Question

Identify the chemical and physical changes discussed in the following 2 paragraphs by circling them and writing either a "C" for chemical and "P" for physical changes.

Sodium is silver-white and soft. It can be cut with an ordinary kitchen knife and is a good conductor of electricity. It can be [P]
prepared by passing electricity through molten sodium chloride.

The metal boils at 883°C and gives off a violet-colored vapor. Sodium metal tarnishes rapidly in air. It burns when heated in air or in an atmosphere of bromine vapor. [C]

Bromine is a reddish-brown liquid at room temperature. It vaporizes readily to form a red vapor. It boils at 58.8°C and freezes at -7.2°C. The density of the vapor is 7.59 g/L and the density of the liquid is 3.12 g/mL at 20°C. Bromine can be prepared by bubbling chlorine gas through solutions that contain bromine compounds. [C]
Sodium metal will burn in an atmosphere of bromine vapor. [C]

Answer 1

The chemical changes discussed in the paragraphs are the preparation of sodium and bromine, and the burning of sodium in bromine vapor.

Step-by-step explanation:

The chemical and physical changes discussed in the paragraphs are:

Sodium is silver-white and soft. It can be cut with an ordinary kitchen knife and is a good conductor of electricity. It can be prepared by passing electricity through molten sodium chloride. The metal boils at 883°C and gives off a violet-colored vapor. Sodium metal tarnishes rapidly in air. It burns when heated in air or in an atmosphere of bromine vapor. - Chemical change (C)

Bromine is a reddish-brown liquid at room temperature. It vaporizes readily to form a red vapor. It boils at 58.8°C and freezes at -7.2°C. The density of the vapor is 7.59 g/L and the density of the liquid is 3.12 g/mL at 20°C. Bromine can be prepared by bubbling chlorine gas through solutions that contain bromine compounds. - Chemical change (C)

Sodium metal will burn in an atmosphere of bromine vapor. - Chemical change (C)