Honors Chem. Mid-Term

Traditional areas of study in Chemistry
Differences between pure and applied chemistry
Pure- pursuit of knowledge for its own sake
Applied- directed toward practical goals or applications
Why study chemistry?
Explain natural world
Prepare people for career opportunities
Produce informed citizens
Distinguish between macroscopic and microscopic views
Macro- large enough to be sen by the unaided eye
Micro- can only be seen under magnification
How did Lavoisier transform chemistry?
science of observation to science of measurement
Importance of collaboration and communication
Increases likelihood of a succesful outcome
Two general steps in problem solving
Develop and plan and implement that plan
Three steps to solving numeric problems
Two steps to solving a conceptual problem
Several common physical properties
Melting + Boiling points
Physical change
Some properties of a material change, but the composition does not change
Substance vs mixture
Substance- has a uniform and definite composition
Mixture- physical blend of 2 or more components
Homogenous vs heterogenous
Homo- compostiton is uniform throughout
Hetero-comp. is not uniform
Ways to seperate a mixture
Element vs compound
Element- simplest form of matter with unique set of properties
Compound- contains two or more elements chemically combined
Chemical change
Produces matter w/ a different composition than the original matter
Law of conservation of math
In any physical change or chemical reaction, mass is conversed
Mass vs weight
Mass- measure of amount of matter an object contains
Weight- the pull on a given mass by gravity
Celsius to Kelvin conversion
K = C + 273
Equation for calculating density
density = mass/volume
Democritus’s atomic theory
Atoms are indivisible and indestrusctible
Dalton’s atomic theory
1. All elements are composed of tiny indivisible particles.
2. Atoms of element are identical. Different element = different atoms.
3. Atoms of different elements can physically mix or chemically combine.
4. Atoms of one element are never changed into atoms of a different element.
Subatomic particles
Rutherford’s atomic model
1. Protons and neutrons located in nucleus
2. Electrons distributed around nucleus and occupy almost all volume of the atom
Element with different number of neutrons
Atomic number
Number of protons in the nucleus of an atom
Mass number
Total number protons and neutrons
Bohr model
An electron is found only in specific orbits around the nucleus
Distance between crests
Number of wave cycles
Quantum vs Classical mechanics
Quantum- describes motions of subatomic particles and atoms waves
Classical- describes motions of bodies much larger than atoms
Properties of ionic compounds
1. Crystalline solid at room temp.
2. High melting points
3. conduct electricity when dissolved in water or melted
Mixtures composed of 2 or more elements, at least one of which is a metal
Ionic vs Metallic bonds
Ionic- consists of cations and anions
Metallic- consists of free-flowing valence electrons attracted to posistive metal ions
Molecular formula
Shows how many atoms of each element a molecule contains