ensity of Unknown Liquid:
Lacy obtained a dry empty flask with a stopper and placed it on an analytical balance. She found the mass to be 36.765 g. Lacy then completely filled the flask with distilled water and forced all the air out with the stopper. She again weighed the stopper, flask and water and obtained a mass of 65.264 g. She determined the volume of the flask. She emptied and dried her flask and obtained her unknown liquid, which was in a flask labeled "number 1". She completely filled the flask with her unknown liquid, placed the stopper on as before and obtained a mass of 59.323 g. From this and previous data, she was able to determine the density of her unknown liquid.
Density of Unknown Metal:
Lacy emptied and dried her flask and obtained a sample of unknown metal which was labeled "#14". She poured her metal sample into her flask with a stopper and placed it all on the analytical balance. She obtained a mass of 90.04 g. She then filled the remaining volume of the flask with water, making sure that there were absolutely no air bubbles remaining when the stopper was placed on as before. Lacy weighed the flask, stopper, water, and metal and obtained a mass of 111.400 g. With this data, Lacy obtained the information necessary to determine the density of her unknown metal.
A. density of unknown liquid
1) mass of the empty flask plus stopper
2) mass of stoppered flask plus water
3) mass of stoppered flask plus unknown liquid
4) mass of water
5)temperature in the lab
6) volume of flas (density of h20 at 25 degrees c 0.09970 g/cm^3 at 20 degrees c 0.9982 g/cm^3)
7) mass of liquid
8) density of liquid
B. Density of unknown metal
Mass of stoppered flask plus metal -- __________________g
Mass of stoppered flask plus metal plus water -- __________g
Mass of metal --------------------------------___________g
Mass of water --------------------------------___________g
Volume of water ------------------------------___________cm3
Volume of metal -------------------------------__________cm3
Density of metal -------------------------------__________g/cm3
Unknown solid no. -----------------------------___________
https://www.khanacademy.org/science/chemistry
Lessons to help you catch up!
Follow these steps for the density of the unknown liquid. I can't put in numbers since you didn't show the temperature of the lab. Without the temperature of the lab I don't what to use to the density of the water at 20 C or 25. Another problem is please check the value of density of water at 25 C. I think that preceding 0 is a typo.
65.264 g = mass empty flask, stopper
-36.765 g = mass flask, stopper, filled with water
-----------------
28.499 g = mass water in the flask. Now you determine the volume of the flask. mass water = volume water x density water.Obriously the volume of the water in the flask = volume of the flask.
Plug in 28.499 for mass water, plug in the density. It's obvious what to use for density IF it is 20 C or 25 C. If it is not one of those values you interpolate. Find the difference between density at 25 C and 20 C, divide the difference by 5 to determine the change in density per degree C then convert that to the temperature of the lab. Finish the mass = volume x density calculation and you have the volume of the flask. My assumption is that you filled you ORIGINAL FLASK (the one that weighed 36.765 g) with the unknown liquid. Now you have weighed the flask, stopper, unknown liquid.
59.323 g = mass flask, stopper, unknown liquid
-36.765 g = mass empty flask and stopper
-----------------------
22.558 g = mass unknown liquid.
mass unk liquid = volume unk liquid x density liquid.
You know mass of liquid and volume liquid, solve for density liquid.
Please confirm ll of these numbers and calculations.My eyesight isn't that good and make a lot of typos. I've check this over but that isn't a sure thing.
I'll leave the unknown metal to you. It's done much the same way.
By the way, you can tell your lab instructor that you think the unknown liquid is ethanol.
I need help with this. How much have you done on your own? Have you filled out the tables but left them blank on this post?
I noticed the same thing in Lexy's earlier post -- complicated questions, no effort on her part.
https://www.jiskha.com/questions/1803465/Please-help-I-dont-know-how-to-do-any-THE-EXPLANATION-Lacy-obtained-a-dry-empty
Lexy, if you feel this lost in this class, you probably should see about dropping it and re-taking your last science class so you can catch up.
lol how can i drop a class senior year? wild right to assume i have no effort. Like i said in my post, I need help getting started not the anwsers lol.
the mass of the unknown stopper plus metal 53.275
mass of stopper flask metal and water 111.400
mass of water 28.499
volume of water 28.499
To find the density of the unknown liquid:
1) The mass of the empty flask plus stopper is 36.765 g.
2) The mass of the stoppered flask plus water is 65.264 g.
3) The mass of the stoppered flask plus unknown liquid is 59.323 g.
4) The mass of water can be calculated by subtracting the mass of the empty flask plus stopper from the mass of the stoppered flask plus water: 65.264 g - 36.765 g = 28.499 g.
5) The temperature in the lab is not necessary for the calculation of the density of the unknown liquid.
6) The volume of the flask can be obtained from the previous data of the mass of water. Since the density of water at 20 degrees Celsius is 0.9982 g/cm^3, the volume of water can be calculated by dividing its mass by its density: 28.499 g / 0.9982 g/cm^3 = 28.56 cm^3.
7) The mass of the unknown liquid can be calculated by subtracting the mass of the empty flask plus stopper from the mass of the stoppered flask plus unknown liquid: 59.323 g - 36.765 g = 22.558 g.
8) The density of the liquid can then be calculated by dividing the mass of the unknown liquid by its volume: 22.558 g / 28.56 cm^3 = 0.790 g/cm^3.
Therefore, the density of the unknown liquid is 0.790 g/cm^3.
To find the density of the unknown metal:
1) The mass of the stoppered flask plus metal is 90.04 g.
2) The mass of the stoppered flask plus metal plus water is 111.400 g.
3) The mass of the metal can be calculated by subtracting the mass of the stoppered flask plus metal from the mass of the stoppered flask plus metal plus water: 111.400 g - 90.04 g = 21.360 g.
4) The mass of water can be obtained from the previous data: 28.499 g.
5) The volume of water can be calculated by dividing the mass of water by its density, which is known to be 0.9982 g/cm^3 at 20 degrees Celsius: 28.499 g / 0.9982 g/cm^3 = 28.56 cm^3.
6) The volume of the metal can be obtained by subtracting the volume of water from the volume of the flask: Volume of metal = Volume of flask - Volume of water. The volume of the flask can be calculated using the density of water at 20 degrees Celsius: Volume of flask = Mass of flask / Density of water = 36.765 g / 0.9982 g/cm^3 = 36.82 cm^3. Therefore, Volume of metal = 36.82 cm^3 - 28.56 cm^3 = 8.26 cm^3.
7) The density of the metal can then be calculated by dividing the mass of the metal by its volume: 21.360 g / 8.26 cm^3 = 2.58 g/cm^3.
Therefore, the density of the unknown metal is 2.58 g/cm^3. The label of the unknown solid is "#14".