Math CentralQuandaries & Queries


Question from Jordan, a student:

In Chemistry we are doing a lot of problems that are much more math related than anything. One of my questions reads: A certain medallion has a mass of 55.64 g. When placed in 75.2 mL of water in a graduated cylinder,
the water level rises and then reads 77.8 mL.
Is the medallion made of platinum (D=21.4 g/mL) or silver (D= 10.5 g/mL)?

This is due tomorrow, and I've already given up on actually getting this worksheet done, so all i really want to know is how to work out a problem like this. I don't even know where to begin, my teacher is about worthless to put it nicely. I have a test over this on Monday and I just really want to know how to work problems like these. Like how can i tell the density by how much water is displaced...oh idk. I just need help please. thank you


Hi Jordan,

By the fact that the water level in the graduated cylinder went up from 75.2 mL to 77.8 mL means that the volume of the medallion is 77.8 - 75.2 mL = 2.6 mL. Thus the medallion has a mass of 55.64 g and a volume of 2.6 mL so what's it's density?


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