Chapter 3: Matter—Properties and Changes Section 3.4 Types of Matter Elements & Compounds
What is matter?• Anything that has mass and takes up space• Mass is a measurement of the amount of matter in an object. It is different than weight which measures the amount of matter AND the gravitational pull on an object.
Now that you’re an expert, which of thefollowing is matter? Matter Not 1. A book Matter 2. A house 3. A thought 4. Your brain 5. Light 6. Your cell phone 7. Radio waves
There is so many different kinds of matter, that we need to organize it. Substances have a uniform and unchanging composition examples: salt, water, sugar
Chemical symbols• Make it easy to write the formulas for chemical compounds• Ex: salt water NaCl H 2O
Elements• A pure substance that cannot be broken down into simpler substances by physical or chemical means• 91 naturally occurring elements• Symbolized by one capital letter or one capital letter and 1 lower case – ex: S = sulfur – Na = sodium• In mid 1800’s, no chart for organizing the elements that were known at the time
Dmitri Mendeleev--1869-Organized the knownelements into a table ofrows and columns basedon their similarities andmasses.
Periodic table• Organized into horizontal rows called periods and vertical columns called families• Called “periodic” because properties of elements repeat as you move from period to period• Mendeleev’s table left blank spaces for elements yet to be discovered and predicted their properties
Compounds• A combination of 2 or more different elements that are combined chemically• Most of the matter in the universe are compounds• Ex: water (H2O), sugar (C12H22O11), salt (NaCl), aspirin (C9H8O4)
Compounds• Can be broken down into simpler substances by chemical means• Usually requires energy
Compounds• Properties of a compound are different from its component elements• Ex: water—liquid at room temp. Hydrogen—a colorless, tasteless gas Oxygen—a colorless, tasteless gas
Sodium chloride• As a compound, it is a white, unreactive solid that adds flavor to food• Its component elements:Chlorine—poisonous, pale,green gas Sodium—a highly reactive element that fizzes in water
States of MatterClassification based upon the following: Particle arrangement Energy of particles Distance between particlesState of matter is dependent on temperature and pressure of the surroundings
Physical Properties of Matter A characteristic that can be observed or measured without changing the composition of the sample Properties such as density, color, odor, taste, hardness, melting point, boiling point
Physical Properties of Matter: Two Types1. Extensive: dependent on the amount of substance present --length, volume2. Intensive: independent of the amount of substance present --density, melting point, boiling point --used to identify substances
Chemical Properties Ability or inability of a substance to combine with or change into one or more other substances
Physical Chemical Properties Properties• Conducts electricity • Forms dark blue• Malleable solution with• Ductile ammonia• Reddish brown • Forms green• Shiny compound when exposed to air• Density = 8.92 g/cm 3• Melting pt = 1085°C• Boiling pt = 2570°C
Classify each as a physical or chemical property:1. Iron and oxygen form rust.2. Iron is more dense than aluminum3. Magnesium burns brightly when ignited.4. Oil and water do not mix.5. Mercury melts at -39°C.
Law of Conservation of MassMass is neither created nor destroyed during a chemical reaction—it is conserved. (Antoine Lavoisier) Mass of reactants = Mass of products
Antoine Lavoisier—aFrench scientisto 1743-1794o Father of ModernChemistryo One of the first to usean analytical balance
When you burn a big pile of wood, why doyou only end up with a tiny pile of ashes?
In an experiment, 10.00 g of red mercury (II) oxidepowder is placed in an open flask and heated until itis converted to liquid mercury and oxygen gas. The liquid mercury has a mass of 9.26 g. What is the mass of oxygen formed in the reaction?
Law of Multiple Proportions• When different compounds are formed using the same elements, different masses of one element combine with the same relative mass of the other element in small, whole number ratios.