Term
|
Definition
| A very hard, brittle, heat-resistant substance that is used to grind the edges or rough surfaces of an object. boron carbide, diamond, and corundum are abrasives. |
|
|
Term
|
Definition
| Temperature measured on a scale that sets absolute zero as zero. In the SI system, the kelvin scale is used to measure absolute temperature. |
|
|
Term
|
Definition
optical density; extinction; decadic absorbance.
A measure of the amount of light absorbed by a sample. The absorbance (A) equals minus the base-10 log of the transmittance. |
|
|
Term
|
Definition
(CH3COOH, HC2H3O2) ethanoic acid; vinegar acid; methanecarboxylic acid.
A simple organic acid that gives vinegar its characteristic odor and flavor. Glacial acetic acid is pure acetic acid. |
|
|
Term
|
Definition
| 1. a compound which releases hydrogen ions (H+) in solution (Arrhenius). 2. a compound containing detachable hydrogen ions (Bronsted-Lowry). 3. a compound that can accept a pair of electrons from a base (Lewis).. |
|
|
Term
|
Definition
Compare with alkaline error.
A systematic error that occurs when glass pH electrodes are used in strongly acidic solutions. Glass electrodes give pH readings that are consistently too high in these solutions. |
|
|
Term
|
Definition
| Elements 89-102 are called actinides. Electrons added during the Aufbau construction of actinide atoms go into the 5f subshell. Actinides are unstable and undergo radioactive decay. The most common actinides on Earth are uranium and thorium. |
|
|
Term
|
Definition
(Ea)
The minimum energy required to convert reactants into products; the difference between the energies of the activated complex and the reactants. |
|
|
Term
|
Definition
| A pocket or crevice on an enzyme molecule that fits reactant molecules like a hand in a glove. The active site lowers the activation energy for reaction. |
|
|
Term
|
Definition
adiabatic process; isentropic process.
A process that neither absorbs nor releases energy into the surroundings. For example, a chemical reaction taking place in a closed thermos bottle can be considered adiabatic. Very fast processes can often be considered adiabatic with respect to heat exchange with the surroundings, because heat exchange is not instantaneous. |
|
|
Term
|
Definition
complex compound. Compare with hydrate.
An addition compound contains two or more simpler compounds that can be packed in a definite ratio into a crystal. A dot is used to separate the compounds in the formula. For example, ZnSO4ยท7 H2O is an addition compound of zinc sulfate and water. This represents a compound, and not a mixture, because there is a definite 1:7 ratio of zinc sulfate to water in the compound. Hydrates are a common type of addition compound. |
|
|
Term
|
Definition
(cohesion)
Attraction between different substances on either side of a phase boundary. |
|
|
Term
|
Definition
| A sample of precisely determined amount taken from a material. |
|
|
Term
|
Definition
(alkaline earth metal) alkali metal element.
The Group 1 elements, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr) react with cold water for form strongly alkaline hydroxide solutions, and are referred to as "alkali metals". Hydrogen is not considered an alkali metal, despite its position on some periodic tables. |
|
|
Term
|
Definition
(alkali metal)
The Group 2 elements, beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra) form alkaline oxides and hydroxides and are called "alkaline earth metals". |
|
|
Term
|
Definition
indirect titration.
Determining the concentration of an analyte by reacting it with a known number of moles of excess reagent. The excess reagent is then titrated with a second reagent. The concentration of the analyte in the original solution is then related to the amount of reagent consumed. |
|
|
Term
|
Definition
Balmer lines.
A series of lines in the emission spectrum of hydrogen that involve transitions to the n=2 state from states with n>2. |
|
|
Term
|
Definition
balanced.
A description of a chemical reaction that gives the chemical formulas of the reactants and the products of the reaction, with coefficients introduced so that the number of each type of atom and the total charge is unchanged by the reaction. For example, a balanced equation for the reaction of sodium metal (Na(s)) with chlorine gas (Cl2(g)) to form table salt (NaCl(s)) would be 2 Na(s) + Cl2(g) = 2 NaCl(s), NOT Na(s) + Cl2(g) = NaCl(s). |
|
|
