Inorganic chem 2

Inorganic Chemistry 2

• The law of conservation of energy/matter states that matter can neither be created or destroyed 

• matter= anything that takes up space and has mass

  • So how do you transform matter into new things?

    • Chemical reactions 

• Chemical Bonding

  • Chemical bonding allows you to link atoms together to create new compounds or molecules 

    • The linked atoms have different properties from the starting atoms 

    • Na( sodium) + Cl( chlorine) = NaCl( table salt)

  • Bonding neither destroys nor creates new matter, it transforms matter

  • How is bonding achieved?

    • Through electrons ( the personality )

• Common types of bonds

  • Ionic bonds involve the attraction of opposite electrical charges.

  • One atom donates e- to another atom

  • Before atoms interact for the first time the atoms are electrically neutral 

  • This is because # of protons equals # of electrons 

• Ions

  • Atoms that have an electrical charge

  • An atom because an ion (charged) when it either gains or loses electrons( because # protons no longer equals # of electrons

  • After this happens they don't go back

  • When an atom loses electrons(- ) charged) it becomes + charged 

  • (+) charged ions are called cations 

  • Atoms that gain electrons become (-) charged 

  • Negative charged ions are called anions

• Electrolytes

  • Cations and anions that are dissolved in water are called electrolytes

  • VERY IMPORTANT( help with nerve impulse conduction which relies on electrolytes) Na, K

  • Also, muscle contractions rely on calcium ions-electrolytes 

• Common types of bonds 

  • Covalent bonds( sharing bonds)- from between two atoms when they share PAIRS of electrons

    • Covalent bonds are stronger than ionic bonds because they are sharing bonds between two atoms

    • The more electron pairs being shared the stronger the bond

    • Single bond weaker than third bond strong

    • Only parcial is coming from polar bonds 

• Covalent Bonds 

  • Covalent bonds can be: 

  • Non-polar ( equal sharing of e- pairs)\

  • Polar ( unequal sharing of e- pairs)

    • This results in partial charges in the atoms that are unequal sharing electrons

    • 

    • Single pair- because they are only connected to the N 

• Hydrogen bonds

  • Their result from partial charges, which are created by polar covalent bonding

  • Hydrogen dons are weak interactions that happen between polar covalent molecules. 

    • They do not exchange they are just extracted from each other.

  • The individual interactions are weak but multiple hydrogen bonds can result in a strong bond.

  • For this to occur, one molecule must have at least a partially positive and partially negative charge.

• DNA is a double helix, they are connected by hydrogen bonds

  •  

• Water can dissolve ionic compounds by forming hydrogen bonds with ions

• • Hydrogen bonds is essential to earth and life

• Water

  • Water is essential for life

  • Solutions( solute+solent(water): molecules , nutrients, ions,etc

  • PH

    • Acids, bases, buffer

  • Water is polar molecule and therefore can form hydrogen bonds ( partial charges)

    • Hydrogen bonding confers on water many different special properties

      • Temperature

      • Density

      • Cohesion and adhesion

• Hydrogen Bonds give water unique properties

  • Heat storage

    • Water temperature changes slowly and hold temperature well

  • High Heat of vaporization(steam)

    • At high temp, hydrogen bonds can be broken

      • Water requires tremendous heat energy to vaporize because of all the hydrogen bonds that must be broken

      • High specific heat

  • Heavy of fusion(ice formation)

    • Few hydrogen bonds break at low temp

      • Water becomes less dense as it freezes because hydrogen bonds stabilize and hold water molecules farther apart expands when frozen

    • Collectively means water is stable 

• Hydrogen bonds are sticky

  • Water molecules are sticky 

    • Cohesion- when one water molecule is attracted to another water molecule

      • Gives rise to surface tension( pressure)

    • Adhesion-when polar molecules other than water stick to a water molecule

      • Gives rise to capillary action( circulation) 

    • These properties allow nutrients to circulate in plant and animal systems

  • Since water is highly polar

    • In solution, water molecules tend to form the maximum number of hydrogen bonds

      • Hydrophilic molecules are attracted to water and dissolve(interact) easily in it( needs to be able to form hydrogen bonds

        • Hydrophobic molecules are repelled by water and do not dissolve 

        • Ex. oil

      • These molecules are non-polar and do not form hydrogen bonds( don't have either a partially charged atom or a fully charged atom)