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GenChem 2 - Coggle Diagram

- - - - Miscible solution: is the two or more liquids that are soluble in each other.
      - Immiscible solution: is the two or more liquids that are not soluble in each other.
      - In order to get a homogenous mixture, the solutes and solvent must applies the "like dissolves like" rules. It is when the solutes and the solvent have the same in their polarity.
  - - - The corner of a crystal solids are tend to be easily dislodge due to its has fewer intermolecular bonds.
        
        The process of dislodging a molecules involves an energy.
    - - Dissolving solids in liquids occurs in two steps.
        
        Lattice energy: the energy needed to dislodge the lattice structure of solid.
        
        Solvation energy: the energy released for binding of the gaseous particles with solvent molecules.
      - Dissolving liquids in liquids occurs in three steps.
        
        Solute energy: the energy needed for expanding the solute liquid.
        
        Solvent energy: the energy needed for expanding the solvent liquid.
        
        Solvation energy: the energy released for binding the expanded solute liquids and solvent liquids.
    - - The overall value of the heat of solution = 0.
    - - Solubility of a gas increases in a high pressure.
        
        Applies Henry's Law: where the concentration of gas in liquid at any given temperature is directly proportional to partial pressure of gas over solution.
        
        Formula: Cgas = kHPgas
        
        When Henry's constant is unknown: C1 x P2 = C2 x P1.
        
        When a measurement is done under several different temperature condition, use temperature-independent concentration unit.
        
        Percent Concentrations: mass of solute/mass of solvent x 100%
        
        Molal concentration: mol of solute/kg of solvent
        
        Mole fraction: mol A/total moles of all component
  - - - Does not depend on the type of the chemical.
    - - Vapor pressure depression (Raoult’s Law)
        
        Formula: Psolution = Xsolvent x Posolvent
        
        Low vapor pressure = attractions between molecules in the mixture are stronger than the pure solvent.
        
        High vapor pressure = attractions between molecules in the mixture are weaker than the pure solvent.
        
        At freezing temperature, the solvent molecules are slows down and form a strong intermolecular attraction resulting in a lower (Tf) freezing point.
      - Boiling point elevation
        
        A nonvolatile solute will decrease the vapor pressure, then the rate of evaporation is also lower. In order for the nonvolatile solute to vapor, it needs a higher temperature and results in higher Tb (boiling point).
        
        Formula: DTb = Kb x m
      - Freezing point elevation
        
        At freezing temperature, the solvent molecules are slows down and form a strong intermolecular attraction resulting in a lower (Tf) freezing point.
        
        Formula: DTf = Kf x m
      - Osmotic pressure
        
        Osmosis is the movement of water molecules from a low concentrated region to a high concentrated region through a osmotic membrane (semipermeable membrane) to form an equilibrium.
        
        Formula
        
        Π = MRT
        
        ΠV = nMRT
- - - - The solubility of the solute in solvent increase as the temperature increases. For gases, the solubility decrease when the temperature is increased.
    - - Molecules that have the similar attractive forces are easy to dissolve and make a solution. Polar substances are more likely to dissolve in polar solvent. Non polar substances dissolve in non polar substances.
    - - When a solution contains common ion with an insoluble is added to that salt, the solubility decreases.
    - - The alteration in pH can increase or decrease the solubility, depending on the properties of the substances involved. The solubility of the base increases when the pH is increased, while the solubility of acid increase when the pH is increased.
    - - Some compounds don't completely dissolve in water. The formation of ion complexes can increase the solubility of these compounds as the complex ions are soluble.
    - - The solubility of the gas molecules tend to be dissolved when the pressure is increased. More gas molecules dissolve in higher pressure.
  - - - In a saturated solution, the dynamic equilibrium is established between undissolved solids and the ionic species in the solution. It represents the balanced state where the forwards and reverse reaction proceed at the equal rate and the concentration remains constant.
    - - Insoluble salt does not mean totally insoluble in solvent, small amount of insoluble salt can still be dissolved in water a
        Ksp is a measurement of how much the slightly insoluble salt dissolve in water.
        
        The higher Ksp value indicates that the substances is more soluble. Ksp can be determined by calculating Molar solubility, the number of moles of salt dissolved in one liter solvent.
        
        The precipitation can be predict by observing the Q (reaction quotient) value. The Q value can be determined as the same way as Ksp.
        
