Chemistry of the environment Water tests Anhydrous cobalt(II) chloride is blue. It turns pink when water is present. Anhydrous copper(II) sulfate is white. It turns blue when water is present. Purity A pure substance has a sharp melting point and boiling point. Impurities usually change and broaden these values. Distilled water is used to avoid dissolved impurities interfering with an experiment. Natural water Natural water may contain dissolved oxygen, metal compounds, plastics, sewage, microbes, nitrates, and phosphates. Dissolved oxygen supports aquatic life. ...

This study guide provides a comprehensive review of Electric Circuits and Electrical Safety based on the IGCSE Physics syllabus. It is structured to cover both Core and Supplement requirements.

Fundamental properties and behavior of electricity

Wave properties, light (reflection, refraction, dispersion, EM spectrum), and sound.

Kinetic particle model, states of matter, temperature, specific heat, and thermal transfer.