Dalton |
Atomic mass is not measured in pounds or grams. Scientists used something called Daltons. One Dalton is equal to one-twelfth the mass of a carbon atom. Scientists also call a Dalton an Atomic Mass Unit.
More Information: Atoms |
Definite Proportions |
This is a concept that explains how formulas of similar compounds are identical no matter where you are in the universe. Sodium chloride will always be made of one sodium and one chloride atom. Water will always be made of one oxygen and two hydrogen atoms.
More Information: Compounds |
Deliquescence |
This term describes the characteristic of some solids to absorb water and eventually dissolve. Sodium hydroxide is deliquescent. You may be familiar with little packets of powder used in packing materials. The chemicals inside those packs absorb any moisture from the air in the box and keep the contents dry.
More Information: Solids |
Dendritic Habit |
A dendritic habit describes the shape of a large group of crystals that looks like the branching of veins or a plant.
More Information: Crystals |
Desiccant |
A desiccant goes through a process of deliquescence to dry an area or volume of air. Desiccants are often found in small packs when humidity needs to be decreased.
More Information: Gases |
Diffusion |
Diffusion is a process that happens when a substance moves from an area of higher concentration to an area of lower concentration.
More Information: Gases |
Dilute Solution |
A solution (liquid mixture) that has a small amount of solute dissolved. As you add more water to a sugar solution the solution, becomes more and more dilute.
More Information: Solutions |
Dilution |
Dilution occurs when a solution with a known concentration (standard solution) has more solvent added. As the solvent is added, the molarity may change, but the number of equivalents will not.
More Information: Solutions |
Disaccharide |
A carbohydrate that is made up of two mono-saccharides.
More Information: Carbohydrates |
Distillation |
Distillation is a process in which one substance is boiled away from another and then collected. It is a process that purifies mixtures and solutions. Scientists often use lab equipment such as a distillation flask and a condenser. The boiled off vapor is cooled and "condensed".
More Information: Solutions |
Distilled Water |
Distilled water is pure water. Tap water contains all sorts of impurities. When all of those impurities are removed, you have distilled water. You can get it by boiling water and collecting the steam.
More Information: Liquids |
Disulfide Bond |
Covalent disulfide bonds form during the tertiary structure of protein synthesis. It involves two sulfur atoms bonded to cysteine amino acids in the polypeptide chains.
More Information: Proteins |
Dodecahedral Crystal |
A crystal that has twelve sides. A twelve-sided object is called a dodecahedron.
More Information: Solids |
Double Replacement |
A chemical reaction where two compounds are mixed and they exchange parts of their compounds with each other. Think about the mixing of an acid and a base. You start with an acid and base and finish with water and a salt.
More Information: Compounds |
Dubnium |
Symbol:"Db" Atomic Number:"105" Atomic Mass: (262)amu Dubnium is one of several postactinide elements. Scientists have created these in labs and may have only found a few atoms of the element. You will not find these in use anywhere.
More Information: Transition Metals |
Dysprosium |
Symbol:"Dy" Atomic Number:"66" Atomic Mass: 162.50amu. Dysprosium is one of the elements in the lanthanide series of inner transition elements. It may also be classified as a rare earth element. You may find this element in lasers, many alloys, and even nuclear reactors.
More Information: Lanthanide Series |