Miss Wellers Chemclass
Terms
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- composition
- what matter is made of;
- properties
- what the matter is like; how matter behaves; earthquakes
- matter
- anything that has mass and volume
- mass
- the amount of matter in an object
- What does an object’s weight depend on?
-
how hard gravity pulls on it
this will vary, depending on location - An object’s mass does NOT
- no matter where it is.
- volume
- the amount of space an object occupies
- atom
- The most basic unit of matter
- molecule
- a neutral group of atoms held together by chemical bonds
- At the smallest level, all matter is composed
- of atoms.
- All matter can be classified as either
- a pure substance or a mixture.
- pure substance
- a type of matter for which all samples have the same properties; they behave exactly the same way
- there are 2 types of pure substances,
- elements and compounds.
- elements
- samples of a substance that contain only one type of atom
- An element CAN’T be broken down into simpler substances
- by chemical means.
- allotropes
- different forms of an element in the same physical s
- compound
- a substance made up of 2 or more different elements that are chemically combined
- Properties of Compounds
- every sample of a particular compound has the same properties as every other sample
- mixture
- a combo of 2 or more substances; each retains its individual properties
- In a mixture, there are no ______________between the different substances.
- Chemical bonds
- There are 2 types of mixtures
- homogeneous mixtures and heterogeneous mixtures
- homogeneous mixture
- all regions of a homogeneous mixture are identical in composition and properties
- Homogeneous mixtures are evenly-mixed, or uniformly distributed, at the particle level, and are also referred to as
- Solutions
- alloy
- a homogeneous mixture of 2 or more metals
- heterogeneous mixture
- some regions have different composition and properties than other regions
- In heterogeneous mixtures, although the particles may appear to be evenly mixed at the macroscopic level, they are NOT
- uniformly-distributed at the microscopic (particle) level.
- suspension
- appears uniform while stirred; settles when agitation stops
- colloid
- contains tiny particles that never settle out
- Physical Separation
- we say that we separate them physically (without chemical reactions),
- Magnet separates mixtures
- Physically
- Filter
- Physically
- Evaporation
- Physically
- Chromatography
- Physically
- Distillation
- Physically
- Centrifuge separates mixtures
- Physically
- density of a sample of matter is
- he quantity of mass of that substance that occupies one unit of vol.; density is a constant ratio of mass to volume
-
Formula for density:
(measures mass) - D= M/V
- units for density are always
- mass / volume units
- extensive properties
-
depend on the size of the sample
Examples: volume, weight, mass, heat content - intensive properties
-
DO NOT depend on the size of the sample
Examples: density, temperature, hardness, color - physical properties are
-
observed wo/changing the chem. composition of the matter
Examples: color, texture, mass, state of matter, melting point, elec. conductivity
ductility, malleability, luster - physical properties for metals
- ductility, malleability, luster
- chemical properties
-
hese describe how the substance reacts (or fails to react) with other substances to produce new substances
Examples: reactivity with acid, reactivity with oxygen (flammability) - physical change
- occurs when a physical property of a substance changes without any change in the substances chemical properties or composition