Concept: The purpose of this lab is to determine the density of a solid and an unknown liquid in order to determine the unknowns from a list of substances provided in the lab instruction. A method to identify the substance is to figure out the density (d=m/v) where d is the density equals to the mass divided by the volume of the substance. When measuring the mass, reset the balance to zero to obtain only the mass of the object in grams (g) and not anything else. When measuring the volume, read at the meniscus for an accurate measurement. Procedure: We obtained an unknown metal with an identification number (6) from the instructor. Make sure not to get fingerprints on the sample otherwise it will interfere with identifying the density of …show more content…
the substance. We tared a weighing boat on the balance and weigh all of the metals provided. Then we recorded the mass in grams (g) which was 28.923(g). Next we proceed to find the volume of the unknown metal. We added 30.0-mL (milliliters) of water to a 100-mL graduated cylinder. We then titled the graduated cylinder about 45 degrees and slide in the metals to avoid breaking the graduated cylinder or splashing out the water. If there are air bubbles present inside the water, tap the graduated cylinder gently on the table to get rid of the bubbles. We put an index card behind the graduated cylinder and read at the meniscus to get a more accurate measurement. We recorded the volume of the metal to the nearest 0.1 milliliter which was 4.9-mL. Then we drain out the water and clean the graduated cylinder. We calculated the density of the unknown metal by taking the mass and dividing it by the volume. We took the volume of water in the cylinder, 30-mL, and subtracted the displacement in water made by adding in the unknown metals. We got 4.9-mL for the volume of the unknown metals. We took the mass of the unknown, 298.923(g), and divided it by the volume, 4.9-mL, and got 5.9(g/mL) for the density. We then try to identify the metal by looking for the closest density of the known metals given by the chart of known metal densities. The closes one to our density was zinc with a density of 7.14. We did our percent experimental error (%error = ((experimental value – theoretical value)/theoretical value)*100) by taking our experimental value, 5.9(g/mL), and subtracting it from the theoretical value, 7.14(g/mL). We got a value of -1.24. We then took that number and divided by the theoretical value, 7.14(g/mL). We then multiply that value and got a percent error of -17% error. Next we needed to identify the mass and volume of the unknown liquid (5) obtained also form the instructor.
We used a crucible tongs to place a dry, empty graduated cylinder on a zero out balance. We recorded the mass of it which was 26.30(g). After we pour 3.14-mL of the unknown liquid into the graduated cylinder; this is sample 1. We used the same procedure to read the graduated cylinder of the unknown metal by reading it at the meniscus with an index card from behind. We recorded the volume. We then weigh the first sample and recorded the mass to be 28.64. Do not remove the first sample from the graduated cylinder. Next we added an additional 3-4-mL of the unknown liquid to the first sample. The combine number is 7.35-mL to the nearest .01-mL for sample 2. We then recorded the mass of the unknown sample, 32.14(g), in grams on a balance. Again, do not pour out the unknown liquid from the graduated cylinder. We added more of the unknown liquid until it was nearly but not over 10-mL. We recorded the volume for sample 3 to be 9.39-mL. Then weigh the sample to be 33.78(g). Pour the liquid back into the original container; do not pour the liquid down the …show more content…
sink. We calculated the masses for the three unknown sample by subtracting the sample mass of the graduated cylinder from the initial mass of the dry graduated cylinder.
For sample 1, we subtracted 28.64(g) from 26.30(g) and got a mass of 2.34(g). We did the same process for the rest of the samples and got a mass of 5.84(g) (32.14(g) – 26.30(g)) for sample 2 and 7.49(g) (33.78(g) – 26.30(g)) for sample 3. We divided the mass of the each samples by their own volumes. For sample 1 we divided 2.34(g) by 3.14(mL) and got a density of .745(g/mL). We did the same process for the other samples and got .795(g/mL) (5.84(g)/7.35(mL)) for sample 2 and .797(g/mL) (7.49(g)/9.39(mL)) for sample 3. We then add up all the densities of the sample and then divided by 3 to get the average density, .779(g/mL). The identity of the unknown liquid (5) was cyclohexane which has a density of .792(g/mL). We had to calculate the percent experimental error just like the unknown metal. We took .779(g/mL) minus .792(g/mL) and then divided it by .792(g/mL). Then multiply the product by 100 and got -1.64% error. After calculating all the values, we put it in a graph to compare the density, mass, and volume by using
MicroLab.
The mixture was poured through a weight filter paper and Sucrose washed with a 5ml of dichloromethane. The resulting solid was left in a breaker to dry for one week, to be measured. Left it in the drawer to dry out for a week and weighted it to find the sucrose amount recovered amount.
