Matter in Our World

Matter Made up of atoms Atoms that are all the same make an element Every element has different types of atoms

Elements Element Symbol Hydrogen H Mg Oxygen O Br Sodium Na Nitrogen K Sulfur Iodine I Ca C Boron Chlorine Zn Iron Si Ag Neon

Matter When elements chemically combine they form compounds The same element can combine Different elements can combine Matter can be physically combined into mixtures Lots of elements in the same place Lots of compounds in the same place Combination of elements and compounds in the same place

Matter Elements, compounds, and molecules are all pure substances Matter also exists as mixtures Homogenous Mixtures that look the same throughout Substances are miscible Heterogeneous Mixtures that you can see the different substances in Substances are immiscible

Matter Chemical formulas are important for telling us what compounds are made of Sugar – C12H22O11 Carbon Hydrogen Oxygen 22 atoms 11 atoms 12 atoms

Common Compounds Salt = NaCl Ammonia = NH3 Baking Soda = NaHCO3 Water = H2O Hydrogen Peroxide = H2O2 Bleach = NaOCl Glass = SiO2 Vinegar = CH3COOH

Kinetic Theory Three main points All matter is made of atoms and molecules These atoms and molecules are always in motion At high temperatures, particles move faster At the same temperature, larger atoms and molecules move slower than smaller ones

Kinetic Theory Used to describe the states of matter Changing States Solid Liquid Gas Changing States

Solid Atoms move very, very slowly Set volume Set shape States of Matter

Liquid Atoms move around Set volume Changing shape Can look at viscosity High viscosity = less flowing States of Matter

Gas Atoms move very, very fast Changing volume Changing shape Exerts pressure on objects High pressure = lots of movement States of Matter

Changing States of Matter Energy makes this happen Red Energy added Blue Energy taken away

Changing States of Matter Total amount of matter never changes Law of conservation of mass Total amount of energy never changes Law of conservation of energy

Changes in Matter Chemical change Physical change Changes the make-up of matter Different matter is made Physical change Does not change the make-up of matter Same matter exists – just a different form

Clues to Chemical Change Change in color Production of gas Production of a solid Key words: Burn, decay, ‘die’, ripen, rot

Clues to Physical Change Key words Cut, tear, melt, freeze, dissolve, grind

Properties of Matter Chemical Properties Only seen during chemical changes Describes how a substance reacts Reactivity How easily one substance can form another substance Examples: flammability, reactivity, ability to tarnish, ability to decay

Properties of Matter Physical Properties Can be seen without changing the object The same no matter how large or small the object is Examples: melting point, boiling point, color, density, smoothness

Density Amount of mass within a certain amount on space Mass Density = Volume Mass =

Density What is the density of a 0.996 g piece of graphite with a volume of 0.44 cm3? 2.26 g/cm3

Density A copper penny has a mass of 3.1 g and a volume of 0.35 cm3. What is the density of the penny? 8.86 g/cm3

Density A bar of sliver has a mass of 68.0 g and a volume of 6.48 cm3. What is the density of silver? 10.49 g/cm3

Density Sugar has a density of 1.59 g/cm3. What mass of sugar fits into a 140 cm3 bowl? 222.6 g

Density The density of silver is 10.5 g/cm3. A bracelet made of silver has a volume of 1.12 cm3. What is the bracelet’s mass? 11.76 g

Density Boron has a density of 2.34 g/cm3. What is the volume of 14.8 g of boron? 6.32 cm3

Density Mercury has a density of 13.5 g/cm3. What is the volume of 4.62 g of mercury? 0.34 cm3

Density The density of oak is generally 0.7 g/cm3. If a 35 cm3 piece of wood has a mass of 25 g, is the wood likely to be oak? 0.71 g/cm3