Chemistry Definitions
1. Acid:
Proton donor.
2. Activation energy:
Minimum energy that colliding particles must have to react.
3. Alloy:
Mixture of a metal with other elements including:
Brass: Copper and zinc
Stainless steel: Iron, nickel, chromium and carbon.
4. Anhydrous substance:
Substance containing no water.
5. Atom:
Central nucleus containing neutrons and protons surrounded by electrons in
shells.
6. Base:
Proton acceptor.
7. Catalyst:
Substance that speeds the rate of chemical reaction without being itself changed.
8. Closed system:
No substance can enter or leave during the reaction.
9. Covalent bond:
Formed when a pair of electrons is shared between two atoms leading to
noble gas electronic configuration.
10. Diatomic:
Consists of 2 atoms. Ex. (Halogens).
11. Diffusion:
Movement of particles from high concentration area to low concentration area.
12. Electrolysis:
Breaking down of ionic compounds when molten or aqueous by the passage
of electricity.
13. Electrolyte:
Ionic compound molten or aqueous substance that undergoes electrolysis and can coduct
electricity .
14. Empirical formula:
Simplest whole number ratio of the different atoms or ions in a compound.
15.Endothermic reactions:
Takes in thermal energy from the surroundings leading to a decrease in the
temp. of the surrounding.
16. Enthalpy change:
Transfer of thermal energy during a reaction.
17. Excess reactant:
Reactant which remains when reaction stop as it find nothing to react with
when the limiting reactant is consumed.
18.Exothermic reactions:
release thermal energy to the surrounding leading to an increase in the
temp. of the surroundings.
19. Fertilizers:
Substance added to the soil to promote the growth of the plants.
20. Galvanization:
Coating the iron with a layer of zinc. (EXTRA INFO: can be done by
electroplating.
Zinc is more reactive than iron so loses electrons instead of iron so it will
oxidize and react with oxygen).
21. Group (VIII):
Noble gases have a full outer shell and oxidation number equal zero, they
don’t lose or gain.
22.Heterogenous catalyst :
Catalyst and reactants are indifferent phase.
23. Homogenous catalyst:
The catalyst and the reactants are in the same phase.
24. Homologous series:
family of organic compounds with similar chemical properties due to the
presence of the same functional group.
25. Hydrated substance:
Substance chemically combined with water.
26. Hydrocarbons:
Compounds containing carbon and hydrogen only.
27. Hydrogen Fuel Cell:
the reaction of Hydrogen and oxygen to produce electricity with water
as only chemical product.
28. Indicator:
Substance its color change with the change of pH
29. Ionic bond:
Strong electrostatic attraction between oppositely charged ions.
30. Ionic lattice:
Regular arrangement of oppositely charged ions/ alternating positive and
negative ions.
31. Isotopes:
Atoms of the same element, have the same proton number but different
number of neutrons.
32. Limiting reactant:
The reactant that limits amount of products and the reaction will stop when all
limiting reactants are consumed.
33. Mass number/Nucleon number:
Total number of neutrons and protons in the nucleus of an atom.
34. Metallic bond:
Electrostatic attraction between the positive ions and a sea of delocalized electrons.
MENTIONING FREE MOVING ELECTRONS IS CANCELLED.
35.Microplastics or microbeds:
Tiny pieces of plastic that are found in water and it can be swallowed by
aquatic animals.
36. Mole one substance:
substance is it’s Mr expressed in grams.
37. Mole:
unit of amount of substance and that one mole contains 6.02 x 10 23particles
Avogadro constant.
38. Molecular formula:
Number and type of different atoms in one molecule.
39. Monoatomic:
consists of one atom only. Ex. Noble gas
40. Oxidation:
Loss electrons and increase the oxidation no.
41. Oxidizing agent:
Substance that oxidizes another substance and is itself reduced.
42. Periodic table:
Arrangement of elements in periods and groups and in order of increasing
atomic number/ proton number.
43. Precipitate:
Tiny particles of solid that don’t dissolve and makes the solution cloudy.
44. Precipitation:
Formation of insoluble salt when 2 soluble salts are mixed together.
45. Proton number/Atomic number:
Number of protons in the nucleus of an atom.
46. Reducing agent:
Substance that reduces another substance and itself oxidized.
47. Reduction:
Gain electrons and decrease the oxidation no.
48. Relative atomic mass:
Average mass of the isotopes of an element compared to 1/12 th of the mass
of an atom of 12C.
49. Relative molecular mass Mr:
Sum of the relative atomic masses of all elements in a compound (covalent)
formula mass, Mr will be used for ionic compounds.
50. Roman numeral number:
Indicate the oxidation number.
51. Rust:
Red brown flaky solid formed on the iron. Chemical name is hydrated iron (III) oxide.
52. Saturated compounds:
All carbon-carbon bonds are single.
53. Saturated solution:
Solution in which no more solute will dissolve in a solvent at a certain
temperature.
54. Strong acid:
Fully ionized in solution giving high concentration of hydrogen ions H+.
55. Strong Base:
Completely ionized in a solution giving high concentration of OH56. Triatomic:
Consists of 3 atoms.
57. Unsaturated compound:
One or more carbon-carbon bonds are double or triple bonds.
not all carbon - carbon bonds are single.
58. Water of crystallization:
Water molecules present in hydrated crystals.
59. Weak acid:
Partially ionized in solution giving low concentration of H+.
60. Weak Base:
Partially ionized in a solution giving low concentration of OH-