Experiment 1Measurement & Laboratory Tools:Diet versus Regular Soda'sIntroduction:The Scientific Method: All living and nonliving entities, from single cells and complex animals to stars andgalaxies, undergo change. They emerge, age, die, and continue to change even after death.Science is the careful inquiry into the many changes that occur within us, around us, andthroughout our universe. Some of the observations that we make about the properties and behavior of the matteraround us are qualitative and others are quantitative. The result of an accurate observation isa fact. Often we find patterns in the facts we observe. A law is a concise verbal ormathematical statement of a generally observed pattern of behavior. After many facts have been observed, it is human nature to try to discover or develop anexplanation for the observations (facts). Scientists use their imaginations and reasoningpowers to develop speculative explanations called hypotheses for their observations. Theythen perform additional experiments, make further observations to weed out false conjecture,and try to develop better explanations called theories. This approach used by scientists todevelop, test, and refine explanations for observed changes is called the scientific method. The use of the scientific method is not confined to scientific laboratories. Good detectivesuse the scientific method in investigating a crime, and doctors use it in diagnosing illnesses.The following is an example of the use of the scientific method in a hospital. A two-year-old child was brought to the hospital. The child had been vomiting for severalweeks. No apparent abnormalities were visible. Blood tests showed low hemoglobin levels.The red blood cell count was also low. These tests indicated anemia of unspecified origin.X-rays showed some opaque material in the intestinal lining and along the growth areas of thebones. With this information the doctors were ready to advance a hypothesis: that the opaquematerial accumulated in the intestines and in the growth areas of the bones was a heavy metaland that the child was suffering from heavy metal poisoning. It was now necessary to test the hypothesis. If there was a heavy metal, the child mustsomehow have ingested it. In this case, the first test consisted of asking the parents. Thedoctors learned that the family lived in a rundown house that had peeling paint and that thechild had a habit of chewing on windowsills. Since house paint can contain significantamounts of lead, a heavy metal, this lent support to the hypothesis, but it still needed furthertesting. The next test was for lead in the blood, and it was found that almost two and a halftimes the normal lead concentration was present. The hypothesis could now be regarded as confirmed. As a final test, treatment for leadpoisoning was provided. Calcium EDTA, a chemical that extracts heavy metals, binds themtightly, and carries them through the kidney membranes into the urine, was administered. Oneday after the injection a 25-fold increase in lead concentration was found in the child’s urine.A few days later the poisoning symptoms disappeared, and after a week the patient wasdischarged, cured.Bettelheim/March: Introduction to General, Organic, and Biochemistry, 5/e, p. 10 Whitten/Davis/Peck: General Chemistry with Qualitative Analysis, 5/e, p. 5Using the Scientific Method .... A Goal of this Experiment. Today's laboratory while not as dramatic as the aforementioned lead poisoning case, willinvoke your reasoning powers and some of the methods mentioned in this article. When youarrive in the laboratory take a look at the nutritional labels on the bottles of diet and regularsoda. What do you notice? What differences do you see in the quantities of the the primaryingredients? As you note the ingredients it becomes apparent that there are a number of ingredients in acan of soda. The primary ingredient is however water and soda is a classic example of asolution. A solution is simply a homogenous mixture of two or more substances. Wegenerally categorize the components of a solution. The ingredient that is there in the greatestquantity is referred to as the Solvent which in the case of our sodas is water. The otheringredients are referred to as Solutes. The word homogenous is important with respect tosolutions. It simply means that random samples of the solution have identical compositions. We will meet this important idea again in experiment three. For the moment though, the nexttime you put milk or creamer in your coffee or tea, ponder if this mixture would ever meetthe criteria of being a solution? Your TA will point out to you the location of two other containers. The labels on thesecontainers have been lost. All that we now about them is that one contains regular soda andthe other diet soda. You are going to have to determine which container contains what by theend of this laboratory period, by making some measurement that will allow you todifferentiate between the two. Taste is not a quantitative measurement!, and the soda in thecontainers have been thoroughly degassed (the soda is flat)! While you let your brain wrestle with this problem lets us introduce the various toolsavailable in this laboratory.Measurements: Mass, Volume, Temperature.Mass: Electronic Balances: In determine mass you have three models of electronic balances available to you. Thesebalances measure to 0.001g (1mg) and when you use them you should always record all threedecimal places. The S.I. unit for mass is the kilogram (1 kg = 1000g). However it is notcommon to express mass in the laboratory in kilograms.Be aware that these balances are somewhat delicate and very sensitive. Do not remove theplastic guard around each. While it may not always be practical to do so, it is good practice tostick with the same balance during any particular experiment. Pictured are the three modelsof analytical balances that we use in the General Chemistry. During the first lab, your TA willdemonstrate the various idiosyncrasies of each! When doing any weighing, please observe thefollowing: Do not remove the plastic guard around each balance.1.Do not move the balance, this throws off the calibration and necessitates recalibrationof the balance. 2.Weigh chemicals in containers that are dry on the outside. Never weigh directly on thepan.3.Weigh everything at room temperature.4.Zero the balance and keep the draft