Chemistry FINAL

• Matter is anything that has mass and takes up space.
• A solid has a definite shape and volume
• A liquid has a definite volume and takes up the shape of its container
• gas does not have a definite shape or volume
• A physical change is a difference in appearence
• A chemical change is a difference in composition
• An element is a substance that cannot be broken down
• A compound is a substance made of two or more elements
• A pure substance is a substance made of one type of atom
• A homogeneous mixture has a uniform composition (cannot see individual parts)
• A heterogeneous mixture does not have a uniform composition (can see layers and individual materials in mixture)
• Periodic Law states that elements are listed in order of their atomic number and are grouped into families with elements with similar properties
• Atomic number is the number of protons in an atom
• Atomic mass is the mass of one molecule of an element
• The mass number is the number of protons + neutrons
• Isotopes are 2 or more forms of the same element
• The octet rule states that atoms are most stable when they have 8 electrons in their valence shell
• A cation is a positive ion (paw-sitive)
• An anion is a negative ion
• A diatomic molecule has two atoms bonded together
• What are the diatomic molecules?

  Hydrogen, Nitrogen, Fluoride, Oxygen, Iodine, Carbon, Bromine
• What is the mnemonic device to remember diatomic molecules?

  Have No Fear Of Ice Cold Beer
• How do you determine the # of significant figures in multiplication and division?

  you pick the figure with the LEAST number of sig figs
• How do you determine the # of significant figures in addition and subtraction?

  you copy the number with the least number of decimal places
• How do you determine the number of significant figures in scientific notation?

  All final zeroes before the x10
• How many sig figs are in this?$3.965 \times 10^6$


  4 sig figs
• What is the first rule of significant figures?

  non-zero numbers are ALWAYS significant
• What is the second rule of significant figures?

  "captive zeros" (zeros between non-zero numbers) are always significant
• What is the third rule of significant figures?

  All final zeros to the right of the decimal are significant (following non-zero numbers)
• What is the fourth rule of significant numbers?

  place holder zeros are not significant
• How do you remove place holder zeros?

  rewrite the number in scientific notation
• How many significant figures are in the following?$70.07$


  4
• How many sig figs are in the following? $3 \times 10^{-3}$


  1
• How many sig figs are in the following?$0.0009000$


  3
• How many sig figs are in the following?$0.0680$


  3
• How many sig figs are in the following? $60$


  2
• How many sig figs are in the following? $63000.$


  5
• How many sig figs are in the following? $0.00935000$


  6
• How many sig figs are in the following? $530230$


  6
• How many sig figs are in the following? What is the final figure?

  $74.12+$$58.3+$$52.345=$$184.765$


  3 & 184.8