Lab Report Sss's Law

Why Whales Lost Their Legs Kiara Rojas Honors Biology INTRODUCTION Millions of years ago, whales had legs. Pakicetus, the first whales, were land animals. Pakicetus does not resemble the whale at all from the outside but, they share a similar ear region that is unlike those of any other mammal. This discovery provided evidence that Pakicetus and whales are linked. The question is, why did whale lose their legs?

After the twenty minutes elapsed, the flask was cooled to room temperature and then titrated with the remaining NaOH until the colorless solution remained pink. The final volume was then recorded. While solution #1 was heating the same process was repeated with solution#2 and the second burette

The room temperature was measured throughout the lab and kept constant at 24°C (+/- 1°C), as the lab was conducted during the same time of

Procedure: My partner and I measured the temperature of NaCIO (bleach) and Na2S2O3 to prevent any misleading data. We then measured 250mL of each solution and poured 5.0mL of NaCIO and 45.0mL of Na2S2O3 in a styrofoam cup. As my partner measured the solution for the other trials, I stirred the mixture while checking the temperature until it reached its optimal level. After each trial, we recorded the temperature on our data table. We repeated the process until

Procedure: This lab starts off by making sure the logger pro and temperature probe are in proper condition. Then, the data collection must be adjusted to 15 minutes and 12 samples/ min. After that a Bunsen burner must be set up by assembling a ring-stand, ring, and wire gauze, and a crack-less beaker is used to boil some water. First the beaker and the large watch glass need to be weighed and the mass has to be recorded using a triple beam balance. Next, the beaker with 200g of ice is placed on the ring stand, and immediately heated over medium flame. An important note is to make sure the flame is perfectly adjusted so the ice does not melt on the counter while trying to adjust the flame. Furthermore, place the temperature probe in the ice so it is not resting at the bottom of the beaker, it is best to secure it with a small clamp. Additionally, click the green start button on the computer and stir continuously with a glass rod until the ice is completely melted. Once the ice has melted which is somewhere between 3-5 minutes, the stirring rate will slow

50mL of 2M NaOH was added to the two stacked Styrofoam cups in a 400mL beaker. The cup was then covered with a plastic lid and a temperature probe was inserted through the lid and into cup in a way so that it did not touch the bottom. 3-4 temperature readings were then collected by clicking “collect” on LabQuest to start Run 2, and initial temperature was determined. 50mL of 2M NH4Cl was then added to the NaOH solution in the cup and swirled around. The rest was repeated from the first

The purpose of these experiments was to familiarize one’s self with laboratory equipment as well as becoming competent with different types of units as well as different methods of measurements.

The independent variable for this experiment is the temperature of the water bath, as this is what factor is changing throughout the practical. The temperatures will be ranging from 10°C to 50°C in ten degree increments. This will allow for the effect of temperature on the rate of reaction to be

With the other two trials were 0.18g, for the second trial and 0.17g for the third trail for Mass of Sodium Acetate After 3 ½ Minutes (g). These results demonstrated that the first trial had the most sodium acetate in it and it had more time to react with the oxygen in the air. Errors were involved with the first beaker being weighed. The beaker needed to cool down for more than 1 min ensuring that the plastic balance was no get damaged. In a 30 second of planning out a new time limit which was 3 and a half minutes.

3 mL of a 1:1 isopropyl acetate and toluene mixture along with a spin vane was added to a 5 mL conical vial using a calibrated Pasteur pipette. A Hickman still and heating block was assembled. The connector and lower portion of the Hickman still was wrapped with aluminum foil and the top of the still was loosely covered with foil. The thermometer was placed into the heating block and was moved into the Hickman still once the temperature of the heating block was near the listed temperature from the lab manual. The solution was stirred slowly while the hot plate was turned on.

Next are the methods that where done in this experiment. The materials used where: A digital Thermometer, human

2 I poured 5.0 ml of NaCIO into a Styrofoam cup and then added 45.0 ml of the second solution. I stirred and recorded the highest temperature. Then poured the solution out, rinsed the cup and thermometer, and repeated the process using a different ratio of the two substances, keeping the total volume at 50.0 ml. I continued this process for other various ratios, recording the highest temperature of the mixture.

Step 11: Once the temperature has been identified prepare 2 beakers with 40 mL of water and heat up to the ideal temperature. Step 12: Repeat same process over

In experiment 10, the class was asked to demonstrate the basics of gas laws in order to understand the peeled egg Erlenmeyer flask demonstration. This experiment helps demonstrate Boyle’s Law and Amontons’ law for the class to gain an understanding of related gas laws for our thermodynamic knowledge.

This experiment was performed to determine the heat of neutralization between Hydrogen chloride (HCl) and Sodium hydroxide (NaOH). A temperature probe was used to measure the temperature of the reaction when the base (NaOH) was poured into the acid (HCl). The data was collected on logged on LoggerPro.