A laboratory technician measures the densities of four sealed vials that each contain…

CHEMISTRY · Multi-part · CBSE · Chemistry · The Amazing World of Solutes, Solvents, and Solutions · The Amazing World of Solutes, Solvents, and Solutions

Problem

A laboratory technician measures the densities of four sealed vials that each contain a different pure liquid at

20^{\circ}\text{C}

. The measured densities are listed below. • Vial 1:

0.88\,\text{g/cm}^3

• Vial 2:

1.13\,\text{g/cm}^3

• Vial 3:

0.79\,\text{g/cm}^3

• Vial 4:

1.26\,\text{g/cm}^3

A reference handbook gives the following tabulated densities (all at

20^{\circ}\text{C}

): Ethanol

0.79\,\text{g/cm}^3

Mineral oil

0.87\,\text{g/cm}^3

Saltwater (3.5 % by mass)

1.03\,\text{g/cm}^3

Glycerin

1.26\,\text{g/cm}^3

Propylene glycol

1.04\,\text{g/cm}^3

Answer the following questions about the identity of the liquids in the vials. (a) For each vial, state the most probable substance contained in the vial based on the measured density and the reference data. (b) Describe the reasoning that allows you to match each measured density to a particular substance. In your answer, refer explicitly to the physical property that makes the identification possible. (c) Discuss two experimental factors (other than arithmetic mistakes) that could cause an incorrect identification in part (a), and explain qualitatively how each factor would affect the measured density.

Related theory

Density

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