's density. This may actually increase the volume of the water taking longer to boil, this difference may be minuscule, even negligible, but there 's a possibility for distinct change in results. This scientific American puts it best “For the reaction to occur,

This chemical would be called calcium sulfate trihydrate. When finding the mass of this chemical, you find the mass of the calcium sulfate and then add 3 times the mass of water to it. (40.08 + 32.066 + 4(15.999) + 3(2(1.0079) + 15.999)) = 190.19 g/mol. The water can easily be removed from a hydrate just by heating strongly. You will be weighing a hydrate and heating it to remove the water (now called "anhydrous salt") and weigh it again.

This low percent recovery is because some of the solutions spilled onto the table, losing a lot of the precipitate. The recovered ethyl-4-aminobenzoate’s boiling point was within the accepted range of 85C; meaning, the amount recovered was pure. The % recovery for the benzoic acid was 5.33%. This low percent recovery could be due to the fact that instead of adding NaCl to increase the precipitate amount, the salting out effect, more of the HCl was used. This caused the precipitate amount to increase slightly but not as much as it could’ve if the salting out effect was used.

The purpose of this lab is to observe the reaction between hydrochloric acid and magnesium metal. When the substances are reacted over water, the products produced are a salt in aqueous solution and a gas. While the salt remains in the water as part of a solution, the gas produced will float to the top. Though water vapor pressure will affect the pressure of the gas in the eudiometer, it is possible to apply Dalton’s law of partial pursues to find the dry pressure of the gas. When the dry pressure is determined, the volume of the gas at STP can then be determined and what the experimental volume of one mole of the gas would be at STP.

The increase of temperature has 2 effects on almost all solutes that are solid. They dissolve more quickly, and a greater amount of the solution dissolves. The other way to change the solubility, is when the solution is a gas, is to change the pressure. At high pressure the gas solubility in a liquid solvent increases(1). However, for gases.

C is plotted and fitted to a logarithmic-line to illustrate the saturation effect, shown in Figure 1. Then using equation 12.8 in the lab manual, C/Y is calculated and plotted versus C and fitted to a straight line, shown in Figure 2. From the fitted line, Ymax, which is the maximum number of moles of acetic acid that can be adsorbed on the surface of the charcoal per gram of charcoal, can be calculated from the slope. Then, using Ymax and the value of the y-intercept, K, which is the ratio between the rate constant k1 of the forward reaction (adsorption on the charcoal) and the rate constant k-1 (detachment from the charcoal), can be determined. For calculations, refer to Appendix E. Finally, multiplying Ymax by Avagadro’s number will give the number of AA molecules adsorbed on the surface of one gram of charcoal at saturation.

According to Berger (2012, p.1), desalination battery is run by doing reverse cycles on the mixing entropy battery. The contains some materials that are capable of taking out the salt from seawater (Berger, 2012, p.1). According to Smith, as cited by Lavars (2016, p.1), the salt is diffused from the positive electrode to the negative electrode in the battery using a separator. A membrane is then put between the electrodes to prevent the sodium from entering, so it cannot be mixed with the water that has been desalinated. Figure 3 shows the structure of the sodium battery.