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. -----------------------------___________
5 answers
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.
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
Lessons to help you catch up!
65.264 g = mass empty flask, stopper
-36.765 g = mass flask, stopper, filled with water
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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
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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.
0 answers