        Q=Ksp, there is no precipitation
        
        Q>Ksp, the solute precipitates
        
        Q<Ksp, there is no precipitation
      - Selective Precipitation
        
        Due to different solubilities, the solvent will bind with the solute with high solubility first before bind with the other. Once no solvent available to produce solution, the lower solubility solute will precipitate
  - - - A solution that can dissolve more solute because the concentration of the solute is less than the maximum solubility.
    - - A solution that contains the maximum amount of solute that can dissolve. The solute concentration is equal to the solubility of the solute dissolve in a solution. The addition of more solute leads to the precipitation.
    - - A solution that contains more solute than the solute solubility at specific temperature. By heating the solution, the solute can be dissolved. But when the solution is cooled down, addition of more solute will caused the solution to crystalized.
- - - - 𝒙𝑨 + 𝒚𝑩 ⇌ 𝒘𝑪 + 𝒛D
      - Kc = the molar concentrations of products divided by the molar concentrations of reactants
        
        When the direction of an equation is reversed, the new equilibrium constant is the reciprocal of the original
        
        K = 1 = equilibrium lies midway between reactants and products
        
        K < 1 = equilibrium lies on the left towards the reactants
        
        K > 1 = equilibrium lies on the right towards the product
    - - A condition where the concentration of products and reactant do not change because of the two opposing reaction has the same reaction rate.
        
        Reversible
        
        proceed in both forward and reverse directions.
        
        When the rate of the decomposing is equal to the rate of the formation reaction, it reached dynamic equilibrium.
        
        Concentrations of chemical species do not change once equilibrium is established.
        
        A → B (forward reaction)
        
        A ← B (reverse reaction)
      - Equilibrium Law for Homogenous Reactions
        
        Reactions involving only one phase are called Homogenous Reactions
      - Equilibrium Law for Heterogenous Reactions
        
        For any pure liquid or solid, the ratio of the amount of substance to the volume of the substance is constant.
        
        in heterogeneous equilibrium exclude pure solids or pure liquids in the equilibrium law and write as a value of 1
      - Reaction quotient, Qc used to predict equilibrium shift
        
        Qc < Kc, a net forward reaction (to product)
        
        Qc > Kc, a net reverse reaction (to reactant)
        
        Qc = Kc, equilibrium (no net reaction)
  - - - Factors that influence equilibrium:
        
        Temperature
        
        Exothermic
        
        Reaction that produces heat
        
        ΔH is negative.
        
        Endothermic
        
        Reaction that absorbs heat
        
        ΔH is positive
        
        Decreasing the temperature
        
        Shifts a reaction in a direction that require to release heat (exothermic)
        
        Increasing the temperature
        
        Shifts a reaction in a direction that require to absorb heat (endothermic)
        
        Partial pressure
        
        Decreased volume = Increased pressure
        
        Increased pressure favor direction with less moles
        
        Concentration
        
        Addition of a substance will proceed the reaction to remove some of it.
        
        Removal of a substance will proceed the reaction to replace it
        
        Catalyst
        
        A substance that affects the speeds of chemical reactions without actually being used up.
        
        They do not affect the equilibrium constant because they only bring the system to equilibrium faster.
- - - - Van der Waals Forces: attraction between partial positive and negative electrical charges molecules tha t are very close to each other.
        
        Dipole : the uneven distribution of electrons in a molecule due to the varying electronegativity in each atom, resulting in two poles with opposite charges (example: HCl)
        
        Hydrogen bonding
        
        Types of substances that exhibit attraction: Occurs when molecules contain N-H, F-H, and O-H bonds
        
        Strength relative to a covalent bond: 5-10%
        
        Ion-dipole attractions
        
        Types of substances that exhibit attraction: occur when ions interact with polar molecules
        
        Strength relative to a covalent bond: About 10%; depends on ion charge and polarity of molecule.
        
        Dipole-dipole attractions
        
        Types of substances that exhibit attraction: Occur between molecules that have permanent dipoles (polar molecules)
        
        Strength relative to a covalent bond: 1-5%
        
        Ion-induced dipole attractions
        
        Types of substances that exhibit attraction: Occur when an ion creates a dipole in a neighboring particle, which may be a molecule or another ion
        
        Strength relative to a covalent bond: Variable, depending on the charge on the ion and the polarizability of its neighbor.
        
