Matter… has mass and occupies space. Mass is the amount of matter an object contains. Mass never changes, but weight does.
The States of Matter Matter exists in three states: Solid: a rigid substance with a definite shape Liquid: has a definite volume but takes the shape of its container Gas: takes the shape and volume of its container
Matter can be classified as a mixture or a pure substance.
- O- Only one substance - Uniform and definite composition - All samples have identical physical properties - Two or more substances mixed together - Indefinite composition - Can be physically separated into pure substances
- Only one type of element - Cannot be chemically separated into simpler substances - More than one type of element chemically bonded together - Can be chemically separated into elements
Each element has a name and a symbol. The symbol usually consists of the first one or two letters of the element’s name. Sometimes the symbol is taken from the element’s original Latin or Greek name. Examples: oxygen O krypton Kr Examples: gold Au aurum lead Pb plumbum
Compounds Compounds are substances that contain two or more different types of elements.
In general, the properties of compounds are quite different from those of their component elements. Example: Table salt is NaCl (sodium + chlorine), while sodium (Na) is a soft metal that acts explosively with water and chlorine (Cl) is a pale yellow- green poisonous gas
- S- Solutions(one phase) - Looks the same throughout - Uniform composition - Evenly mixed - S- Suspensions(two phases) - Looks different throughout (chunks) - Not uniform in composition - Will usually settle over time
Physical Properties Any characteristic of a substance that can be observed or measured without changing the composition of the substance. Ex: density, viscosity, melting point, boiling point, taste, hardness, color, odor
Chemical Properties – describe a substance’s ability to change to a different substance. Ex. burning, rusting, decomposing, fermenting, exploding and corroding
Intensive property- does not depend on the size of the system or the amount of material in the system. Examples- temperature, color, hardness, melting point, pressure and density
Extensive property- directly proportional to the amount of material in the system. Examples- mass, volume, length and total charge
Physical Change A physical change involves a change in one or more physical properties but no change in composition. The original substance is still the same material.
Molding Bread Chewing apple Digesting apple Sparkler Dissolving Kool-Aid powder in water
Simplifying Mixtures and Compounds The separation of a mixture is a physical change (such as distillation, filtration). Breaking down a compound into simpler substances is a chemical change (such as decomposition).
Sample Problem – 1.3 Describe how a mixture of iron filings and aluminum filings can be separated. Is this process a physical or chemical change?
Sample Problem – 1.4 What physical properties could be used to separate a mixture of iron filings and salt?
Sample Problem – 1.5 State several physical or chemical properties that could be used to distinguish between each of the following pairs of substances. a. gasoline and water b. copper and silver c. water and salt water solution d. aluminum and steel
Law of Conservation of Mass Mass is neither created nor destroyed in a chemical or physical process. reactantsproducts
Mass reactants = Mass products “What goes in, must come out!” Mass of Reactants (before reaction) Mass of Products (after reaction) Reaction occurs Notice the mass before and after the reaction are the same.
Law of Conservation of Mass hydrogen + oxygen water How much water is produced when 4.8 grams of hydrogen reacts completely with 38.4 grams of oxygen? (Answer: 43.2 grams)