Laboratory Assignment: Using a Top Loading Balance
1.How is the balance turned on?
To turn on the top loading balance, press down on the bar that is on the front of the machine.
2. Write a complete and accurate procedure for weighing a chemical on the top loading balance.
To weigh a chemical using the top loading balance, follow these steps:
a. Press the bar on the front of the machine to turn on the balance
b. Wait for the digital display to read “0.00 g” (grams)
c. Place a weighing paper on the pan of the balance
d. Zero out the scale by pressing the bar on the front of the machine
e. Using the paper to hold the substance, place the solid chemical on the pan to be weighed
f. Check the display for the mass of the chemical
…show more content…
To weigh a chemical by difference in a volumetric flask, follow these steps:
a. Place the volumetric flask on the pan of the top loading balance.
b. Zero the scale by pressing on the bar on the front of the balance.
c. Transfer the chemical into the volumetric flask using a powder funnel and the appropriate tools to remove the chemical from the storage container.
d. Place the volumetric flask, now holding the desired amount of chemical, onto the scale.
e. The mass of the chemical (in grams) in the flask will show on the display on the balance.
f. You are basically to subtract the weight of the beaker with the chemical from the weight of the beaker empty. The difference is the weight of the chemical sample.
7. Why is this procedure more accurate than the previous procedure? Make sure your answer is complete and thorough.
The weighing by difference method of measurement is more accurate than the previously described method of weighing directly on the pan using a weighing paper. When using the weighing paper on the pan method, it is impossible to know for certain if the balance readings are accurate. Inaccuracies can occur due to of lack of proper scale calibration. Using the difference method, it does not matter if the scale calibration is off because the difference between the weight of the empty vessel and the weight of the vessel with the chemical is the actual weight of the sample. In summary, the difference between
First I will set up the apparatus as show above. I will add 1.5 grams
Next, I poured distilled water just below the 250ml mark on the neck of the volumetric flask.
11. Tare the scale by pressing the Φ/T button so that the scale reads 0.0 g.
1. Move the lid of the container up or down. Record the resulting volume and pressure
0.1 gram of my product from the second trial was weighed in a tray and was then added to a fourth test tube containing 2.0 mL of Iron (III) chloride, which was measured using a 10 mL graduated cylinder, to test for
In the fourth stage of this experiment, the density of a gas was determined. A 250ml flask was weighed with an empty rubber balloon and the mass was recorded.
The weight of each 50ml beaker (used for weighing the mass of dissolved Potassium chloride after the evaporation of water) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a source of error.
2. Fill a flask with pure water (0% sugar), another with 0.2M water, another flask with 0.4 M water, and another flask with 0.8M water.
Benzyltriphenylphosphonium chloride (0.201g) and 9-anthraldehyde (0.116g) were weighed and added to a short-neck round-bottomed flask (5ml). Dichloromethane (2ml) was measured using a measuring cylinder and added to the
XII. Take the 250 ml beaker to your lab bench. Set up a gravity filtration with a plastic funnel, folded wet filter paper, and an Erlenmeyer flask. Pour the content in the 250 ml beaker slowly through the filter paper. Wash the filter paper with deionized water. Dispose of the filtrate in the proper labeled waste container.
The purpose of this lab was for the student to get involved with his or hers new lab kit as well as being able to know, identify and use each other tools provided in the kit. Another key learning aspect of this lab is to teach the student how to measure properly the many units in the SI system. I will be using laboratory dilutions, measurements, and weights to then calculate using algebraic formula.
The purpose of this lab was to become familiar with the three different balances and two different methods used to find the weight and mass of chemicals and compounds in the ChemLab program. The lab was performed by using three different types of balances, and the direct weighing and weighing by difference methods.
Determine the weight of the water by subtracting the weight of the vial with water by the weight of the vial on its own.
One milliliter of 6.00-M phosphoric acid was placed into a 125-mL Erlenmeyer flask using a volumetric pipette. Using a slightly larger pipette, six milliliters of 3.00-M sodium hydroxide was transferred into a 50-mL beaker. Then a disposable pipette was used to slowly mix the sodium hydroxide into the phosphoric acid while the solution was swirled around. Then both the beaker and flask were rinsed with 2-mL of deionized water and set aside. A clean and dry evaporating dish was weighed with watch glass on a scale. Then the solution was poured into the dish and the watch glass was placed on top. The solution was then heated with a Bunsen burner to allow for the water to boil off to reveal a dry white solid. After the dish cooled to room temperature it was once again weighed and the new mass was recorded.
Record the sample mass in your notebook. Remember to record all digits on the balance. Closed toed shoes and goggles are REQUIRED for the lab