The Martian atmosphere consists of approximately 96% carbon dioxide, 1.9% argon, 1.9% nitrogen, and traces of free oxygen, carbon monoxide, water and methane.

The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as Dipole-dipole interaction, the London dispersion force and hydrogen bonding.

Copper has higher reduction potential (more positive) than hydrogen and therefore does not react with HCl acid.

A metamorphic rock is a result of a transformation of a pre-existing rock. Obsidian is a naturally occurring volcanic glass formed when felsic lava extruded from a volcano cools rapidly with minimal crystal growth.

The most abundant elements in the Earth's crust are oxygen (46.6%) and silicon (27.7%). Minerals which combine these two elements are called silicates.

Earth is the densest planet in our Solar System, with an average density of 5.51 grams per cubic centimeter.

The Earth's inner core is believed to be primarily a solid ball with a radius of about 1220 kilometers. It is composed of an iron-nickel alloy and some light elements.

Fossil fuels are hydrocarbons, primarily coal, fuel oil or natural gas, formed from the remains of dead plants and animals. Solar power is obtained by harnessing the energy of the sun's rays.

A "pure" compound simply indicates that a substance includes two or more elements in a specific ratio, which never varies. The chemical structure of glucose is always C6H12O6.

Igneous rock is formed through the cooling and solidification of magma or lava.