The process of heating an ore in the presence of air to decompose it.
A substance composed of two or more elements that are chemically combined in definite proportions. A compound's makeup never changes: For example, a molecule of carbon dioxide always contains one atom of carbon and two atoms of oxygen.
The process in which a material forms a solid whose atoms, molecules, or ions form a regularly repeating pattern.
The process of purifying a liquid by evaporating it, then collecting and condensing the vapors.
A substance that cannot be broken down into simpler substances through chemical processes.
A combination of two or more substances in which each ingredient retains its own chemical identity. Unlike chemical compounds, the makeup of mixtures can vary: For example, air samples from a polluted city and a forest will have different compositions.
A process in which a substance changes directly from a solid phase to a gas phase without first becoming a liquid.
The conversion of an element into another element. Atoms of one element can be changed into atoms of another element. When the number of protons in an atom is changed, the atom is transmuted into an atom of another element.