76 terms

Chapter 2-1 & 2-2 Words to Know, Chapter 2-3 & 2-4, Chapt 3-Classification of Matter, Chapter 4

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Matter
Anything with mass and volume
Mass
Amount of matter in an object (Kilograms)
Inertia
Resistance to change in an object's motion
Weight
The pull of gravity on an object determines the weight (measured in Newtons)
Volume
The amount of space an object takes up (liters=liquid, cubic centimeters=solids)
Density
Mass per unit volume of an object (g/L)
Physical Properties
color, shape, hardness & texture
4 phases of matter
solid, liquid, gas & plasma
Solids
Definite shape and volume
Crystalline Solids
solids made up of crystals (particles arranged in a repeating pattern)
Amorphous Solids
solids that lose their shape under certain conditions (glass & candle wax are examples)
Liquids
No definite shape. However, they do have a definite volume. (1 Liter is 1 Liter regardless of the container it occupies) Particles are close together, but are free to move around.
Viscosity
The resistance of liquid to flow. (Honey has a high viscosity--it flows very slowly)
Gas
No definite shape or volume. (It will fill all available space in a container)
Boyle's Law
If the volume of a gas is reduced, the number of particle collisions will increase. Gas pressure will increase.
Charles's Law
The volume of a fixed amount of gas varies directly with the temperature of the gas.
Plasma
RARE on Earth-Matter is very high in energy and very dangerous to living things.
Physical Change
A change where the physical properties are altered but the substance remains the same kind of matter.
Melting
Change of a solid to a liquid
Melting Point
The temperature at which a solid changes to a liquid
Freezing
A liquid changes to a solid due to the loss of heat energy.
Freezing Point
The temperature that is equal to the melting point, yet the liquid changes to a solid
Vaporization
Change of a substance from a liquid to a gas
Evaporation
Vaporization at the surface of a liquid
Boiling Point
Temperature at which liquid boils (when the particles inside and on the surface of a liquid change to a gas and travel to the surface)
Condensation
When a gas changes to a liquid
Sublimation
When a solid changes directly to a gas
Chemical Properties
Properties that describe how a substance changes into a new substance
Flammability
The ability to burn
Chemical Reactions
A chemical change in which a new substance with different physical and chemical properties is created.
Homogeneous matter
Has identical properties throughout
Heterogeneous matter
Matter that has parts with different properties
Mixture
Matter with two or more substances mixed together but not chemically combined
Heterogeneous Mixture
'Least mixed' of all mixtures. Mixture that doesn't appear to be the same throughout.
Homogeneous Mixture
'Well mixed'. Mixture that appears to be the same throughout. (Particles are very small and not easily recognized)
Solution
'Best mixed'. Type of homogeneous mixture formed when one substance dissolves into another
Alloys
Metal solutions where solids are dissolved into solids
Pure substance
Made of only one kind of material with definite properties. (Homogeneous matter)
Element
The simplest pure substance. They cannot be broken down into simpler substances. (Beware: Not all pure substances are elements)
Atom
The smallest particle of an element with all of the same properties.
Chemical Symbols
Representation of elements. (If two letters make up a symbol, the 1st letter is capitalized followed by a lower case letter)
Compound
Two or more elements chemically combined. (Ex. Sugar, Oxygen, Carbon Dioxide)
Molecules
Two or more atoms chemically bonded together. The smallest part of a compound that has all the properties of the compound.
Chemical Formulas
Combinations of chemical symbols. Most represent compounds.
Subscripts
Small number written to the right side of an element in a chemical formula.
Chemical Equation
Description of a chemical reaction using symbols.
Coefficient
The number placed in front of (left side) the chemical symbol in order to balance the equation.
Solvent
Substance that does the dissolving
Solute
Substance that is dissolved in the solution
Insoluble
Substance that doesn't dissolve in water (oil)
Soluble
Substance that will dissolve in water (sugar, etc)
Suspensions
Heterogeneous mixture that can separate over time, generally cloudy or with floating particles that are visible to the eye (You can filter out particles)
Colloids
Particle sizes are between a solution and a suspension (particles cannot be filtered out) Ex. Fog (It will scatter light)
Democritus
Greek philosopher who named the smallest piece of matter an atom
Dalton
Proposed the first atomic theory 2100 years after Democritus claimed there was such a thing as an atom
Thomson's idea
Discovered the atom was divisible and had smaller, negatively charged particles (electrons)
Thompson's Plum Pudding Model
This model is where negatively charged particles are spread throughout positively charged material
Rutherford's Model
He proposed there was a dense, positively charged center to an atom, which he called the nucleus
Bohr's model
Electrons move in specific orbits around the nucleus of the atom
Subatomic Particles
Particles that are smaller than an atom (you should know 3: proton, neutron and electron)
Nucleus
The center of an atom
Proton
A positively charged particle found in the nucleus
Atomic Mass Unit (amu)
The mass of a subatomic particle (a proton has an amu of 1)
Neutron
Electrically neutral particle in the nucleus
Atomic Number
Determines the number of protons in the nucleus of an atom
Isotopes
Atoms of the same element with different numbers of neutrons, but the same number of protons (the proton number never changes)
Mass Number
Sum of the protons and neutrons in the nucleus
Atomic Mass
The average of all the isotopes of that element as they appear in nature (precisely why this is generally not a whole number, but a decimal)
Electrons
Negatively charged particles surrounding the nucleus
Electron Cloud
Space in which the electrons are likely to be found
Energy levels
Levels in which electrons are arranged. (first, second and third levels hold 2, 8 and 18 electrons; in that order)
Quark
An even smaller particle that makes up the subatomic particles in the nucleus. (It is said they are found in combinations of three)
Electromagnetic Force
Can attract or repel the particles it is acting on. (Electrons are kept in orbit around the nucleus due to this force)
Strong Force
Opposes the electromagnetic force and keeps the protons together. Works only when protons are very close together.
Weak Force
Responsible for Radioactive Decay (where a neutron in the nucleus changes into a proton and an electron) Key to the power of the sun.
Gravity
Weakest force in nature. It is the force of attraction exerted between all objects in nature. Most easily observed on large objects.