GEN CHEM

• Matter


  Anything that occupies space and has mass
• Kinetic energy


  Keeps the molecules apart and moving around and is a function of the temperature of the substance
• Matter


  Anything that has volume (occupies space) and mass (a measure of the amount of particles the matter contains)
• Chemistry


  The study of matter, its properties, and the changes it undergoes
• Particle nature of matter

  • Matter is composed of many tiny particles of one or multiple types of substances
  • Spaces between the individual particles are very large compared to the sizes of the particles
  • Particles attract each other
  • All particles of the same substance are identical to each other in every way
  • Different substances are made of different particles
  • All matter is made of extremely tiny particles (much, much smaller than cells)
  • Particles of matter are always moving
• States of matter

  • Solid
  • Liquid
  • Gas
  • Plasma
• Bose-Einstein Condensate


  Low-density gasses that are cooled to temperatures very close to absolute zero
• Phase changes of matter

  1. Evaporation/Boiling

  2. Convection

  3. Condensation

  4. Solidification

  5. Sublimation

  6. Deposition

  7. Melting

  8. Freezing

  9. Filtration

  10. Ionization

  11. Recombination
• Physical properties of matter

  • Intensive properties (color, odor, taste, luster, malleability, ductility, conductivity, hardness, melting/freezing point, boiling point, density)
  • Extensive properties (weight, volume, length, width, mass, surface areas)
• Chemical properties of matter

  Properties that can only be measured by changing its composition
• Basic terminologies

  • Matter
  • Substance (Element, Compound (Organic, Inorganic), Oxides, Acids, Bases, Salts)
  • Mixture (Homogeneous, Heterogeneous (Colloids, Suspensions))
• Accuracy


  The closeness of a measurement to the accepted value
• Precision


  The agreement among the several measurements that have been made in the same way
• Significant figures


  Digits of a number that are reliable and necessary to indicate the quantity of something
• Rules on determining significant figures

  1. Non-zero digits are always significant

  2. All zeroes between two significant digits are significant

  3. Leading zeroes are not significant

  4. Trailing zeroes and ONLY significant when a decimal point is present

  5. The sums and differences must be rounded off to the least number of decimal places

  6. The multiples and quotients must be rounded off to the least number significant digits

  7. A final zero or trailing zeros in the decimal portion ONLY are significant

  8. For addition and subtraction: Look at the places to the decimal point. Add or subtract in the normal fashion, then round the answer to the LEAST number of places to the decimal point of any number in the problem

  9. For Multiplication and Division: The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer
• Atomic symbol


  A code for a chemical element, normally consists of one or two letters from the latin alphabet and are written with the first letter capitalized
• Significant digits


  Digits that are meaningful and not just placeholders
• Trailing zeros in the decimal portion are significant
• For addition and subtraction

  Look at the places to the decimal point, add or subtract in the normal fashion, then round the answer to the LEAST number of places to the decimal point of any number in the problem
• For multiplication and division

  The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer
• Atomic symbol


  • Earlier symbols for chemical elements stem from the classical Latin and Greek vocabulary, while later symbols were based off of new root word vocabulary/ named after a person
  • 3-letter temporary symbol may be assigned to newly synthesized/ not yet synthesized elements
• Atomic symbols


  • Pb is the symbol for Lead (plumbum in Latin)
  • Hg is the symbol for Mercury (hydrargyrum in Greek)
  • He is the symbol for Helium (a new Latin name)
• Atomic number (proton number)


  The number of protons in an element, in the left subscript position
• Mass number (nucleon number)


  Indicates a specific isotope, in the left superscript position
• State of ionization


  Indicates the ionization state, in the right superscript position
• Number of atoms


  Indicates the amount of atoms in a molecule or a chemical compound, in the right subscript position
• Ionic notation


  𝑍𝐴𝑋𝑖
• Isotopic symbol


  𝑋–𝐴
• Average atomic mass

  Equal to f1M1+ f2M2 + ... + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope
• Calculating average atomic mass

  Convert the percentages into fractions, calculate the mass numbers, then calculate the average atomic mass by multiplying the fraction with the mass number for each isotope and adding the products together
• Atomic mass unit (amu)


  A nucleon has a mass of about 1 amu, the atomic mass number for each element listed in the periodic table is the weighted average of the masses of these isotopes based on the occurrence of each isotope on Earth
• Mole


  A unit of measure that helps us compare particles of any given substance and its mass
• Molar mass


  The sum of the total mass in grams of all the atoms that make up a mole of a particular molecule, the unit used to measure is grams per mole
• Finding molar mass for compounds

  1. Step 1 - find the atomic masses of individual elements in the periodic table

  2. Step 2 - count how many atoms there are for each element

  3. Step 3 - find the molar mass using the formula: Molar Mass = no. of atoms × atomic mass
• Molar mass in percent composition

  mass% = atomic mass of element / total molar mass of compound × 100<|>mass% = mass of solute / mass of solution × 100
• Mole and Avogadro's number


  1 mole of a substance contains exactly 6.02214179 × 10^23 elemental entities, called Avogadro's Number
• Converting between mass, mole, and number of particles

  1. Mass to Mole - divide mass by molar mass

  2. Mole to Mass - multiply moles by molar mass

  3. Mole to # of Particles - multiply moles by Avogadro's number

  4. # of Particles to Mole - divide # of particles by Avogadro's number
• Molecular formula


  Describes the exact number and type of atoms in a single molecule of a compound, using chemical symbols and subscripts
• Empirical formula


  The simplest whole-number ratio of all the atoms in a molecule, can be the same as the molecular formula but not always
• Deriving molecular formula from empirical formula

  Multiply the empirical formula by a whole number to reach the molecular formula