Rinsing process:
(1) Volumetric pipette and burette:
First rinsing with distilled water is to make sure the pipette and burette including the tap are clean, so there wouldn’t be any left-over chemical reacts with the solution which is going to be filled in them later. The second rinsing is with diluted sodium hydroxide solution. From the first rinsing, there will be some water drops left inside, if the solution of diluted sodium hydroxide is added into the burette or pipette directly without rinsing with it first, the concentration of NaOH will be changed to get lower as it will become more diluted. That leads to a decrease in concentration for the dilution and increase the titres. Hence, artificially increase the concentration of ethanoic
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When people’s eyelevel vary slightly to view the meniscus in a position slightly above the horizontal in a depression angle, the result recorded would become slightly smaller. It would cause a higher concentration of the sodium hydroxide vice versa.
The calibration of the weight scale used to weigh out the vinegar which is the ethanoic acid may be incorrect. If the weight of the acid is shown as a larger value, the calculation of ml/g would be affected and a smaller ratio (ml/g) would get. Vice versa, when the weigh gets scale smaller, the ratios (ml/g) of the calculation would get bigger. This will make some changes to the concentration calculation at the end as well. The same error may occur in all measuring equipment such as burette, volumetric pipette and volumetric flask.
The actual concentration of the sodium hydroxide solution could be different to what is written on the bottle. As sodium hydroxide is not a standard solution, the NaOH molecules will react with the carbon dioxide in the air . (NaOH + CO2 HCO3- + Na+) As the chemical NaOH is reacted, there will be less NaOH molecules left and it means that the concentration of it gets lower. As a result, when titrating the sodium hydroxide with the ethanoic acid, more sodium hydroxide solution is needed to react with the acid. The volume of sodium hydroxide increases and the ratio(ml/g) will gets bigger. Consequently, the results will higher than the true value which affecting the
We finally took 1ml of the 0.01% solution from test tube using the glucose pipette and adding it to test tube 4, we then used the H2O pipette and added 9ml of H2O to test tube 4 creating 10ml of 0.001% solution.
Next, making sure that the stopcock of the buret is closed, use a buret funnel to add 5-10mL of NaOH to the buret to rinse it. Drain all of the NaOH into the waste beaker by opening the stopcock. Rinse the buret in the same manner two more times.
For part C, the concentration of was determined to be 1.01 mol/L, 0.973 mol/L, and 1.158 mol/L. These results show a relatively closed to the accepted 1.00mol/L of NaOH. The differences of these results are understandable since the concentration of NaOH would changes over time because during the transfer of NaOH powder in part A, it was exposed to the air, thus it could reacts with CO2 in the atmosphere to produce Na2CO3 and water, therefore, changing the concentration of NaOH. Furthermore, the NaOH could also react with the glass thus it wills also reducing its concentration. However, all of the concentration of NaOH that was determine are maximum of 0.158mol/L differences compare to the standard 1.00 mol/L, therefore, it can be concluded that the result are accurate.
The objective of the experiment is to determine whether subjects with hyperopia or myopia have the same degree of lateral peripheral vision. Hyperopia, or farsightedness, occurs if a person’s eyeball is too short for the cornea, or if the cornea has to little curvature so that the light refracting is not focused in the eye correctly. This results in having trouble focusing or concentrating clearly on an object that are near to the person (http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/hyperopia ). Myopia, or nearsightedness, occurs when a person’s eyeball is too long or their cornea is curved too much. This leads to an incorrect refraction of the light and causes blurred vision when focu...
The molar volume of the H2 in our experiment is very close to the theoretical molar volume, but I think that the deviation lies in the temperature of the H2O: in the first trial it is too high and in the second one too low.
PART I. INTRODUCTION The molarity of an unknown acid will be determined using a method called "titration". Titration is the process of the gradual addition of a solution of known concentration to a second solution until the solute in the second solution has completely reacted. A solution of known concentration used in a titration is called a standard solution. In today's experiment, NaOH, a base, is the standard solution. Sodium hydroxide will be added to an unknown acid. The unknown acid and the base reacts and forms salt and water. This type of reaction is called neutralization: NaOH + HA ---> H2O + NaA HA is an abbreviation for an unknown acid. A substance called an indicator is added to show the end of the titration.
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
Extraction is a separation method that is often used in the laboratory to separate one or more components from a mixture. Sucrose was separated at the beginning because it is the most immiscible and it’s strongly insoluble. Next Acetylsalicylic Acid was separated which left Acetanilide alone. Variety steps could have led to errors occurring. For example the step of separation, when dichloromethane layer was supposed to be drained out, it could be possible some aqueous layer was drained with it. Which could make the end result not as accurate. Also errors could have occurred if possibly some dichloromethane was not drained out. Both way could interfere with end result of figuring the amount of each component in the mixture. The solids percentage were 22.1% more than the original. That suggests that solids weren’t separated completely which clarifies the reason the melting points that were recorded were a slightly lower than the actual component’s melting point. The melting point for Acetylsalicylic Acid is 136 C but that range that was recorded during the experiment was around 105 C to 118 C. The melting points were slightly lower than the literature value. Sucrose was the purest among all component due to its higher melting point which follows the chemical rule that the higher the melting point the more pure the component
One possible source of experimental error could be not having a solid measurement of magnesium hydroxide nor citric acid. This is because we were told to measure out between 5.6g-5.8g for magnesium hydroxide and 14g-21g for citric acid. If accuracy measures how closely a measured value is to the accepted value and or true value, then accuracy may not have been an aspect that was achieved in this lab. Therefore, not having a solid precise measurement and accurate measurement was another source of experimental error.
Then, we multiply the result by 100 to get a percentage number. An example calculation from the 5.00mL pipet is: ((5.00mL - 4.9178mL)/5.00mL)*100 = 1.6438%. The percent error allows us to see which type of glassware is the most accurate at measuring substances. From our results, we concluded that the variable auto pipettor was the most accurate, since it had the lowest percent error, at 0.0500%. The volumetric pipet, volumetric flask, and burette, all had similar percent errors at 1.0430%, 0.6394%, and 0.6619%, respectively. These results indicate that these glassware types are still very accurate. Next, the graduated cylinder had a percent error of 1.6400%, which is still relatively low, indicating that the graduated cylinder is also very accurate. The beaker and erlenmeyer flask both had higher percent errors, at 7.5218%, and 9.4146%, respectively. The beaker and the erlenmeyer flask were not accurate at measuring substances. This is perhaps because they are larger, and are meant to hold larger volumes of water, or they are meant to contain and pour substances. After finding out
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.
Compared to the 0.5 M hydrochloric acid that was less concentrated, the more concentrated 2 M hydrochloric acid c...
Detergent comes from the Latin word detergere meaning to clean, it is defined as a cleansing agent. Therefore, water itself is a detergent. This essay looks at soap and soapless (or synthetic) detergents. Both substances we use everyday and have a big market commercially, they effect everyone. Soaps are made from natural products and soapless detergents are produced chemically, each having advantages and disadvantages.
Initially, before any NaOH is added, the pH of H2C2O4 .2H2O is low because it contains mainly H3O+. The starting pH will, however, be higher for a weak acid, like H2C2O4 .2H2O, than for a strong acid. As NaOH is added, H3O+ is slowly used by OH- because of dissociation of NaOH. The analyte remains acidic but the pH starts to increase as more NaOH is added.
9. Slower distillation results in better separation of liquids, because time is needed for the liquids to meet the vapors in the distillation/condensation process. If this is done too fast, then the vapor doesn’t go through as many distillation/condensation cycles, and the final sample will not be separated into its too components as much.