Chemistry Online Quiz

Hydrogen peroxide (H₂O₂) is water (H₂O) with an extra oxygen molecule. H₂O₂ contains a single oxygen-oxygen bond. When its oxygen-oxygen bond breaks, hydrogen peroxide decomposes into water and oxygen.

A limnic eruption (lake overturn) is a natural disaster in which dissolved carbon dioxide suddenly erupts from deep lake waters, forming a gas cloud capable of suffocating wildlife, livestock, and humans.

Natural radioactivity was discovered by Antoine Henri Becquerel. Henri Becquerel (1852-1908) was a French physicist who discovered radioactivity through his investigations of uranium and other substances. In 1903 he shared the Nobel Prize for Physics with Pierre and Marie Curie.

Earth's greenhouse gases trap heat in the atmosphere and warm the planet. The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapor (which all occur naturally), and fluorinated gases (which are synthetic).

Dry powder fire extinguishers contain sand and sodium bicarbonate. It sprays a very fine powder of sand and sodium bicarbonate (NaHCO₃, baking soda) or potassium bicarbonate (KHCO₃) or monoammonium phosphate ((NH₄)H₂PO₄).

Ozone consists of oxygen only. It is a triatomic, molecule, consisting of three oxygen atoms. The formula for ozone is O₃. Ozone in the upper atmosphere protects living organisms by preventing damaging ultraviolet light from reaching the Earth's surface.

Bronze is an alloy traditionally composed of copper and tin. Bronze is typically consists of approximately 88 percent copper and 12 percent tin.

Hydrogen peroxide is a chemical compound with the formula H₂O₂. It is used as an oxidizer, bleaching agent, and antiseptic. When an old oil painting is coated with hydrogen peroxide, it oxidised lead sulphide to form lead sulphate. The colour of the painting will retain it.

Gypsum is a mineral and is hydrated calcium sulphate in chemical form. It slows down the hydration process of cement once it is mixed with water. It is mainly used for preventing the rapid setting of cement.

Anthracite is the highest grade and best equality coal. It is a hard, very low content of volatile compact variety of coal that has a high luster. It has the highest carbon content (92.1% to 98%), the fewest impurities, and the highest calorific content.