Chapter 3: Matter, Energy, and Life Flashcards
Atom
the smallest particle of an element that retains all of the properties of that element; Democritus was a Greek philosopher that described the concept of an indivisible, invisible particle that made up all things; he
coined the term atom from the word atomos which means uncuttable.
What does John Dalton’s atom theory state?
- All elements are composed of atoms.
- Atoms of the same element are identical (and atoms of different elements are different).
- Atoms of different elements may combine to form compounds. (With whole number ratios)
- Even in chemical reactions, atoms do not change when separated from their original compounds.
What are the three basic types of subatomic particles?
- Protons (positively charges with mass of 1 amu)
- Neutrons (no charge with mass of 1 amu)
- Electrons (negatively charged with a mass of 1/1840 amu)
What did Ernest Rutherford do?
Received Nobel Prize in Chemistry in 1908 because he revolutionized J.J. Thomson’s Plum Pudding Model into a model with a separate nucleus and electron cloud. He identified the positive nucleus with his famous “gold foil”
experiment.
What does the atomic number represent?
The number of protons
What does the mass number represent?
The number of protons and neutrons added up
Isotope
an atom with a different number of neutrons than a regular atom of that element would
Coumpunds
two or more atoms chemically combined
Molecule
the smallest unit of a compound
What are the two types of chemical bonds?
- Ionic
- Covalent
Ionic Bonds
form when electrons are transferred or accepted between atoms.
Covalent Bonds
form when atoms share electrons; these bonds are stronger than ionic.
Ions
an atom with a different number of electrons than a normal atom of that element would have; this makes the atom postive or negative
What are the two types of ions?
- Cation
- Anion
Cation
positive ion (when an election is lost)
Anion
negative ion (when an election is gained)
pH
The pH scale indicates the acid/base qualities
of a substance; pH is logarithmic so each number on the scale is 10 times greater than the number before.
Acid
substance that gives up hydrogen ions
(H+) in solution. pH range is 1-6
Base
substance that gives up hydroxide ions
(OH-) in solution. pH range is 8-14
Organic Compounds
The molecules of life:
- Lipids – commonly called “fats”, include oils and waxes.
- Carbohydrates – hydrated carbon atoms
- Proteins – built by amino acids, enzymes are specialized proteins.
- Nucleic Acids – types include RNA and DNA
Energy
the ability to do work
Kinetic Energy
the energy of motion
Potential Energy
the energy of postion or storage
How is energy measured?
Energy can be measured by joules, calories, or other
*1 calorie = 4.184 joules
Heat
Heat is a form of energy that can be transferred between objects; If heat increases, molecular motion increases. Heat may cause objects to change
state (solid to liquid). Heat may be transferred by
conduction, convection or radiation.
Conduction
energy transferred by direct contact
Convection
enery transferred by mass motion of molecules
Radiation
energy transferred though electromagnetic radiation
The First Law of Thermodynamics
energy is not created or destroyed but conserved.
The Second Law of Thermodynamics
with repeated transfers, the “quality” of energy is lost leading to disorder or entropy.