A pycnometer is a glass apparatus used for accurately...

A pycnometer is a glass apparatus used for accurately determining the density of a liquid. When dry and empty, a certain pycnometer had a mass of $27.314 \mathrm{~g}$. When filled with distilled water at $25.0^{\circ} \mathrm{C}$, it weighed $36.842 \mathrm{~g}$. When filled with chloroform (a liquid once used as an anesthetic before its toxic properties were known), the apparatus weighed 41.428 g. At $25.0{ }^{\circ} \mathrm{C},$ the density of water is $0.99704 \mathrm{~g} / \mathrm{mL}$. (a) What is the volume of the pycnometer? (b) What is the density of chloroform?

Key Concepts

Pycnometer

A pycnometer is a precision instrument used to determine the density of liquids by containing a fixed, accurately measured volume. Its design allows for the weighing of the container when it is empty and then when it is filled with a liquid of known density, providing the information necessary to calculate the container's internal volume or the density of another liquid.

Density

Density is a physical property defined as the mass per unit volume of a substance. It is typically expressed in units such as grams per milliliter or kilograms per cubic meter and is calculated using the formula ? = m/V. Density is essential for identifying substances and understanding their behavior under various conditions.

Mass-Volume Relationship

The relationship between mass, volume, and density is fundamental in chemistry and physics. Knowing any two of these quantities allows one to calculate the third. This relationship is especially utilized in experiments involving liquid densities, where precise measurements of mass and volume lead directly to the determination of density.

Volume Calibration

Volume calibration involves determining the exact volume of an instrument, such as a pycnometer, by filling it with a liquid of known density. By measuring the mass of the calibration liquid, the volume of the instrument can be accurately calculated. This calibrated volume can then be applied to determine the density of other liquids with subsequent mass measurements.

Transcript

00:01 In this problem of scientific measurement, we have given that a pykno meter is a glass apparatus used for accurately determining the density of a liquid when dry and empty.

00:16 A certain pykno meter has a mass of this is when dry and empty.

00:22 So this would be dry and empty.

00:26 The mass is equals to this is 36 point.

00:31 This has a mass of 27 .314 grams so this is 27 .314 grams when filled with distilled water at 25 degrees it weighed so when filled with distilled water mass is say this would be m2 this is equals to 36 .842 this is 36 .842 grams and this is at 25 degrees celsius.

01:14 When filled with chloroform a liquid once used as an anesthetic before it was, it has toxic property were known.

01:22 So the apparatus weight, so when filled with chloroform, the mass 2, so this would be m3, so this is the mass 3.

01:45 So m3 is equal to 41 .48, this is 41 .48 grams and this is as a at again 25 degrees celsius.

01:59 The density of the water is, so we have given density of water, say dw is 0 .99, this is 0 .997.

02:09 Grams per milliliter at 25 degrees celsius.

02:16 So at 25 degrees celsius.

02:19 What is the volume of the pycometer and also what is the density of the chloroform? so first part a.

02:29 In order to determine the volume of the pykno meter, we need to determine the volume of the water that fills it.

02:38 And we will do this by using the mass of the water and its density.

02:43 So mass of the water is here.

02:45 So this would be mass of water, mw, is equal to mass of the filled pykno meter.

02:51 So this would be m pygnometer.

02:55 This is filled pykno pykno meter minus mass of the so this would be here filled with so this is filled minus mass of the picnometer when this is empty, dry and empty...

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