In experiment 5, we are learning about density and specific gravity in measurements. Density is measured by mass divided by volume in order to get the ratio of the mass of an object to its volume. Specific gravity, on the other hand, is the density of a substance divided by the density of water and will cancel out the units in order to get a unitless measurement. Mass and Volume can be measured in two different ways, first mass can be calculated by directly placing it on the triple beam scale directly, or by weighing the difference. Volume can be calculated by displacement in the graduated cylinder or by calculating its dimensions. In this experiment, the objectives were to calculate the density of a solid by measuring its mass and volume, …show more content…
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. The second part of measuring for volume, we measured the density of Isopropyl alcohol the same way we did for the water. We measured the mass of the empty graduated cylinder which was 46.35 grams and then added 25.0 milliliters of Isopropyl alcohol to it which made the mass 66.95 grams, causing the difference to be 20.6 grams of the Isopropyl. This was 4.4 grams less than what it should have measured out to be. The last part of experiment 5, was learning about specific gravity and temperature. Specific gravity does not have any units, it is unitless. When measuring for the temperature, we used a thermometer to calculate the Celsius of the water, 10% sodium chloride, and isopropyl alcohol. The specific gravity uses a hydrometer to measure the gravity of the liquids. Using the hydrometer, to figure out the measurements we have to look at it from top to bottom. The water for specific gravity was .998 while the temperature of it was 24
Furthermore, using a graduated cylinder with markings below the 100 mL line would have allowed for more accurate measurements of the initial volume of air in the graduated cylinder.
The Gravimetric Stoichiometry lab was a two-week lab in which we tested one of the fundamental laws of chemistry: the Law of Conservation of Mass. The law states that in chemical reactions, when you start with a set amount of reactant, the product should theoretically have the same mass. This can be hard sometimes because in certain reactions, gases are released and it’s hard to measure the mass of a gas. Some common gases released in chemical reactions include hydrogen, carbon dioxide, oxygen and water vapor. One of the best methods for determining mass in chemistry is gravimetric analysis (Lab Handout).
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.
To begin the experiment, we measured 5cc of water and 5g of NaCl and added them to a test tube. Next, we stoppered the test tube and shook vigorously for two or three minutes. After we observed that the solution was saturated and massed an evaporating dish (18.89g) and poured most of the solution into it, while being careful not to pour any undissolved solid into the dish. Next, we massed the evaporating dish with the solution and found it to be 23.32g. The next step was to slowly evaporate the solution in the evaporating dish using a hot plate. Once the liquid was evaporated from the solution, to the best of our ability, we massed the remaining solid in the dish, which we found to be 20.32g. This was the last step of the physical portion of the experiment, and we proceeded to the calculations. First, we found the mass of the remaining solid by subtracting the mass of the evaporating dish from the mass of the solid and evaporating dish, which we found to be 1.43g. To find the mass of the evaporated water we subtracted the mass of the solid and evaporating dish from the mass of the solution and evaporating dish, which we found to be 3g. Because the density of water is 1g/1cc, the mass is the ...
To make my results as accurate as possible I will be using a balance that can measure to two decimal places, and a thermometer that is capable of measuring to half a degree Celsius. To make sure my results are as reliable as possible, I will repeat each alcohol three times.
It was then placed in the ice bath, in which immediately the can slightly collapse on itself. In part two of the experiment, the prepared ice bath temperature measured at 1°C (T2). While the heated bath temperature stabilized around 85°C (T1) after 5 minutes, where it also began to simmer. The test tube with the rubber stop in the heated bath had no water for the entire 5 minutes. When the test tube was placed inside the ice bath for 5 minutes water appeared to flow inside the test tube. The amount of water that flowed into the test tube measured at 5 mL (Vw). When determining the volume of the test tube in the 100 mL graduated cylinder with 30 mL of water, it displaced the water up to 74 mL. Thus determining the volume of the test tube as 34 mL
Measure the weight of a small stone to fit inside the opening of a 50ml graduated cylinder.
The cold pack experiment lab allowed us, the students, to apply theories learned in class to actual real life experiments; such experiments prepare us for future tasks the will be put forth to determine. Our main trajectory through this assignment was to determine what our unknown salt was, through experimental analysis. The main purpose of this lab was for us to determine what the given unknown salt is. For this experiment, my group and I were given unknown salt 7. Information recognized before starting the lab, were the materials needed, background information on the math required to determine the unknown(s). In addition, other background sources before starting the experiment included having previous knowledge of chemical formulas, understanding concepts learned throughout class and how a calorimetry works. Furthermore in order to determine how to complete the lab, we needed information upon how to properly keep the temperature of the water from decreasing or increasing, and this required that we needed to know what an insulator is and how to use ...
6. Determine the volume of water that has been displaced, by subtracting the initial volume of water from the final volume (VF) after adding 25 germinating peas. The difference in volume is
After finishing the trials, our group subtracted the mass of the glassware without water from the mass of the glassware with water in order to find the mass of the water in grams. Then, we divided the mass of the water by the density(g/cm^3) of the water in order to find the volume (mL). An example calculation from the 5.00mL pipet is: (4.9285mL+4.8839mL+4.9367mL+4.9265mL+4.9134mL)/5 = 4.9178. In most cases, the temperature of the water was around 23 degrees celsius, making the density about .998408 g/cm^3 for many of the trials. The densities we used were found online. The next calculations we performed were to determine the average volume of the water in each person’s five trials by adding up all of the volumes(mL) and dividing that number by five. Using the average volume, we then calculated the
I am going to carry out an experiment to measure the change in mass of
Variables --------- During the experiments, the water will be heated using different spirit burners containing different alcohols. I will be able to change different parts of the experiment. These are the. Volume of water heated:
...inty between 1.0% (0.1/10.00*100) and 2.13% in the measured volume and 0.1/4.70*100). We also used a digital thermometer that allowed us to read the temperature readings from five degrees celcius to eighty degrees celcius. Since the digital thermometer have an absolute accuracy of plus or minus one degree celcius, it gives a percent uncertainty between 0.125 % (0.1 / 5.00 * 100) and 0.2 % (0.1/ 80.0 * 100). One of the difficulties we faced during the lab is reading the inverted graduated cylinder. To account for the inverse meniscus, we subtracted 0.2 mL from all the volumetric measurements to account for that. Volumetric uncertainty is the most important in determining the accuracy of this experiment since we are constantly checking for the volume throughout the lab. It also is the factor that gives the highest percent uncertainty out of all the instruments used.
Any chips caused by dropping or misuse of the instrument can cause a change in mass. Additionally, when dealing with some liquids there can be a chemical affinity between the liquid and the stem, depending on the material of which the hydrometer is composed. This can cause a buildup of material on the stem, altering the mass and thereby rendering the instrument out of calibration.