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Chemistry (Structure of an Atom (Properties of an Atom (Atomic mass (This…

- - - - Example- (C) Carbon with 13 protons will consist of 7 neutrons instead of the original 6
        
        Radiometric dating
        
        Scientist measure the ratio of the different isotopes and calculate how many half- lives in years that have passed since an organism has fossilized or rock has formed
        
        Half--life
        
        The time it takes for 50 % of the parent isotope to decay
    - - Is one which the nucleus decays spontaneity giving off particles and energy.
        
        When an atom of Carbon --14 decays , it loses an electron and becomes an atom of nitrogen
        
        Radioactive isotopes are often used as diagnostic tools in medicine such as PET scanners
  - - - Subatomic particles are the components of an atom
        
        Electrons
        
        Negative charge
        
        mass is not included in the atomic mass bc is light
        
        Neutrons
        
        Neutrally Charged = no charge
        
        Protons
        
        positive Charge
        
        Atomic nucleus
        
        Proton + Neutrons at the core
        
        Both have almost the same identical mass. Roughly 1 dalton
  - - - This is defined as the capacity to cause change for instance "to do work"
        
        potential energy
        
        is energy that matter possesses because of its location or structure
        
        Example -- water running down hill, as water goes down it will move blades to do work
    - - electron shells
        
        The average distance from the nucleus
        
        The further from the nucleus the more energy they have. 1= 2 --> 2= 8 ---> 3=10. * electron on the Outer shells
        
        Nucleus------>. ( Protons + Neutrons)
        
        First Outer shell --- Max 2 electrons --> S sub shell with 1 orbital
        
        Second Outer shell --> S & P subshells which contain 1 orbital in the S and 3 orbitals in the P subshell
        
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  - - - This is measured in daltons . This is the protons + neutron
        
        When asked to find the neutrons or protons subtract the number of the given by the mass number
    - - This is the number of proton + neurons
    - - The number of protons determine the atomic number
- - - - CARBON DIOXIDE & WATER
  - - - GLUCOSE & OXYGEN
  - - - WATER 6 H2O --->
        
        SUNLIGHT ------->
        
        GLUCOSE C6H12O6
        
        +
        
        OXYGEN 6O2
- - - - The ability of water to stabilize temperature stems from relative high specific heat
        
        This is defined as the amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by I C.
        
        Calorie (cal)
        
        A calorie is the amount of heat it takes to raise the temperature of 1 g of water by 1C.
        
        likewise a calorie is also the amount of heat that 1g of water releases when it cools by 1C
        
        1 calorie = 4.184J
        
        Kilocalorie (Kcal)
        
        1,000 cal is the quantity of heat required to raise the temperature of 1kilogram of water by 1 C
        
        This is the unit we use for our calories
        
        1 joule (J) = 0.239
        
        Because of the high specific heat of water relative to other material, water will change the temperature less than other liquids when it absorbs or loses a given amount of heat
        
        Large body masses of water can absorb and store a huge amount of heat from the sun in the day time or in the summertime while warming up only a couple of degrees
        
        Heat of vaporization
        
        This is the quantity of heat of a liquid must absorb fo 1g of it to be converted from liquid to the gaseous state
        
        Water has a high heat of eveporization for similar reasons of the high specific heat
        
        Evaporative cooling
        
        This provides stability of temperature in lakes or ponds and also provides mechanisms that protect terrestrial organism from overheating
        
        Humans * Homeostasis
      - Temperature
        
        represents the average kinetic energy of the molecules in a body of matter
        
        Quantity is not measured
      - Thermal energy
        
        This reflects the total kinetic energy and thus depend on the matters volume
    - - Water is one of the few substances that are less dense as a solid than as a liquid
        
        while other materials contract and become denser when they solidify water expands
        
        Hydrogen bonding
        
        they keep molecules at "arm length" making ice about 10% less dense
        
        water reaches its greatest density at 4 C and then begins to expand as the molecules move faster
        
        10% fewer molecules in the same volume than liquid water at 4C
        
        This ability to float is due to its low density
        
        This important to life because if ice sank water masses will freeze solidly killing all aquatic life
        
        Many animals benefit from ice such as polar bears, pacific walrus, whales and capering fish. Ice has very important role in life
    - - when water molecules hold the substances together
        
        cohesion
        
        hydrogen bonding to contributes to the transport of water and dissolved nutrients against gravity.
        
        Example: Xylem in plants acts like a single molecule of water to bring water like a straw.
        
        related to cohesion is surface tension
        
        a measure of how difficult it is to break the surface of a liquid
        
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        adhesion
        
        the clinging of one substance to another that helps counter the force of gravity
        
        Example: water moving ip the column of cells in the Xylem and trough fine tubes in the cell wall
    - - Solution
        
        Liquid that is completely homogeneous mixture of two or more substances
      - Solvent
        
        the dissolving agent of a solution
      - Solute
        
        The substance that is dissolved
      - Aqueous solution
        
        is one in which the solute is dissolved in water.
        
