Matter Flashcards
Pure substance
Matter that is made up of only one type of particle.
Ex. Copper (Cu)
Mixture
Two or more pure substances mixed together.
Each substance retains its own set of chemical and physical properties.
Unlike pure substances, mixtures can ALWAYS be separated by physical means.
Ex. Salt water
Pure Substance - Elements
Substances made up of one type of atom.
Can NOT be separated by any physical or chemical process.
Ex. Gold (Au), Carbon (C), etc.
Elements - Metals
Gray, shiny, can be shaped, conductors, and mostly solid.
Elements - Nonmetals
Dull, colorful, brittle, insulators, and can be solid, liquid, or gas.
Pure substances - Compounds
Particles made of two or more different atoms chemically bonded together.
Ex. Carbon Dioxide (CO2), Water (H2O), etc.
Compounds have only one set of properties.
They can NOT be separated by any physical means.
Can ONLY be separated by a chemical reaction.
All compounds can be written as a chemical formula.
Polyatomic Ions
Compounds that have an electrical charge.
Written in the upper right corner of an compound in chemical formulas.
Covalent Compounds
A compound made of 2 nonmetals.
Ionic Compounds
A compound made of 1 metal and 1 nonmetal.
Mixture - Heterogeneous
A mixture that is NOT uniform (hetero = different).
You can see the different parts.
Suspencion
When a heterogeneous mixture is left alone and separates it is known as suspencion.
Colloid
When a heterogeneous mixture is left alone and does not separate it is known as a colloid.
Mixture - Homogeneous
A mixture that is uniform (homo = same)
Can not see the different particles.
AKA a solution.
Compounds vs. Mixtures
Compounds -
Homogeneous
Separated by chemical means
Different properties from its components
Definite compositions (H2O2)
Mixtures -
Homogeneous OR heterogeneous
Separated by physical means
Components retain their properties
No definite composition (little salt + lots of water = salt water, lots of salt + little water = salt water)
Physical Properties
Properties that can be observed or measured.
Ex. Color, shape, size, odor, mass, melting / boiling point, etc.
Two types of phys. prop. intensive, and extensive.
Intensive Phys. Prop.
Property that DOES NOT change with the amount of substance present.
Ex. Color, density, texture, melting / boiling point.
Extensive Phys. Prop.
Property that DEPEND ON the amount of matter present.
Ex. Mass, size, volume.
Chemical Properties
How a substance reacts with another substance.
Ex. Flammability, reactivity to acids, ability to rust, etc.
States of Matter - Solids
Particles packed close together
Particles are organized
Particles have fixed position
Definite shape and volume
Vibrating and rotating motion
States of Matter - Liquids
Particles are farther apart than solids
Particles are free to slide past one another, able to flow
Particles have higher energy that solids
Definite volume, no definite shape
States of Matter - Gases
Particles very far apart from each other
Particles travel in a random manner
Particles have the highest energy
No definite shape or volume
Low density
Compressible
Phase Changes - Melting
Solid —–> Liquid
Phase Changes - Freezing
Liquid —–> Solid
Phase Changes - Evaporation
Liquid —–> Gas
Phase Changes - Condensation
Gas —–> Liquid
Phase Changes - Sublimation
Solid —–> Gas
Phase Changes - Deposition
Gas —–> Solid
Endothermic
A phase change that absorbs heat
Ex. Melting, evaporating, sublimation
Exothermic
A phase change that releases heat
Ex. Freezing, condensation, deposition
Physical Change
Does NOT change the chemical composition (chemical formula)
Ex. Phase changes, dissolving, separation of mixtures
Seperation - Filtration
Separates a mixture by the size of the particles
Seperation - Distillation
Separates a mixture by boiling points
Chemical Change
AKA reactions
Chemical bonds are broken and reformed into new compounds
Can be written as an equation
Ex. H2 + O2 —> H2O
Signs of a chemical change
Change of color
Effervescent (forms a gas)
Forms a precipitate (a solid that can not dissolve)
Temperature change
“Billiard Ball Model” - Dalton’s Atomic Theory (1803)
Atoms are small, solid, dense, and spherical
Atoms make up all elements
Atoms of the same element are identical
Compounds are WHOLE NUMBER ratios of atoms
Chemical reactions are when compounds are broken and reformed
“Plum Pudding Model” - Thomson (1897)
Immobile electrons
Cathode Ray Tube Experiment
Discovered the electron, and they were negative
“Atomic Model” - Rutherford (1911)
Nucleus contained protons and neutrons
Electrons moved outside of the nucleus
Gold Foil Experiment
Discovered the atom was mostly negative space
Discovered the positive, small nucleus in the center
“Planetary Model” - Bohr (1913)
The nucleus is positively charged
Electrons were located in shells (fixed orbits)
Electrons can move to other shells
Millikin’s Oil Drop Experiment (1916)
Oil drop experiment discovered the weight of an electron and the exact charge of an electron
Schrodinger (1926)
Electron cloud of probability
Heisenberg Uncertainty Principle (either the position OR the speed can be known about an electron, NOT BOTH)
Cat thought experiment (electrons move so fast they are everywhere in the cloud at once but also nowhere at any one time)
Chadwick (1932)
Discovered the neutron with Rutherford
The Atom
There are 2 regions in an atom: the nucleus, and the electron cloud
There are 3 parts in an atom: protons, neutrons, and electrons
Nucleus
Dense
Positively charged
Center
Small
Electron Cloud
Empty space
Negatively charged
Majority of volume
Outside the atom
Protons
Located in the nucleus
Positively charged
Has mass
Neutrons
Located in the nucleus
No charge
Has mass
Electrons
Located in the electron cloud (outside of the atom)
Negatively charged
No mass
How to read the periodic table
Top # = Atomic #
Middle Letter(s) = Elemental Symbol (Ex. Cu, N)
Word = Elemental name
Bottom # = Average atomic mass
Atomic Number
Number of protons in the nucleus
Average Atomic Mass
Average based on percent occurrence of the mass numbers of isotopes
Ions
Same element with different electrons from neutral
Cation
Positive ion
Electrons are LESS than protons
Anion
Negative ion
Electrons are MORE than protons
Isotopes
Same element with different mass numbers from each other
Different number of neutrons
Ex. Sulfur -32 = 95.002%, Sulfur -33 = 0.76%
Calculating Average Atomic Mass
- Make sure all percentages are in decimal form (58.8% –> 0.588)
- Multiply the mass of each isotope by the decimal
- Add the products
Radioactivity
Decomposition of the nucleus (nuclear change)
All elements above #83 are normally radioactive
Becquerel discovered radioactive decay
Radioisotopes
Isotopes that are radioactive
Ex. Carbon -14
Fission
Splitting of an atom’s nucleus (occurs naturally on Earth)
Ex. Nuclear reactors, nuclear bombs
Fusion
2 small nuclei coming together to make 1 nucleus
Ex. Celestial stars (like the sun)
Half Life
Time it takes for the mass of a radioactive material to decay by half
