Search for notes by fellow students, in your own course and all over the country.
Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.
Title: Chemistry Basics
Description: Good notes taken on atoms, elements, chemical bonds, water, and pH.
Description: Good notes taken on atoms, elements, chemical bonds, water, and pH.
Document Preview
Extracts from the notes are below, to see the PDF you'll receive please use the links above
Chapter 2: Chemistry
9/15/15 8:42 PM
Matter: anything that takes up space and mass
• Solid (ex
...
blood)
• Gas (ex
...
H-H
" number of lines shows the amount of covalent
bonds
Life began in water
• Most important molecule on Earth
• All organisms are 70-90% water
• Polar covalent bond
o Atoms do not share electrons equally
o Oxygen is more electronegative than hydrogen
o Electrons spend more time around the oxygen
nucleus than the hydrogen nuclei
o Oxygen end becomes slightly negative/hydrogens
become slightly positive – not an ionic bond or ions
• Hydrogen bond – slightly positive hydrogen of one water
molecule attracted to the slightly negative oxygen
• Properties of water:
o Solvency
" Hydrophilic – molecules attracted to water
" Hydrophobic – molecules not attracted to water
" Water causes NaCl to dissociate
o Cohesion
" Ability of water molecule to cling to each other
due to hydrogen bonding
o Adhesion
" Ability of water molecules to cling to other polar
surfaces
o High surface tension
" Water molecules at the surface cling more
tightly to each other than to the air above
" Mainly due to hydrogen bonding
o High heat capacity
" The many hydrogen bonds linking water
molecules allow water to absorb heat without
greatly changing its temperature
" Temperature of water rises and falls slowly
o High heat of vaporization
" Takes a great deal of energy to break H bonds
for evaporation
" Heat is dispelled as water evaporates
o Varying density
Acids and bases
• Water dissociates into an equal number of hydrogen ions
(H+) and hydroxide ions (OH-)
o Hydrogen (H+) is more acidic
" Lemon juice, vinegar, coffee
o Basic solutions (low H+ concentration, OH-)
" Milk of magnesia, ammonia
" Either take up hydrogen ions or release
hydroxide ions
• pH is the mathematical way to indicate the numeber of
hydrogen ions in a solution
• pH scale ranges from 0-14
o below 7 is acidic – more H+ than OHo above 7 is basic – more OH- than H+
o 7 is equal – H+ to OH• Buffers help to balance pH
9/15/15 8:42 PM
9/15/15 8:42 PM
Title: Chemistry Basics
Description: Good notes taken on atoms, elements, chemical bonds, water, and pH.
Description: Good notes taken on atoms, elements, chemical bonds, water, and pH.