        London dispersion forces
        
        Types of substances that exhibit attraction: all atoms, molecules, and ions experience these kinds of attractions. They are present in all substances
        
        Strength relative to a covalent bond: Depends on sizes and shapes of molecules. For large molecules, the cumulative effect of many weak attractions can lead to a large net attraction.
  - - - Gas
        
        Retain volume, Confor to shape of the container, able to flow , and nearly incompressible
      - Liquid
        
        Retain volume, retain shape, virtually incompressible, often have crystalline shape
      - Solid
        
        Easily compressed, expand spontaneously to fill container
    - - Tightness of packing
        
        Compressibility
        
        A measure of ability of a substrate to be forced into a smaller volume
        
        Gases compress easily-> molecules are far apart
        
        Liquids and solid are incompressible -> molecules are packed together
        
        Diffusion
        
        Ability of molecules to move from one position to another
        
        gas: diffusion occurs quite rapidly because the gap between molecules are large
        
        liquid: diffusion is slower because the molecules in liquid are packed causing many collisions when molecule move around
        
        solid: diffusion is almost nonexistent at room temperature because the particles are tightly held in place.
      - Strength of intermolecular attractions
        
        Volume and shape retention
        
        the ability of substances to maintain its shape and volume against external forces
        
        Gas: the attraction forces between molecules are so weak -> gas can change its shape and volume depend on its container
        
        Liquid: intermolecular forces are stronger than in gases-> allows liquid to maintain volume but not a fixed shape. Therefore, a liquid will follow to the shape of its container due to the mobility of its molecules while retaining its volume.
        
        Solid: the attraction forces are even stronger that the molecules are tightly packed and placed -> makes the particles of solid inflexible and retain its volume and shape.
        
        Surface tension
        
        The tendency of liquid to seek a shape that yields the minimum surface area
        
        caused by intermolecular forces between liquid molecules
        
        molecule at the surface -> higher potential energy than a molecule in the bulk. For a liquid, reducing its surface area -> lowers its potential energy
        
        potential energy decrease -> stable system
        
        smallest surface area possible: spherical shape
        
        Wetting of surface
        
        The spreading of a liquid across a surface to form a thin film
        
        The intermolecular attractions between the liquid and the surface must be about the same strength as the attractions within the liquid itself.
        
        When the glass is coated by a film of oil or gases -> interact by London forces -> very weak compare to H bonds -> wetting not occur
        
        Viscosity
        
        properties of liquid to resist change in form (example: syrup)
        
        factors that influenced viscocity
        
        Intermolecular attraction
        
        Molecular shape and size
        
        Temperature
  - - - Dynamic Equilibrium in Evaporation
        
        Before system reaches equilibrium
        
        rate of evaporation >> rate of condensation
        
        System at equilibrium
        
        Rate of evaporation = rate of condensation
        
        The number of molecules in the vapor will remain constant = dynamic equilibrium
        
        Rate of evaporation depends on factors:
        
        Surface area of the liquid
        
        surface area increased -> more molecules are able to escape (liquid evaporates more quickly)
        
        Temperature
        
        temperature increased -> kinetic energy increases -> rate of evaporation increases
        
        Strengths of intermolecular attractions
        
        stronger intermolecular attractive forces -> slower rate of evaporation at given temp.
      - Dynamic Equilibrium in Melting
        
        Melting point: the temp. at which the solid begins to change into liquid as heat added
      - Dynamic equilibrium in sublimation
        
        molecules evaporate from solid at the same rate as molecules condense from vapor
      - Formula:
        
        q when no phase change = m.s. delta t
        
        q when there is phase change = n. delta H
        
        q final = total of q
    - - The pressure caused by molecules that enter the vapor state when a liquid evaporates
        
        the concentration of molecules in the vapor remains constant and the vapor exerts a constant pressure (equilibrium vapor pressure)
      - Factors affecting the equilibrium vapor pressure
        
        temperature
        
        The temperature increases -> vapor pressure increases
        
        Intermolecular forces
        
        stronger intermolecular forces -> lower vapor pressure
      - Factors that are not effecting vapor pressure
        
        surface area, volume of liquid, volume of container
    - - The temperature at which the vapor pressure of the liquid equal to atmospheric pressure
        
        strong intermolecular attractions -> causing low vapor pressure -> results in higher boiling point
    - - "When a dynamic equilibrium in a system is upset by a disturbance, the system responds in a direction that tends to counteract the disturbance and, if possible, restore the equilibrium."
        
