Question

In the process of attempting to characterize a substance, a chemist makes the following observations: The substance is a silvery white, lustrous metal. It melts at 649 \({ }^{\circ} \mathrm{C}\) and boils at \(1105{ }^{\circ} \mathrm{C}\) Its density at \(20{ }^{\circ} \mathrm{C}\) is \(1.738 \mathrm{~g} / \mathrm{cm}^{3} .\) The substance burns in air, producing an intense white light. It reacts with chlorine to give a brittle white solid. The substance can be pounded into thin sheets or drawn into wires. It is a good conductor of electricity. Which of these characteristics are physical properties, and which are chemical properties?

Short answer

The physical properties of the substance include its silvery white, lustrous appearance, melting point (649 ºC), boiling point (1105 ºC), density (1.738 g/cm³), malleability, ductility, and conductivity. The chemical properties include its reaction with air, producing intense white light, and its reaction with chlorine to form a brittle white solid.

Step-by-step solution

Characteristic 1 - Color and appearance

The substance being a silvery white, lustrous metal is a physical property because this can be observed without changing the composition of the matter.

Characteristic 2 - Melting point and boiling point

The melting point (649 ºC) and boiling point (1105 ºC) of the substance are both physical properties, as these points can be observed and measured without altering the composition of the substance.

Characteristic 3 - Density

The density (1.738 g/cm³) is a physical property, as it can be measured and calculated without altering the composition of the substance.

Characteristic 4 - Reaction with air

The substance burning in air and producing intense white light is a chemical property, as it involves a chemical reaction between the substance and the oxygen in the air.

Characteristic 5 - Reaction with chlorine

Reaction with chlorine to give a brittle white solid is a chemical property because the substance is undergoing a chemical reaction as it binds with the chlorine.

Characteristic 6 - Malleability and ductility

The substance's ability to be pounded into thin sheets (malleability) and drawn into wires (ductility) are both physical properties, as they can be observed without changing the composition of the substance.

Characteristic 7 - Conductivity

Being a good conductor of electricity is a physical property, as this attribute can be observed and measured without changing the substance.