Experiment 2: a Memo from Corporate Accuracy and Precision of “Volumetric” Glassware

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.

There are several sources of error to this experiment due to random and systematic errors. The only source of random error was the measurement that we took through the graduated cylinder which was only accurate to the nearest 1%. We took the largest error from this one percent, which was +/- 3. The largest relative error this yielded was only 3%, so this did not affect how precise this experiment was too much. We can still make this more precise by making the masses of the water larger. For example if we started the masses at 300mL and went up by 50mL, the largest error this would yield would be 2% due to the largest error being +/- 5. This would cause smaller errors in the amount of water.

First, I will get my materials and set up the scale and 10 mL cylinder and refraction cell. I will check the size of the graduated cylinder to find out the volume. (LxHxW) That will equal 40.5mL for volume. I will see how much the cell weighs alone, and then I will 0 out the scale to see how much the water weighs. Then I will see how much the water and the cell weigh together. I will do this for the cell and cylinder. I will check to see if the density I calculated is what it is supposed to be at 1.00.

I took the graduated cylinder and started filling it up with water until the bottom of the meniscus was to the the 100.0 mL mark with the assistance of a dropper pipet. I then took the 13 x 100 mm test tube and slowly poured the water from the graduated cylinder into the test tube until it was full to the top. I then poured the water in the test tube out into the sink and put the graduated cylinder on the counter so I can get an accurate measurement of the lower meniscus to record on my data table. I once again followed the same procedure again filling a second test tube with water from the graduated cylinder then setting it on a straight surface to get an accurate measure of the volume to

First students obtained 8 graduated cylinders and labeled them. Each one contained a different ratio of vinegar and water. These graduated cylinders with the liquid were weighed and recorded.Then, students obtained an Alka-Seltzer tablet and recorded its mass. Then one alka-seltzer tablet was dropped into each of the graduated cylinders. Students had to

15. Which parameter of glass is measured with bromoform and bromobenzene mixtures in a column?

A. Water boils at 100°C at sea level. If the water in this experiment did not boil at 100°C, what could be the reason?

Since a graduated cylinder is usually used for liquid measurement, students think they need to put water in the cylinder. This is not

Abstract: The objective of the lab is to determine the volumes of the polystyrene spheres with three different measuring tools: Water Displacement, Analytical Scale, and Triple Beam Balance Scale. The experiment is meant to help understand the concept and application of precision and accuracy in experimental measurements. Accuracy is a measure of how closely the results of repeated measurements are to the true value of what is being measured. Precision is the variability in the results from the repeated measurements, and how close the repeated measurements were to one another. In this lab, the method for measuring the volume of the polystyrene spheres is done with the previously stated tools: Water Displacement, Analytical Scale, and Triple Beam Balance Scale. The standard deviation for the entire classes volumes and masses are recorded to determine the densities.

In the third stage of this experiment, the density of a liquid was determined and compared to known standards. A 100ml beaker was filled to about half-full with room-temperature distilled water. The temperature of the water in ◦C was recorded in order to compare to known standards later. A 50ml beaker was then weighed on a scale in order to determine mass and recorded. A sample of the distilled water with an exact volume of 10ml was then placed in the 50ml beaker using a volumetric pipette. The 50ml beaker with the 10ml of water was then weighed again and the initial mass of the beaker was subtracted from this mass to obtain the mass of the 10ml of water. With the volume and the mass of the water now known, density was calculated using d = m/V and recorded in g/ml. This process was then repeated to check for precision and compared to standard values to check for accuracy. Standard values were obtained from CRC Handbook, 88th Ed.

The experiment is repeated twice and an average is obtained. This ensures the consistency of the measurement as the reading is triplicated, thus reducing anomalies. It can be seen that the reading obtained were around the same value. This proves that the results are reliable.

Abstract: This experiment introduced the student to lab techniques and measurements. It started with measuring length. An example of this would be the length of a nickel, which is 2cm. The next part of the experiment was measuring temperature. I found that water boils around 95ºC at 6600ft. Ice also has a significant effect on the temperature of water from the tap. Ice dropped the temperature about 15ºC. Volumetric measurements were the basis of the 3rd part of the experiment. It was displayed during this experiment that a pipet holds about 4mL and that there are approximately 27 drops/mL from a short stem pipet. Part 4 introduced the student to measuring

(with lids & gauge). It showed that there was significant difference between the two situations that

The volume of a small test tube and a thin-stemmed pipet were determined in this section of the lab. Water was poured into a small test tube until the water reached the very top edge of the test tube. The test tube was then emptied into a plastic 25 mL graduated cylinder and volume was measured and recorded into data table 3. A think-stemmed pipet was completely filled with water. Drops were carefully counted and emptied into the empty plastic 25 mL graduated cylinder until the water level reached 1 mL. The number of drops in 1 mL was recorded into data table 3. The thin-stemmed pipet had a total volume of 4 mL and that was also recorded into data table 3.

In this experiment, The purpose of this experiment is to investigate the measurement of the actual volume contents of volumetric glassware. In the beginning of the experiment, the volumetric glassware should be clean and dry before used. The volumetric glassware, measuring cylinder and pipette should be handled with care and all the precautions were be taken during the experiment was held. This was to ensure to avoid any errors such as parallax error especially while reading water meniscus. This experiment must be repeated three times or more and take the average reading to get more