        Water is the solvent
      - Hydration shell
        
        The sphere of water molecules around each dissolved ion
        
        Negative oxygen regions of polar water molecules are attracted to sodium cations (Na+)
        
        Positive hydrogen regions of water molecules are attracted to chloride anions (CL-)
        
        Hydrophilic and Hydrophobic substances
        
        Hydrophilic
        
        loving of water
        
        Hydrophobic
        
        non loving of water
        
        Solute concentration
        
        mole
        
        represents an exact number of objects
        
        6.02x10^23 which is Alvogadro's number
        
        There are 6.02x 10^23 molecules of sucrose , or 1mol of sucrose
        
        Molarity
        
        the number of moles of solute per liter of solution
        
        This is the most used unit of concentration by biologist fo aqueous solutions
        
        Molecular mass
        
        is the sum of the masses of all the atoms in a molecule
  - - - this is a single proton with a charge of 1+
    - - The water molecule that lost a proton
    - - proton binds to the other water molecule
    - - Acids
        
        An acid is a substance that increases the hydrogen ion concentration of a solution
        
        Example: When hydrochloric acid is added to water hydrogen atoms dissociate from chloride ions
        
        HCL ----> H^+ + CL-
        
        Having more H+ than OH- cause an acidic solution
      - Base
        
        A substance that reduces the hydrogen ion concentration of a solution is called a base
        
        They reduce the H+ concentration by accepting hydrogen ions
        
        NH3 + H+ -----> NH4+. <-----
        
        The higher concentration of OH- THAN H+ makes a solution basic
      - pH
        
        The pH of a solution is defined as the negative logarithm (base 10) of the hydrogen ion concentration
        
        1 through 6 is an acidic solution
        
        The lower the pH the stronger the acid
        
        7 is neutral
        
        Water
        
        8 through 14 is a basic solution
        
        Less H+, or more HO- than H+
      - Buffer
        
        Is a substance that minimizes changes in the concentrations of H+ and OH- in a solution
        
        This allows biological fluids to maintain a relatively despite the addition of acids and bases
        
        Response to rise in pH ------> <-------- response to drop on pH
        
        H2CO3 H+ doner acid
        
        HCO^-3 H+ acceptor base
        
        +
        
        H+ Hydrogen ion
  - - - Since Oxygen is more electronegative the electrons spend more time closer to oxygen than hydrogen
        
        Oxygen has two regions with partial negative charge
        
        these are connected by a hydrogen bond
    - - This unequal sharing of electrons in waters V shape make it a polar molecule
- - - - Chemist recognize 92 elements
        
        Element types
        
        Essential Elements
        
        Elements that an organism need in order to maintain a healthy lifestyle.
        
        Hydrogen 9.5%
        
        Nitrogen 3.3%
        
        Carbon 18.5%
        
        Nitrogen 3.3%
        
        Oxygen 65.0%
        
        Calcium 1.5%
        
        Phosphorus 1.0%
        
        Potassium 0.4%
        
        sulfur 0.3%
        
        Sodium 0.2%
        
        Chlorine 0.2%
        
        Magnesium 0.1%
        
        Trace Elements
        
        These elements are required by an organism in only minute quantities.
        
        YESSSSSS! These are essential as well but only in a small amounts. Less than 0.01% of mass
        
        Cobalt (Co)
        
        Copper (Cu)
        
        Chromium (Cr)
        
        Fluorine (F)
        
        Boron (B)
        
        Iodine (I)
        
        Iron (Fe)
        
        Manganese (Mn)
        
        Molybdenum (Mo)
        
        selenium (Se)
        
        silicon (Si)
        
        Tin (Sn)
        
        Vanadium (V)
        
        zinc (Zn)
  - - - Emergent properties of a compound
        
        NaCL
        
        1:1 ratio, The metal sodium + poisonous gas chlorine
        
        H20
        
        2:1 ratio, water + oxygen
- - - - This is sharing of of a pair of valence electrons by two atoms
        
        Two or more atoms held together by covalent bonds a molecule
        
        Examples : H2, O2,
        
        Strongest covalent bond
      - Non-polar covalent bond
        
        This happens when an atom is bounded to a more electronegative atom, which causes an uneven paring of electrons
        
        H2O- joined by a single hydrogen bond the molecule is polar because the positive charge on the hydrogen attaches to the more electronegative side of the oxygen
      - Polar covalent bond
        
        The electrons are shared equally because the two attains have the same electronegativity
        
        O2
        
        H2
    - - The chemical that involves the electrostatic attraction between oppositely charged ions
        
        cation
        
        Positively charged ion
        
        anion
        
        Negative charged ion
        
        ionic compounds or salts
        
        NaCL
        
        Sodium atom has a total of 11 electrons, 1 valence electron on the third electron shell
        
        Chlorine has 17 electrons , with 7 in the valence electrons in its valence shell
        
        When those two atoms meet the alone valence electron transfers to the chloride atom . This fulfills the octet rule .
        
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    - - Is an attraction between a hydrogen atom carrying a partial positive charge and an electronegative charge carrying a negative charge
        
        Vander Waals interaction
        
        these occur between transiently positive and negative regions of molecules
        
        These can be weak individually but also strong when they are together