After discovering the atoms nucleus rutherford proposed an atomic model(electrons move around the nucleus like the planets move around the sun)This model couldnt explain the chemical properties of elements.
Bohr model(believed that rutherfords model needed improvment)He proposed that an electron is found only in specific circular paths or orbits around the nucleus.Each possible electron orbit has a fixed energy.(energy levels are the fixed energies an electron can have)
QUANTUM ENERGY=amount of energy required to move an electron from 1 energy level to another.
*The amount of energy an electron gains or loses in an atom is not always the
electron:One of the tiny particles that make up an atom. It has no charge and no mass.
neutron:one of the tiny particles that make up an atom. It has no charge and a mass of
1u.proton:one of the tiny particles taht make up an atom. It has a positive charge and a
mass of 1u.Nucleus:the core of the atom, that contains protons and neutrons. Therefore,
it has positive charge and mass.Compound:a substance formed by different types of
atoms.Atoms:tiny particles that make up matter and cannot be divided or destroyed.
Shell:it is the outside the nucleus and contains electrons . therefore , it has negative
charge and no mass.Element:a substance formed by the same types of atoms.
Pauli Exclusion Principle:
"Two electrons in the same atom can have the same quantum numbers are identical and therefore an orbital can not have more than two electrons.
The maximum number of electrons per level is 2 (n) 2
· ELECTRONIC CONFIGURATION OF THE ELEMENTS
SPECTRAL NOTATION: The schematic representation of the distribution of electrons in an atom according to Bohr's atomic model. The electrons tend to occupy the lowest energy orbital a. The figure below shows the order of filling orbitals.
Electron orbital MAXIMUM LEVEL BY LEVELElectron orbital MAXIMUM LEVEL BY LEVEL
EXAMPLE: Calcium spectral notation (Z = 20) is: 1s 22s 22p 63s 23p 64s 2
Known this order can ensure that the third electron to the 2s orbital anger.... Continue reading "General Chemistry" »
Solids have a definite shape and a definite volume. they are not motionless.
Types of Solids: Crystalline Solids and Amorphous Solids.
Crystalline regular and repeating, definite melting point. Amorphous are not repeating, softer when heated, no definite melting point.
Liquids have no definite shape, but a definite volume.
Viscosity Of Liquids: High viscosity liquids flow slowly, and low viscosity liquids flow quicker.
Gases: Move at high speed in all directions, can fill all space containers, no definite shape, nor volume.
State of Matter & Temperature: temperature can determine if its solid, liquid or gas.
Thermal Energy: particles a substance has because molecular motion, flow from warmer substance to cooler substance.
Changes in State: Melting,... Continue reading "Solids, Liquids, And Gases" »
- 2.9 moles
- Fe(OH)3 + NH4Cl
- Gas, Water, or precipitate are produced
- 815 ml
- 0.15 M
- Crystals attach to the object
- 3.9 ml
- 8681 g
- Two different compounds
- 14 moles
- Na+ and NO3
- 60 L
- Boyle’s Law
- Double displacement
- Single Replacement
- H+ (aq) + HCO3-(aq) H2O(l) + CO2(g)
- Not fixed
- When the total increase of oxidation numbers equals the total decrease in oxidation numbers
- 1 x 10-9
- q = c x m x t
- 1.90 mol
- 10.6 mol
- 1.53 L
- 32 x 103 L
- Nonpolar covalent
- .0987 mol
- Brownian Motion
- 40 mol
- 144 ml
- 67.2 g
- Reducing agent
- 38.4 atm
... Continue reading "Chemistry Topic 1" »
FIRST ATOMIC MODELS: **** The idea emerged in the d atom 450 BC with Democritus. ** On 1 atomic model was the "d Dalton atomic model" **** DALTON: exposed atomic-molecular theory of matter d q d possible to explain the behavioral differences between simple and compound substances *** The material consisted q x atoms were indivisible particles iondestructibles (so-called simple substances, q constitute a single element) *** The compounds are formed atoms d d x combinations different chemical elements (forming "compound atoms" are molecules today q) ** * Atoms are the same element d = mass properties and different d *** elemtos Atoms have different mass and chemical properties. *** In the chemical reactions mass always remains cte d *** Act
pure substance: is a phase of uniform composition and unchanging can not be decomposed into other substances of different classes by physical methods.
elements: they are pure substances that can not be decomposed into simpler ones through normal chemical processes.
compounds: they are pure substances made up of two or more elements, which can be decomposed by chemical methods on the elements of which are constituted. A compound always has the same elements and the same proportions regardless of the process followed.
Blended is an aggregation of different substances without causing any chemical reaction between them and therefore may be separated by physical methods.
the titrant is available in a burette.
Nalito available along the cone l volumetric flask indicator him (Erlenmeyer)
Volumetria straightforward: using the conventional procedure
Volumetria reverse (back-) is added in known excess titrant and titrate the excess back.
Ekivalencia Point: The point at which the amount of agent valorantey valued substance, estekiometricamente match.
Final point: experimental point it is detected ekivalencia point.
Indicator: substance or technique to visualize or detect the endpoint.
IF BOTH ITEMS MUST AGREE NOT PLACE ON "THE VOLUMETRIC ERROR"
1 .- Acid-base titrations (protolithic)
2. precipitation titration
3. Redox titrations
4.... Continue reading "Volumetric technique" »