IGCSE Glossary

Glossaries - GCSE chemistry

A substance with a pH value of less than 7 and which releases hydrogen ions (H⁺(aq)) when in water. 

Examples of acids are :HCl (hydrochloric acid), H₂SO₄ (Sulfuric acid), HNO₃ (Nitric acid)

Glossaries - GCSE chemistry

The least possible amount of energy required to start a reaction.

Glossaries - GCSE chemistry

Albert Einstein 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest physicists of all time. Einstein is known for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics. Relativity and quantum mechanics are together the two pillars of modern physics.

Glossaries - GCSE chemistry

Alexander Graham Bell (; born Alexander Bell, March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist, and engineer who is credited with inventing and patenting the first practical telephone.

Glossaries - GCSE chemistry

Glossaries - GCSE chemistry

Ammonia is a compound of nitrogen and hydrogen with the formula NH₃.

Ammonia is a colourless gas with a distinct pungent smell. It is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45 percent of world's food and fertilizers

Glossaries - GCSE chemistry

Glossaries - GCSE chemistry

the positive electrode in an electrolysis circuit

Glossaries - GCSE chemistry

An atmosphere is a layer of gas or layers of gases that envelope a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low.

Glossaries - GCSE chemistry

 

The smallest particle of an element which still retains all the properties of the element

 

Glossaries - GCSE chemistry

The number of protons in the nucleus of an atom. Also known as the proton number. 

Glossaries - GCSE chemistry

Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats

 

Glossaries - GCSE chemistry

A vessel or piece of apparatus that is used to determine energy changes involved in a chemical reaction. At it's simplest it could be a tin can. More sophisticated versions will be insulated to prevent heat loss.

Glossaries - GCSE chemistry

A substance that can be added to a reaction to increase the rate of reaction without being used up.

Glossaries - GCSE chemistry

the negative electrode in an electrolysis circuit