Chemistry T2 finals

• An ionic bond is formed by an electron transfer between metals and non-metals.
• A covalent (molecular) bond forms when electrons are shared. Nonmetals form a covalent bond.
• Ionic Compound properties:

  • solid
  • hard and brittle
  • high melting and boiling points
  • solubility in water
  • conduct electricity when melted and dissolved in water
• Ionic Bonds look like

  
• Covalent compound properties:

  • soft
  • low melting and boiling points
  • solubility depends on polarity
  • does NOT conduct electricity
• Covalent compounds look like...

  
• In a single bond, 2 total electrons are shared.
• In a double bond, 4 total electrons are shared.
• In a triple bond, 6 total electrons are shared.
• In a metallic bond, electrons behave by flowing freely to conduct electricity and heat. Known as a sea of electrons.
• Metals form a metallic bond.
• Metallic Bond Properties:

  • malleability
  • ductility
  • hardness
  • high electrical conductivity
• Nonpolar Bond: Electrons are shared equally. The difference in electronegativity is zero.
• Polar Bond: Electrons are shared unequally, Difference in electronegativity is between 0.4 - 2.0.
• Finding molecular polarity:

  
• Nonpolar molecules are symmetrical which results in a symmetrical distribution of change.

  
• Polar molecules are asymmetrical resulting in an asymmetrical distribution of charge.

  
• Intermolecular force is the force of attraction between molecules.

  
• Hydrogen Bond: only occurs when H - F, H - O, or H - N are in a bond.

  
• The relationship between boiling point and strength of intermolecular forces is that strong intermolecular forces result in higher boiling points.
• Empirical formula: The simplest whole number ratio of atoms of each element present in a compound.

  
• Isomer: A molecule with the same molecular formula but a different structural formula
• Entropy: The measure of the disorder of a system. The higher the entropy, the more disordered the system.
• If gas turns to liquid then the entropy decreases since the liquid has less disorder than a gas.
• When the temperature is increased, the rate of reaction increases because there is an increase in effective collisions.
• When surface area is increased by turning the substance into a powder, the rate of reaction increases because the particles can have more effective collisions.
• When concentration is increased, the rate of reaction increases because there are more particles to increase the frequency of effective collisions.
• Exothermic: releases energy making heat reaction negative.

  
• Endothermic: absorbs energy, heat of reaction is positive.

  
• Catalyst: speeds up the reaction rate by providing an alternate pathway that lowers the activation energy.

  
• Synthesis: a reaction in which two or more substances combine to form a new compound.

  
• Decomposition: a reaction in which a single compound breaks down to form two or more substances.

  
• Single Replacement: one element replaces another element in a compound.

  
• Double Replacement: a chemical reaction where two elements in different compounds trade place.

  
• Combustion: a rapid reaction between oxygen and fuel that results in fire.

  
• Exothermic Reaction Diagram: reactants are higher than products.

  
• Endothermic Reaction Diagram: products are higher than reactants.