Question

Read the following description of the element zinc, and indicate which are physical properties and which are chemical properties. Zinc is a silver-gray- colored metal that melts at \(420^{\circ} \mathrm{C}\). When zinc granules are added to dilute sulfuric acid, hydrogen is given off and the metal dissolves. Zinc has a hardness on the Mohs scale of \(2.5\) and a density of \(7.13 \mathrm{~g} / \mathrm{cm}^{3}\) at \(25^{\circ} \mathrm{C}\). It reacts slowly with oxygen gas at elevated temperatures to form zinc oxide, \(\mathrm{ZnO}\).

Short answer

Physical properties of zinc include its silver-gray color, melting point of \(420 ^{\circ} \mathrm{C}\), hardness on the Mohs scale of \(2.5\), and density of \(7.13 \mathrm{~g} / \mathrm{cm}^{3}\) at \(25^{\circ} \mathrm{C}\). Chemical properties include its reaction with dilute sulfuric acid, producing hydrogen and dissolving the metal, and its reaction with oxygen gas at elevated temperatures to form zinc oxide, ZnO.

Step-by-step solution

1. Define Physical and Chemical Properties

Physical properties are characteristics of a substance that can be observed without changing its chemical composition. They include properties such as color, density, melting point, and hardness. Chemical properties are characteristics of a substance that describe its ability to undergo chemical changes and reactions. Examples of chemical properties include reactivity and flammability.

2. Identify Physical Properties

In the description of zinc given in the exercise, we can identify the following physical properties: - Silver-gray color - Melting point of \(420 ^{\circ} \mathrm{C}\) - Hardness on the Mohs scale of \(2.5\) - Density of \(7.13 \mathrm{~g} / \mathrm{cm}^{3}\) at \(25^{\circ} \mathrm{C}\) These properties are identified as physical because they can be observed without changing the substance's chemical composition.

3. Identify Chemical Properties

In the description of zinc given in the exercise, we can identify the following chemical properties: - When zinc granules are added to dilute sulfuric acid, hydrogen is given off, and the metal dissolves. - Zinc reacts slowly with oxygen gas at elevated temperatures to form zinc oxide, ZnO. These properties are identified as chemical properties because they describe zinc's ability to undergo chemical reactions and changes.