1. Ch. 2 Matter and Change

2. 2.1 Properties of Matter Describing Matter
Extensive Properties: depend on amount of matter in a sample
Mass: amount of matter
Volume: space occupied
Intensive Properties: depend on type of matter, not amount
Density: mass/volume
Absorbancy
Substance: uniform and definite composition (same stuff throughout and in any sample)
Physical property: can be observed or measured without changing composition of the substance

3. States of Matter: solid, liquid, gas, plasma
Solid: definite shape and volume
Particles packed together, vibrating in place
Liquid: no definite shape but definite volume
Particles flow around each other but stay associated
Gas: no definite shape or volume
Particles dissociate; easily compressed into smaller volume
Vapor: gas state of a substance that is usually liquid or solid at room temperature

4. 2.2 Mixtures Mixture: a physical blend of 2+ components
Heterogeneous mixture: composition is not uniform
Clumps of substances, i.e. chili, iced tea, salad dressing
Homogeneous mixture (solution): uniform composition
Completely mixed, i.e. air, salt water, stainless steel
Phase: part of a sample with uniform composition and properties
Heterogeneous mixtures have at least 2 phases
Homogeneous mixtures have one phase

5. Separating Mixtures Use differences in physical properties
Filtration: separate a solid from a liquid
Distillation: boil a liquid solution, catch and condense the vapor
Uses the differences in boiling points of different substances to separate one liquid from another

7. 2.2 Lesson Check
Classify each of the following as a homogeneous or heterogeneous mixture:
Food coloring
Ice cubes in liquid water
Mouth wash
Mashed, unpeeled potatoes
In general, when would you use filtration to separate a mixture? Distillation?
List 5 items that fit in each of the following categories:
Substance
Homogeneous mixture
Heterogeneous mixture
Solution

8. 2.3 Elements and Compounds
Element: simplest form of matter with unique set of properties (see periodic table)
Cannot be broken down into simpler substances by chemical means
Compound: substance with 2+ elements chemically combined in fixed proportions
Can be broken down into simpler substances by chemical means
Chemical change: produces matter with a different composition than the original matter
Heating
Electricity
Burning
Chemical reactions

9. Symbols and Formulas Chemical Symbols are used to represent elements
Na, H, C, Au, Pb, F
Chemical formulas represent compounds
NaCl, H2O, KMgO4, CO2, NaOH

10. Periodic Table Arranges elements based on repeating properties
Periods: horizontal rows
Groups: vertical columns, elements in groups have similar physical and chemical properties

11. 2.4 Chemical Reactions
Chemical property: the ability of a substance to undergo a specific chemical change
Chemical changes always change the composition of matter
Substances present at the start of a reaction are called reactants
Substances produced in the reaction are called products
A + B  AB
CD  C + D
E + FG  EF + G
HI + JK  HK + JI

12. Recognizing Chemical Changes
Energy transfer
Change in color
Gas production
Precipitate formation

13. Conservation of Mass
In any physical change or chemical reaction mass of the reactants = mass of products
In chemical reactions mass cannot be created or destroyed
Observable in closed systems