Chemistry day 3

Chemistry day 3

1. Densities

   • Density = mass/volume
     • rectangular volume: mass*length*width
     • Circular volume: 4/3*π*r^3

2. Atoms

   • John Dalton created what would become the building blocks of 3 chemical laws.
     • 1. Law of conservation of mass- Mass is not created, decomposed, or destroyed. A chemical reaction will have a constant mass.
       • Law of Definite Proportions-Atoms have definite mass, therefore compounds containing elements in definite proportions by mass. (Pure water will always have the same mass no matter where you get it.)
         • Law of Multiple proportions- Two elements that form more compounds do so in a way that the masses of one element is related to the fixed mass of the other in ratios of small whole numbers.
   • atomic symbols are a one (or two) letter notation representing an atom of a particular element. The first letter is capital followed by lower case letters
     • Atomic symbols have the Atomic mass to the upper left and atomic number to the lower left.
   • Atoms have a nucleus in the middle made up of positive protons and neutral neutrons, with electrons surrounding the nucleus.
     • This model was discovered through multiple experiments throughout the years, such as Tomson's Cathode-Ray experiment, Milliker's oil-drop experiment, and Rutherford's Gold Leaf experiment to determine these facts.
     • Protons: 1 AMU, determines which element it is.
       • Neutron's- 1AMU, determines Isotope.
         • Electron- virtually massless, negative and determines Ion.
     • Average Atomic mass is = ((mass of an isotope)*(abundance of the isotope) + (mass of isotope 2)*(abundance of isotope 2)... )/(how many isotopes there are.)