CHEM

• Surface tension


  The force that causes liquids to form droplets
• Reason water boils at lower temperature in higher altitudes

  Lower air pressure at higher altitudes reduces the boiling point of water
• Evaporation


  The process that changes liquid to gaseous water, occurs when energy (heat) forces the bonds that hold water molecules together to break
• Ethanol (C2H5OH) molar mass is 46g/mol
• Amorphous solids


  Solids where the particles do not have orderly structures, therefore they have poorly-defined shape
• Viscosity


  A fluid's ability to resist flow, related to the mobility of the molecules in the liquid and the intermolecular forces present
• Solids have stronger attractive forces between the particles, compress less than liquids, and have fixed volume and shape
• Device for measuring viscosity of liquids

  • Ostwald Viscometer
• Phase change of matter


  Changes that occur when the system receives/loses sufficient energy or when the system's pressure changes
• Capillarity tube


  Narrow tube placed on skin opening to draw up blood sample
• Boiling point of water at sea level is 100 degrees Celsius
• Valence electrons


  Lithium has 1, Oxygen has 6
• Ice structure


  • Ice has a more open structure than water because it has more hydrogen bonds than water
• Silicon belongs to the group where the octet rule is not followed
• Non-polar molecules do not have greater electronegativity than polar molecules
• Hydrogen bromide (HBr) has one lone pair and two bonds
• To illustrate Lewis dot structures, one should know the electronegativity and valence electrons of each element
• Solutions are not always in liquid state
• Solutes do not have to be solid to make a solution
• Evaporation is liquid to gas, sublimation is solid to gas
• The amount of energy necessary to convert a liquid into a gas is called the heat of vaporization
• Non-polar has greater electronegativity than Polar

  FALSE
• Hydrogen Bromide (HBr) has lone pair and 2 bonds

  FALSE
• To illustrate Lewis dot structure of compounds, one should know the electronegativity and valence electron of each element

  FALSE
• Carbon Dioxide + Water = Seltzer

  Seltzer + Sugar = Cleaning agent like NH3

  FALSE
• Moth Balls: Sublimation Rain: Precipitation


  TRUE
• Solutions are always in liquid state

  FALSE
• Solutes don't have to be solid to make a solution

  TRUE
• The shape of a crystal depends on he arrangement of particles within it. The smallest portion of the crystal which shows the complete pattern of the particles is called a crystal lattice


  FALSE
• Evaporation - liquid to gas, Sublimation - solid to gas


  TRUE
• The amount of energy necessary to convert a liquid into gas is called heat of vaporization


  TRUE
• Octet rule


  A rule that states that atoms in a Lewis structure tend to have eight valence electrons in their outermost shell.
• Valence electrons


  The outermost electrons in an atom that are involved in chemical bonding.