Hydrochlorimetry Lab

The purpose of this report is determine if sodium chloride is a viable option as a deicer on winter roads. To determine this, one must compare a multitude of factors. In this lab, the freezing point depression of water, enthalpy of dissolution, cost, and environmental impact will be discussed. A large factor in how effective a substance is as a deicer is it’s ability to decrease the freezing point of water. If the freezing point of water can be lowered, the outside temperature must be much colder to reach this new freezing point, resulting in less ice on the roads.

The lab started off by measuring critical materials for the lab: the mass of an an empty 100 mL beaker, mass of beaker and copper chloride together(52.30 g), and the mass of three iron nails(2.73 g). The goal of this experiment is to determine the number of moles of copper and iron that would be produced in the reaction of iron and copper(II) chloride, the ratio of moles of iron to moles of copper, and the percent yield of copper produced. 2.00 grams of copper(II) chloride was added in the beaker to mix with 15 mL of distilled water. Then, three dry nails are placed in the copper(II) chloride solution for approximately 25 minutes. The three nails have to be scraped clean by sandpaper to make the surface of the nail shiny; if the nails are not clean, then some unknown substances might accidentally mix into the reaction and cause variations of the result.

In the second portion of this experiment we will keep the temperature constant and divide the ½ tablet of Alka- Seltzer into 2 pieces ,3 pieces and an unbroken ½ tablet. It is my belief that Alka-Seltzer

Carbonates and hydroxides produced a high pH in solution which suggests these are strong

Therefore, in order to balance acid rain a base would need to be added. Alka-seltzer tablets are considered a base, meaning that the two substances should cancel out and a create a normal pH level of 7. This, in turn should protect the soil from the harmful acts of acid

Science 1. Free ears in dogs are controlled by dominant allele (F), and attached ears are controlled by the recessive allele (f). In addition, Short dogs is due to a dominant allele(S), and long hair is due to a recessive allele (s). Which of the following is the genotype of the dogs with free ears and short hair? a. ffss b. FfSs c. ffSs d. Ffss 2.

Researchers at the University of California, San Diego discovered that stingrays have the same enzymes used by “boneworms” to break down whale carcasses, and help promote photosynthesis in coral. However, this enzyme in stingrays is used to regulate their blood pH. This discovery is leading scientists to get a better understanding of enzyme’s function in human kidneys to regulate blood and urine function. To examine the enzyme more closely graduate student Jinae Roa isolated cells from stingray gills and exposed them to different pH conditions. Her and Martin Tresguerres discovered the more elevated and more alkaline, the proton pump activated by pushing the cells inner cytoplasm to the outer membrane, therefore, relieving it of excess acid.

3. Upon adding 20 drops of NaOH, a white precipitate was formed signifying acidic impurity. In the second NaOH mixture, about 20 drops were administered and no precipitate formed indicating that the ample is more pure than before. Data: Weight of flask = 75.10 grams Weight of the flask with solids =

In acidic aqueous solution, a buffer is formed by the dissociation of the acid: HA ⇄ H+ + A- Hence, when acid is added, the excess H+ reacts with the A- to form more HA, lowering the pH and minimising the effect of the addition of acid. When alkali is added, the OH- reacts with the dissociated H+ to form water, which reduces the effect of the alkali by restoring the pH to normal levels. Alka Seltzer acts as a buffer because the citrate ions in solution (C6H5O73-) are able to react with H+ when acid is added, to form citric acid, C6H8O7. This neutralises the acid, increasing the pH. The excess HCO3- ions also react with H+ to form CO2 and water, hence lowering the pH and reducing the acidity of the solution. The HCO3- ions also act as a buffer when alkali is added, because they react with OH- to create water and CO32- ions, increasing the pH and reducing the effect of the addiction of alkali.

Jaspreet Singh Professor Paratore Biology 1 November 1, 2014 Spectrophotometry Identifying Solutes and Determining Their Concentration Statement of the Exercise or of the Problem The purpose of the lab experiment was to attain the following objectives: • Learning to Operate the Spectrophotometer • Construct absorption spectra for cobalt chloride and chlorophyll. Hypothesis If greater and higher concentrations of cobalt chloride are added to each solution then greater amounts of light would be absorbed by each solution. Thus a liner relationship will result in which the absorbance of a substance would be proportional to its concentration, which will be depicted, in a linear graph.

The next test used the test tubes labelled “cold” and , one again using a piece of liver and five milliliters of hydrogen peroxide with both being placed in the ice bath, both held vertical with a test tube clamp. After five minutes were up using a timer, the two tests were conducted. The test involving the boiling water had five milliliters of hydrogen peroxide poured into it. Meanwhile, the five milliliters of hydrogen peroxide was poured into the test tube labelled “cold”. After both tests, explanations were made about the

CLAIRE MUNTING 29/01/2018 Criterion C EFFECTS OF SURFACE AREA OF CALCIUM CARBONATE UPON RATE OF REACTION Calcium Carbonate Chips 1 Introduction: Within the current investigation, the effects of the surface area of Calcium Carbonate (CaCO3) in combination with Hydrochloric acid (HCl) upon its rate of reaction. CaCO3, commonly referred to as limestone, is an organic substance and is, in a sense, the crystallised “carbonic salt” of the element, calcium2. In addition to being a salt, the pH level of Calcium Carbonate is 9.91, and it is therefore, a basic substance, due to the fact that it is comprised of a pH level higher than 7, which is neutral3. HCl, however, is the bodily acid found in the stomach of human beings.

 Two of the same types of plants were used, in order for the results to be reliable.  One of the plants was labelled DISTILLED whereas the other was ACIDIC, so the results don’t get mixed.  The DISTILLED plant was used as a controlled variable, where normal spring water was used (pH 7.3)  The ACIDIC plant was the one the experiment had taken place on, this was where lemon water was used (pH 2.0)  Throughout the experiment pictures were taken, so one will be able to notice the colour change on the acidic plants, as it had started to slowly die. With both plants you are able to notice that they had both started to grow flowers, but more the spring watered plant than that on the lemon juice watered one.  The results of the plant growth was recorded to we would be able to notice the amount it had grown, this would be the water compared to lemon juice.

Introduction Buffer is a solution that resists a change in pH when bases or acid are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven. Buffer usually consist of a weak acid, and its conjugate base or a weak base and its conjugate acid. The function of buffer is to resist the changes in hydrogen ion concentration as a result of internal and environmental factor. This buffer experiment is important so that we relies the important of buffer in our life.

Introduction The goal of the experiment is to examine how the rate of reaction between Hydrochloric acid and Sodium thiosulphate is affected by altering the concentrations. The concentration of Sodium thiosulfate will be altered by adding deionised water and decreasing the amount of Sodium thiosulphate. Once the Sodium thiosulphate has been tested several times. The effect of concentration on the rate of reaction can be examined in this experiment.