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Chapter 2
Matter & Change
Matter
Anything that has mass & takes up spaceAll materials you hold or touch
Air you breathe
Mass = a measure of the amount of matter an object contains
Volume = measure of the space occupied by an object
Substance = type of matter with a fixed composition (can be an element or a compound)
Physical Properties
Quality or condition of a substance that can be observed or measured without changing the substances composition
color, shape, odor, texture, density
Intensive Properties
Physical properties depend upon the type of matter in a sample, not the amount, it helps you determine what a substance is Melting point, Density, Viscosity, Color
Every sample of a given substance has the identical intensive properties because every sample has the same composition
Extensive Properties
Physical properties that depend upon the amount of matter in a sample on hand & do not help you determine what a substance is Mass Length Volume
This blue crystal has a mass of 0.32g and a density of 3.20 g/cm3.It is not malleable and has a volume of 0.1 cm3
Which properties listed are intensive?3.2 g/cm3, not malleable, blue
Which properties listed are extensive?0.32g, 0.1cm3
States of Matter: Solid
Particles are in a fixed position – therefore, they have a rigid structure
Particles have almost no freedom to change position; they change position around a fixed point
Not easily compressed
States of Matter: Liquid
Particles are close together and move freely around each other
Liquids vary in viscosity (the resistance of a fluid to flow – thickness)
molasses vs. vinegar Not easily compressed
States of Matter: Gas
Particles expand to fill available space, move constantly and rarely stick together
Gas exerts pressure (force exerted per unit area of a surface) and will escape its container if possible – balloons, propane tanks, gas grills
Easily compressed
Physical Changes
Properties of a material change; however, the composition of the material does not change
Can be reversible Melting, boiling
Can be Irreversible Slicing, cutting
Mixtures
Mixture a combination of two or more components
Hetero vs. Homogeneous
Homogeneous mixture = contains two or more gases, liquids, or solids that are blended evenly throughoutVinegar, salt water, margarine,
gasoline Heterogeneous mixture = a mixture in which different materials can be distinguished easilyFruit salad, trail mix, granite
Which is which?
Heterogeneous Homogeneous
P
Separating Mixtures
Filtration = separates a solid from the liquid in a heterogeneous mixture
Distillation = process used to separate dissolved solids from a liquid (boiling and then condensing)
Evaporation
Substance
Matter that has a uniform and definite composition
Every sample has identical intensive properties because every sample has the same composition
Elements and Compounds
Compound two or more elements that are chemically combined, can be broken down into simpler substances
Water Hydrogen & Oxygen Element substance that cannot be broken down into simpler substances composed of one type of atom
Chemical Properties of Matter
The way a substance reacts with another to form a new substance with different properties
Involve reactivity – ability of a substance to combine chemically with another substance
Chemical properties of compounds vary from the individual elements that they are made from
Chemical Changes
Chemical changes are changes in composition – atoms are changed or rearranged
bumper with rust
Law of Conservation of Mass
Mass can not be created or destroyed
Total mass of all matter stays the same as before the change – it changes from one form to another
From ice to liquid to gas, it will all have the same mass
Molecules
Molecule smallest unit of a substance that exhibits all of the properties characteristic of that substance
Chemical Formula
Chemical shorthand that uses symbols and numbers indicating the elements in a compound and their ratios
C6H8N4O2 Theobromine (chocolate)
C6H12O6 Fructose (sugar)
The End