A technique once used by geologists to measure the density of a mineral is to mix two dense liquids in such proportions that the mineral grains just float. When a sample of the mixture in which the mineral calcite just floats is put in a special density bottle, the weight is 15.4448g . When empty, the bottle weighs 12.4631g , and when filled with water, it weighs 13.5441g .

What is the density of the calcite sample? (All measurements were carried out at 25 Celcius , and the density of water at 25 Celcius is 0.9970 g/mL).

Question

A technique once used by geologists to measure the density of a mineral is to mix two dense liquids in such proportions that the mineral grains just float. When a sample of the mixture in which the mineral calcite just floats is put in a special density bottle, the weight is 15.4448g . When empty, the bottle weighs 12.4631g , and when filled with water, it weighs 13.5441g .


What is the density of the calcite sample? (All measurements were carried out at 25 Celcius , and the density of water at 25 Celcius is 0.9970 g/mL).

jfraser · Answer

All that info is telling you a couple of things. It tells you the mass of the special density liquid + bottle, and the volume of the special bottle itself.

Since the grains of mineral "just" float in the special density liquid, they must have the same density as the liquid itself. Use the pieces of info to find out:

The mass of the special liquid

The volume of the empty bottle

Divide those two, and you'll have the density of the liquid, and it will equal the density of the mineral sample.