Chemistry

Every moment of every day, chemistry plays a part in all we experience. This branch of the Helium network humbly attempts to illuminate the vast array of chemical knowledge, making it accessible to all. Let our site inform, inspire, and awe you with chemical wonders.
How to tell if a substance is an acid or a base
By: Effie Moore Salem
The most common way to tell if a liquid is an acid or a base is to submit it to a litmus test. A drop of a liquid acid substance on a test sheet of litmus paper will turn red; if the liquid is base...
What are Ven der Waals forces?
By: Helena Whyte
Johannes van der Waals developed a model to explain the behavior of liquids and solids that reflected the size of the atoms or molecules and the strength of the forces between these atoms or molecules. The weak intermolecular forces in liquids and solids are called...
How isotopes are used
By: Effie Moore Salem
Isotopes are used in medicine, and in other areas of technology. Isotopes are atoms of an element that have a different number of neutrons. In these atoms, the smallest particle of matter, neutrons and protons reside in the nucleus of an atom. Stability in atoms...
Understanding the periodic table of elements
By: Effie Moore Salem
The periodic table of elements at first glance resembles a scrabble board in that colored squares of information are lined up horizontally and vertically. Within these blocks of information we learn the symbol of elements, the atomic weight, the date the element was discovered, and...
The basis for Dalton's atomic theory
By: John JS Smith
Though we credit Dalton with the invention of the atomic theory, he was not the one who formulated the three principles stated in the theory. The atomic theory has three main ideas. They are as follows. 1. All matter is made up of atoms. 2...
By: John Traveler
About a hundred years ago, Albert Einstein posited a brilliant deduction based on his theory of special relativity. One facet of Einstein's theory suggested that matter and energy were related and he developed his famous E=mc2 formula to demonstrate this relationship. He further posited that...
The history of the periodic table of elements
By: Helena Whyte
The first person to try to organize the chemical elements into patterns was Johann Dobereiner. He grouped families of elements into triads in order of atomic mass in 1828. Elements were grouped into families because of the similarities in reaction types and in the formulas...
By: Helena Whyte
Atoms with the same number of protons but different number of neutrons are called isotopes. Each element found in nature is a mixture of isotopes. The most common atomic mass for carbon is twelve: six protons and six neutrons. Carbon-thirteen is the rarest isotope of...
What are Ven der Waals forces?
By: Brian Dodson
Bonds formed between atoms and molecules are, quite literally, what holds our world together. Without such intermolecular bonding, we would be surrounded by a formless jumble of swirling gases – save for the fact that we, too, would also be reduced to our component parts...
Historic changes to the periodic table of elements
By: Luke Buffington
The Periodic Table of the Elements is a display of the 118 known chemical elements. It is organized according to the repeating properties of the elements in each group on the table, hence the name periodic. Classifying these elements has been an ongoing journey for...

 

1 78 79 80 81 82 130
CHOOSE YOUR SCIENCES 360 TOPIC: