Scientific Explanation Lab Report

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

concentration was plotted in order to estimate the concentration of the unknown solution (Figure 3).

The purpose of this experiment is to determine an unknown concentration of acid (hydrochloric acid) with a standard solution of a base (sodium carbonate) using titration method.

3. If a student did not remove all of the bubbles from inside the buret before reading the initial volume and beginning the titration, will this cause the calculated concentration of the hydrochloric acid determined from that trial to be higher or lower than the actual concentration? Explain your answer in complete

Question: The equivalence points of the two titration curves were not in the same pH range. Explain. (Why was the pH at the equivalence point different for the two different acids?)

To improve the results from the experiment buffer solutions that were not whole pHs could have been used e.g. pH 4.5, 5.5 etc. This would have provided more reliable results as a wider range of results would have been produced. Using pHs with decimals would also help to more accurately determine the optimum pH as the optimum may have been above or below the pH stated in the hypothesis; 8. In this experiment however the optimum is taken at 8 because the graph does not rise again.

2. In Part I of this experiment, acetic acid is titrated with NaOH. The net ionic equation for acetic acid reacting with NaOH is CH3COOH+ NaOH =NaC2H3O2+H2O. The equivalence point is when the moles of the titrant and other solution are equal.. You detect the equivalence point by obtaining the point on the graph where the steep pH occurs. In titrating acetic acid with NaOH, the pH is greater than 7 at the equivalence point because NaOH is a strong base so it results in a higher pH, due to the OH- ions in the solution.

Explain the pH scale and how it is used to indicate acidic, alkaline, and neutral solutions.

ii. The second part of the titration series involves titration of NaOH with Hydrochloric acid (HCL). Again, three reps of titration and a blank titration have to be completed. A volumetric pipet is used to measure 10.00mL of HCL into three labeled conical flasks. Then the flasks are filled with deionized water until about the 50mL mark. A buret is

must be above 8.5 and below 6.5. If the pH is too acidic, then the

The first titration (with use of the PASCO program) is the most accurate titration that the lab group can perform. The titration curve gives many different variables, with accuracy that passes what humans can do without a machine. But the problem with this titration is that the curve or change to neutrality can often be sudden and out of nowhere. This means that it is very hard to just titrate a solution to become neutral, and often will change into the opposite property, essentially an acid to base and vice versa. The titration with use of an indicator is less accurate, but shows a more visual representation about how a titration takes place. The change in color is a less accurate indication of the volume it takes a solution to change to be neutral, but the visual change is helpful in a classroom laboratory setting. The preference is the first titration method, because it is more accurate and can give more reliable data, since the PASCO machine and drips added are not affected by human

During a titration the pH of the solution will be monitored using a pH meter from that we get a titration curve. The titration curve is then used to determine the equivalent molecular weight and Ka value of the unknown weak acid, from that we are

Using Graph 1: The Volume of Titrant Added in order to reach the Endpoint and the Corresponding pH Values, observe the vertical line of each titration and see the points in which the horizontal lines intersect it. These points give the

First, three titration curves and three second derivative curves were created to determine the average pH at the half-equivalence point from the acetic acid titrations. Titration curves were used as visuals to portray buffer capacity. The graphs and a table, Table 1, that showcased the values collected were created and included below. The flat region, the middle part, of Figures 1, 2 and 3, showed the zone at which the addition of a base or acid did not cause changes in pH. Once surpassed, the pH increased rapidly when a small amount of base, NaOH, was added to the buffer solution. Using the figures below and

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.