Evaluation Of A Lab Experiment

We know that that the end point of the titration is reached when, after drop after careful drop of NaOH, the solution in the flask retains its pale pink color while swirling for about 30

Procedure: Using distilled water, premeasured containers and objects determine displacement of fluids and density of objects. Use ice and heat measure temperatures in Celsius, Fahrenheit and Kelvin.

The number of electrons forming a charge cloud around the nucleus is (pick one of the following) greater than; equal to; smaller than the number of protons in the nucleus of the atom.

groups. It was conducted to further the research in choice overload and paralysis of the mind.

Students will carefully observe acts of aggression and prosocial behavior on television, report their observations, and analyze their data to draw conclusions.

C. An unknown, rectangular substance measures 3.6 cm high, 4.21 cm long, and 1.17 cm wide.

To begin, three sets ofabout 0.3000g of KHP are weighed out on an analytical balance. Put the three sets of KHP into three separate, labeled flasks. All three sets of the KHP is then dissolved with approximately 50mL of deionized water. Next, a buret is used to start the actual titration. Buret is initially filled to 0.00mL mark with the NaOH solution, this is recorded as initial volume. Next, add 2-3 drops of phenolphthalein indicator into each of the three flasks containing KHP. A magnetic stir bar is then added to the first flask, and placed above a stir plate. Everything is positioned under the buret. Stirrer is put on medium speed and the titration can start. Slowly release the NaOH into the KHP flask. As the end point is reached, a pink color will be seen in the flask. When the lightest pink possible remains in the solution for more than 30 seconds titration is complete. The final volume is recorded, and the same steps are taken for the other two sets of KHP solution. Finally, blank titration is completed to determine deviation.

By using acid-base titration, we determined the suitability of phenolphthalein and methyl red as acid base indicators. We found that the equivalence point of the titration of hydrochloric acid with sodium hydroxide was not within the ph range of phenolphthalein's color range. The titration of acetic acid with sodium hydroxide resulted in an equivalence point out of the range of methyl red. And the titration of ammonia with hydrochloric acid had an equivalence point that was also out of the range of phenolphthalein.. The methyl red indicator and the phenolphthalein indicator were unsuitable because their pH ranges for their color changes did not cover the equivalence points of the trials in which they were used. However, the

Alford(2015) reported the psychological effect of spending a substantial period of time looking into a pair of eyes. These effects were researched by Giovanni Caputo in a series of experiments involving test subjects looking into their own eyes via a mirror and a second study in which the participants where given partners and asked to stare into each others eyes. Alford claims that these experiments provide enough evidence to conclude that you can change your psychological state by looking into a pair of eyes for 10 minutes or longer.

The last week of with the lab assignment I see this tool can really save some time in completing job but can easily destroy them if you’re not careful. Also, when it comes to work to precision work like honing and polishing a trigger and sear. Hand files and honing stones should always be used. My first concern was the safety portion of the job. You’re talking about a tool that move at high and low speeds, so I would defiantly wear eye protection. Have a good grip of the tool and to keep your free hand a safe distance away from the rotating bit. I would also be sure do not wear loose clothing or jewelry that can become entangled with the rotary tool. A dust mask is also recommended. At 28,000 rpm, the rotary tool will create a lot of dust.

It is particularly important with this lab to be sure that the titration is carried out very carefully to avoid

number in order from 1 to 100, the make of the car, the price when new

Throughout the experiment, it was made evident that the benzoyl peroxide had the largest overall and average inhibited growth. This treatment is very commonly sold and purchased in a ten percent mixture while the others are typically used in larger percentages. The highest ring of inhibited growth for benzoyl peroxide was in trial two with 1.8 centimeters. The salicylic acid had its largest ring during the first trial, and it was 1.5 centimeters. Finally, tea tree oil also had its largest ring during trial one with a diameter of 1.2 centimeters.

The overall purpose of the lab is to have the students practice designing an experiment, gathering data, and then analyzing that data to form a conclusion using the scientific method. It also served to understand key terms such as hypothesis, dependent variable, and independent variable. The specific objective of this lab is to determine whether certain human body parts experience allometric or isometric growth. Allometric growth defines when certain parts of an organism grow at unequal rates in comparison to its whole, while isometric growth is when all parts of an organism grow at the same rate in comparison to the entire organism. The specific purpose of the lab is to determine whether or not specific human body parts experience allometric or isometric growth by comparing the ratios of height to two specific body parts, in the students’ case the right hand length and head circumference, in students and newborns. The students formulated the tentative answer that if a team of four compared their height to right hand length ratio, as well as, their height to head circumference ratio, to those of a newborn’s, then the students will discover that the right hand and head experience allometric growth in humans.

In this lab a acid-base indicator phenolphthalein was used to determine endpoint of a reaction HCl(aq) and KOH(aq). At the end point all of the HCl(aq) would have reacted with KOH(aq), and the pH becomes 7. The phenolphthalein would changed colours from colourless to pink indication when enough KOH(aq) was added. The purpose of numerous trials was to use the average volume of the 3 trials with similar measurements.