        heat + liquid ⇌ vapor
  - - - the symmetrical features of a repeating structure : lattice
        
        the repeating unit of the lattice: unit cell
        
        Types of crystal
        
        Molecular
        
        Particles occupying lattice sites: Atoms or molecules
        
        Types of attractive force: Dipole-dipole attractions, London forces, hydrogen bonds
        
        Examples: HCl, SO2, N2, Ar, CH4, H2O
        
        Typical properties: Soft, low melting points, nonconductors of electricity in both solid and liquid states
        
        Covalent
        
        Particles occupying lattice sites: Atoms
        
        Types of attractive force: Covalent bonds between atoms
        
        Examples: Diamond, SiC, SiO2
        
        Typical properties: Very hard, very high melting points, nonconductors of electicity
        
        Ionic
        
        Particles occupying lattice sites: Positive and negative ions
        
        types of attractive force: Attractions between ions of opposite charge
        
        Examples: NaCl, CaCl2, NaNO3
        
        Typical Properties: Relatively hard, brittle, high melting points, nonconductors of electricity as solids, but conduct when melted
        
        Metallic
        
        Particles occupying lattice sites: Positive ions
        
        Types of attractive force: Attractions between positive ions and an electron cloud that extends throughout the crystal
        
        Examples: Cu, Ag, Fe, Na, Hg
        
        Typical Properties: Range from very hard to very soft, melting points range from high to low, conduct electricity in both solid and liquid states, have characteristic luster
- - - - 1. Chemical nature of reactant
        Bonds break and new bonds form in reactions
        Fundamental differences among reaction rates depends on the reactants nature (atoms, molecules,
        or ions) tendencies to undergo changes.
      - 2. Ability of the reactants to meet
        The area of contact between the phases determining the rate of the reaction.
        If all of the reactants in the same phase = homogeneous reactions
        All the reactants are present in different phases = heterogeneous reaction
      - 3. Concentrations of the Reactants
        Higher concentrations of reactants increase the reaction rate.
      - 4. Temperature of the system
        Higher Temperature increase the reaction rate.
      - 5. Presents of catalyst
        Catalysts are substances that increase the rates of chemical reactions
        without being used up.
      - Rate Laws
        
        An exponent in a rate law is called the order of the reaction with respect to the corresponding reactant.
        The order of a reaction with respect to a given reactant determines how the reaction rate is affected by
        the concentration of that reactant.
        Most common order reaction:zero-order, first-order, and second-order reaction.
        A higher-order reaction means that the rate is more responsive to changes in reactant concentration, but it
        does not necessarily mean the reaction is faster overall.
  - - - Arrhenius Equation Logarithmic Form
        
        If the activation energy and rate constant at particular temperature is known, rate constant at different temperature can be calculated using
- - - - formations
        
        sp Hybrid orbitals are formed when mixing S and p orbitals, forming two 'lobes'
        
        sp2 hybrid orbitals are formed when one s orbital and two p orbitals collide, forms three hybrid sp2 orbitals.
        
        sp3 hybrid orbitals are formed when one s orbital and three p orbitals combine and forms four sp3, shaped like a tetrahedron
      - ways to overlap
        
        sigma bond: bond generated because of the overlapping of orbitals in head-to-head ways, creating strong affinity
        
        Pi bond: bond generated because of the overlapping of orbitals in side-to-side ways, creating less affinity
        
        Sigma (σ) bond has a stronger characteristic than Pi (π) bond
        
        π bond tend to break up first before σ bond
  - - - Each with different shape, and are located at varying distances from nucleus (s,p,d,f)
        
        S orbitals contain a maximum of 2 electrons
        
        P orbitals can hold up to 6 electrons
        
        D orbitals can hold 10 electrons
        
        F orbitals hold 14 electrons
  - - - Bond order can determine if a homonuclear diatomic exist or not, 0 = does not exist !
      - Bond order could be found by filling electron in the bonding molecular orbital first and then subtracting it with the nonbonding electron.
        
        MO diagram for H2.
        
        In p orbitals can overlap by two modes, which correspond to two ways their wave functions combine
        
        Side-to-side combination gives a pair of pi (π) MOs, π2p and π*2p.
        
        End-to-end combination gives a pair of σ MOs, σ and σ* .
        
        σ 2 p < π 2 p < π 2 p < σ 2 p
        
        In 2p, the lower energy order is filled first, and then filled as the same as previous way to found bonding order.