Regarding the densities of Coke and Diet Coke, I believed that the density of coke would be greater than the density of Diet Coke. Because the content of Coke contains more sugar than Diet Coke, it would contain more mass and since density is mass dependent, Coke would be denser than Diet Coke. From the results of the experiment, there was a slight difference between the densities of Coke and Diet Coke. The measurements obtained from the pipette and the graduated cylinder demonstrated that Coke is denser than Diet Coke while Diet Coke was shown to be denser than Coke using the burette. With the pipette, the average density of Coke is 1.02 and the average density of Diet Coke is 0.99. With the graduated cylinder, the average density is 0.976968 and the average density of Diet Coke is 0.95. With the burette, the average density of Coke is 0.99 and the average density of Diet Coke is 1.0. Among the three instruments, the most precise was the graduated cylinder and the most accurate was the volumetric pipette. Since density is defined as mass/volume, changing the volume of Coke or Diet Coke would have changed.
I am going to carry out an experiment to measure the change in mass of
Stick the impressions onto a slide, and observe the number of stomata in the area you have selected. Record the density on the table made in the earlier steps. Make sure to change the area after every reading to get a more accurate reading.
The purpose of this lab was to practice the skill of gravimetric analysis to determine the concentration of an analyte in a solution. The objective of this lab was to determine the amount of phosphorus in a sample of plant food compare that to the amount labeled on the container, which was 30%. In order to get the mass of phosphorus by itself, 2.5 grams of 10% liquid MgSO4 and 25 mL of ammonium was mixed with the liquefied form of the plant food in order to create a precipitant. This precipitate was the analyte that was needed to be extracted from the solution. After waiting 45 minutes for the phosphorus to settle to the bottom, the solution was filtered through a filtering paper and excess water was collected in the cup. When filtration was
Lab partner 1 should get sugar in weigh boat and weigh it (4x). Lab partner 2 set up measurenet.
Obtain a sample of metal that has been immersed in boiling water and place it in the cup of water.
Originally, I was supplied with 30 cm of copper wire and a test tube. First, the wire was cleaned with steel wool.The copper wire was coiled around the full length of the test tube. The copper was then weighed. Then an empty 250 ml beaker that was labeled by my partner was weighed. A vial of white silver nitrate was also weighed. After, 2/5th of the clean beaker was filled with distilled water and the solid silver nitrate was stirred in with the water until the crystals that were formed dissolved. Then the end of the copper wire was bent so we could submerge the coil in the solution and still be able t...
The experiment was luckily conclused fairly similar to the accepted value. However, because only appoximation of datas and other source of errors, the accuracy of the data could be questionable.
Weigh out two 0.100 g. samples of the product and put each into a test
Density is a radiographic property that affects the detail of the radiograph by determining the overall blackness on the film (Adler, 2013). The major governing factor for density is mAs; mAs is found by multiplying the milliampere by the time, which is recorded in seconds (Adler, 2013). The density of an image is directly proportional to the technical factors of milliampere per second (Bushong,2013). The optical density can be measured with the use of a densitometer, which will give density a numerical value (Bushong,2013). Milliampere per second is the primary controlling factor for density, and mAs can be manipulated to maintain density when there are other factors such as kVp influencing the radiographic density.
Part A of the experiment, we were measuring the density of water. In this part, we measured by difference by measuring the mass of the empty graduated cylinder which was 46.35 grams and then added 25.0 milliliters of water to it. When subtracting by difference, our mass of the water was 25.85 grams. This was close to the measurements of the water added to the graduated cylinder. The density of the water was 1.0 grams/milliliters.
This experiment is designed to educate proper techniques for using an analytical balance and volumetric apparatus’s. Accuracy in volume measurements are significant in analytical chemistry but all volumetric glassware have errors and obscurities linked with the measurements observed. Miniscule damage in a glassware due to aging, abuse and chemicals can create systematic errors in the observational measurements. Volumetric pipets and burets can be used for fairly accurate measurements if they’re standardized correctly. The purpose of this exercise is to measure volume and mass, to evaluate precision of the measurements, and to use the data to calculate the density or standard deviation. This experiment is achieved by first weighing the mass of a coin, mass of weighing paper and then measure both objects together to obtain the average mass of a coin. Following the introduction of calibrating with an analytical balance, we are given the volume of water to transfer into an Erlenmeyer flask or beaker by pipet/buret to obtain the actual volume delivered using the density of water at the given temperature. The process will be repeated three times for each given volume of water. Correspondingly, I will assess the error in the ability to read the glassware accurately by calculating a combined standard deviation of the total mass of the coin, the tolerance level for each volume delivered of water, and the density of water.
The first major property of fluids that is used in many types of applications is the fluids’ density. In engineering, density can be sub-divided into three types which are mass or mean density, specific weight, and also relative density or specific gravity. Mass or mean density is the most commonly used type of density and it is denoted by the Greek symbol r (rho) in units of kilogram per unit volume (kg/m3) (Munson, Young, Okii...
I have also seen use of fluid dynamics in the where they should look after the density for