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Hi, the amount of material (paradichlorobenzene) is not critical, but approximately twice the height of the thermometer bulb when molten. You want the water bath to be above the sample (about 250mL in a 400mL beaker). Paradichlorobenzene is what mothballs and some air fresheners, or urinal pucks, were made of, and they were very pure so that's an easy source of the material. Most modern mothballs and urinal pucks have been replaced with napthalene, which still works but isn't as good. It has too high a melting point. I used reagent grade paradichlorobenzene, and an air freshener from a local grocery store for comparison purposes. The air freshener was pink, so some groups got pink samples and others were clear. It made no measurable difference in melting point since the air freshener was 99.9% pure paradichlorobenzene.

That's to make the freezing point of water lower than it would otherwise be. It's a colligative property. You could freeze pure water this way too, but that wasn't the point of the lab.

@@troyboyd3100 Okay. Thank you! I know it wasn't the point of the lab, I was just wondering. If I was to use CaCl2 in both the test tube with the water and the ice water bath, would that have an effect?

@@julianna.roseeee4549 Oh, yup, the CaCl2 has a Van't Hoff factor of three, so that will lower the freezing point of the solution even further. Putting it in the water bath won't have much of an affect since that temperature is based on the original ice temperature (-20C in a standard freezer).

@@troyboyd3100 Okay. Thank you for your help!

That allows some of the ice to melt, providing better contact with the test tube. Although still at temperatures below -10C.

pause the video at 6:56 to see it in the data

SnowTiger45 k-spar is short for potassium feldspar. Potassium is represented by the letter K on the periodic table. It’s just easier to say lol. Amazonite, orthoclase, microcline, and a few others are all considered part of the k-spar family due to their potassium content.

tete hmsay cool

same, this guy a bum

pause the video at 6:56 to see it in the data

@@zacheus1 after two years. I asked the question for my bachelor's thesis. Now I am writing my master's thesis 😅

@@zacheus1 thanks for effort though! I really appreciate it 😊

I hope your observational skills have since improved....

@@zacheus1 😂😂😂😂

thank you.

I like to eat slate pencil

saittam eoj so were you scared??

yea how did it go??

Everyone is dying to know, were u scared?

Yeah 4 years later and we're still wondering

5 YEARS, SAITTAM EOJ WERE YOU SCARED?