Ch.2 Intro to Chemistry Flashcards
Matter
anything that has mass and occupies space
Weight
pull of gravity on mass
3 states of matter
- solid
- liquid
- gas
Solid
definite shape and volume
Liquid
changeable shape; definite volume
Gas
changeable shape and volume
Energy
capacity to do work or put matter into motion
Two forms of energy:
- Kinetic energy: energy in motion
- Potential energy: stored energy to be released
Forms of energy
- Chemical
- Electrical
- Mechanical
- Radiant (Electromagnetic)
Energy Conversions
- Radiant energy can be converted to chemical
energy - Chemical energy can be converted to mechanical
energy - energy conversions are not 100% efficient – extra
energy released as heat.
What elements make up 96.1% of living organisms?
- Oxygen (O)
- Carbon (C)
- Hydrogen (H)
- Nitrogen (N)
What elements make up 3.9% of living organisms?
- Calcium (Ca)
- Phosphorus (P)
- Potassium (K)
- Sulfur (S)
- Sodium (Na)
- Chlorine (Cl)
Protons
- located in nucleus
*1 Positive charge
*1 amu - Number of protons = atomic number
Electrons
- Orbit around nucleus
– 1st orbit can hold up to 2 e-
–2nd orbit can hold up to 8 e- - 1 negative charge
- 0 amu
- Number of electrons =
number of protons
Neutrons
- located in nucleus
- No electrical charge
- 1 amu
Atomic mass =
Number of protons + Number of neutrons
Atomic weight
average mass of all stable atoms for that element
Atomic number
number of protons
Atomic number - mass number =
number of neutrons
Atomic number - number of electrons =
electrical/ net charge of ion
an ion
an atom that has either gained or lost electron(s)
Isotopes
- atoms of the same element
- Ex: Iodine - same # of protons and electrons but different # of neutrons
- can often be unstable (break down over time to release energy), used medically for diagnosis and harmful
How can isotopes be used medically for diagnosis?
Ex: radioactive iodine (Iodine 131, normal iodine-126) can be used to test for thyroid function
How can isotopes be harmful?
Radon gas results from decay of uranium in the ground, can cause cancer
molecule
- two or more atoms bonded together (H2)
- two or more of the same element bonded together (O2)
Compound
- two or more different kinds of atoms bonded together
- Ex: (C6H12O6) Glucose, (H2O) Water, Salt (NaCl), Methane (CH4)
Chemical bonds
- forces that hold together atoms of a molecule or compound
- bonding depends on the # of electrons in the outermost (valence) shell
Octet Rule
stable if valence shell holds max number of electrons
Types of Chemical Bonds
- ionic
- covalent
- hydrogen
Ionic Bond
Electrons given away or accepted
- positive and negative charge
Covalent Bond
Involve the sharing of electrons between atoms
positive charge
more protons than electrons
negative charge
more electrons than protons
polar covalent
unequal sharing of electrons
- compounds tend to dissolve in water
non polar covalent bond
equal sharing of electrons
- compounds tend to not dissolve in water
Hydrogen bonds
form due to the polar covalent bonds of molecules
- Ex: hydrogen bonds between water molecules
Inorganic compounds
- water
- salts
- acids/ bases
Organic compounds
macromolecules
contain carbon-hydrogen bonds
- proteins
- carbohydrates
- lipids
- nucleic acids
Properties of water
- high heat capacity: requires high energy input in the form of heat to change temp
- high heat of vaporization: requires high energy input to change it from liquid to gas
- universal solvent: dissolves most molecules
- reactivity: in chemical reactions
- cushioning
- cohesion + surface tension
- Ice is lighter than water
- transparent: color less
Salt
- inorganic compound that dissolves in water and charged particles called electrolytes
Ex: CaCO3 (calcium carbonate) –> Ca^2+ + CO3^2-
Acid
substances that releases H+ (proton donor)
Base
substances that take up H+ (proton acceptors) reduce the acidity of the solution
EX:
1. NaOH –> Na+ + OH-
2. OH- + H+ –> H2O
Strong acids and bases
they are completely ionized (dissociates) in solution and can affect the pH of the solution
pH scale
- measures the amount of free H+ and free OH- in a solution
- pH homeostasis is essential
- 0-7 = acidic
- 7-14 =basic
Buffers
- maintain pH
- are weak acids and bases that donate or accept protons to help resist changes in pH, they do not completely dissociate
- Ex: carbonic acid -bicarbonate system (blood)
carbonic acid -bicarbonate system (blood)
- H2CO3 (carbonic acid = weak acid) –> HCO3- + H+ (bicarbonate + hydrogen ions)
- Response: rise in pH –> becomes more basic –> compound dissociates - HCO3- + H+ (bicarbonate + hydrogen ions) –> H2CO3 (carbonic acid = weak acid)
- Response: drop in pH –> becomes more acidic
Dehydration synthesis
- 2 monomers
- water is released –> removal of OH from one monomer and removal of H from the other monomer at the site of bond formation
- a covalent bond links 2 monomers into a macromolecule
Ex: Glucose + Fructose –> Sucrose
Hydrolysis
- Macromolecule linked by a covalent bond
- water is added –> monomers are released by adding OH to one monomer and H to the other monomer
- 2 monomers
Ex: Sucrose –> Glucose + Fructose
Carbohydrates (sugars)
- polymer of monosaccharides
- monosachraides: glucose and fructose
function: - energy source: ATP
- energy storage for animals: glycogen
- energy storage for plants: cellulose
- used for structure as proteoglycans
Lipids
- polymer of polysaccharides
- molecules that are NOT soluble in water
- 3 types: triglycerides, phospholipids, steroids
Triglycerides
- a type of lipid
function: - energy storage
- cushioning
- insulation
- good fats: unsaturated
- bad fats: saturated
- Ex: LDL (saturated) is bad cholesterol
phospholipids
- a type of lipids
function: - form cell membranes
Proteins
- polymers of amino acids
function: - structure
- enzymes
- contraction
- immunity
- regulation
- carry oxygen
- hormones
Steroids
- a type of lipids
function - cell membranes
- steroid hormones
- vitamin D production
Enzymes
- not used up in reaction, speed up reaction and lowers energy of reaction
1. Substrates bind at active sites –> enzyme changes to hold shape to hold substrates –> forms E-S complex
2. internal rearrangements leading to catalysis occur
– energy is absorbed –> bond is formed -> water is released
3. product released –> enzyme returns to original shape and available to catalyze another reaction
Nucleic acids
- polymer of nucleotides
- 2 types: DNA and RNA
nucleotide
made up of phosphate, sugar and base
- make up nucleic acids
ATP
- a modified nucleotide
- ATP –> ADP + P + Energy
enzyme vs catalyst
enzyme:
- organic
- speeds up reaction by converting substrate into product
catalyst:
- inorganic
- increase or decrease the rate of a chemical reaction but remain unchanged
