CHAPTER 2 DESCRIBING MATTER SECTION 1

Matter-anything that has mass and takes up space. Properties of Matter -Matter can have many different properties or characteristics -Chemistry is the study of the properties of matter and how it changes

- Substance-a single kind of matter that is pure, meaning it always has a specific makeup- or composition- and a specific set of properties. -Every form of matter has two kinds of properties- physical and chemical properties.

- Physical Property- a characteristic of a pure substance that can be observed without changing it into another substance. -Examples of physical properties -Density, Hardness, Texture, Color, State (solid, liquid, gas) -Ability to dissolve in water, conductivity, malleability

-Chemical Property- a characteristic of a pure substance that describes its ability to change into different substances. -To observe a chem. prop. you must try to change it. -Examples of chemical properties -Flammability, Ability to react with oxygen (rust or tarnish)

What is an Element: -All matter in the universe is made of slightly more then 100 different substances called elements. -Element-a pure substance that cannot be broken down into any other substance by physical or chemical means. -Elements are the simplest substances

Particles of Elements- Atoms -All matter is made of atoms -Atom-is the basic particle from which all elements are made. -Different elements have different properties because their atoms are different.

Separating Mixtures: -Mixtures can be separated into their component parts since they are not chemically combined. -Sometimes it may be difficult but it can be done. -Ways to separate mixtures -magnets, filters, distilling, and evaporating

When Atoms Combine: -Atoms of different elements can combine. -Atoms combine to form larger particles named molecules -When atoms combine to form molecules they are connected by chemical bonds, which is the force of attraction between 2 atoms -Example of a molecule versus an atom H 2 O is made of 3 atoms (2 hydrogen and 1 oxygen atom bonded together to form 1 water molecule)

Compounds: -All matter is made of elements but most are not alone in nature. -Compound-a pure substance made of two or more elements chemically combined in a set ratio. -A compound can be represented by chemical formula ex: H 2 O or CO 2 -When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements.

Mixtures- made of two or more substances, elements or compounds, that are together in the same place but are not chemically combined. -Each substance keeps it’s properties in a mixture -Mixtures don’t have to be uniform

Types of Mixtures -Heterogeneous Mixture- a mixture in which pure substances are unevenly distributed throughout the mixture.

-Homogeneous Mixture -a mixture in which substances are evenly distributed throughout the mixture. -You can’t see the parts of a homogeneous mixture

-Solution-a homogeneous mixture in which one substance dissolves in another. -Solvent-does the dissolving (ex: water) -Solute-disappears or is dissolved (ex:sugar )

Separating Mixtures -Mixtures can be separated into their component parts since they are not chemically combined. -Sometimes it may be difficult but it can be done. -Ways to separate mixtures -magnets, filters, distilling, and evaporating

CHAPTER 2 SECTION 2

Separating Mixtures: -Mixtures can be separated into their component parts since they are not chemically combined. -Sometimes it may be difficult but it can be done. -Ways to separate mixtures -magnets, filters, distilling, and evaporating

Changes of State: -States of matter are solids, liquids, and gases. -A change in state is an example of a physical change

Changes in Shape or Form: -Solutions, where one substance dissolves in another, are an example of a physical change. -Other examples: Bending, crushing, breaking, chopping, and anything else that changes form or shape. -You can separate mixtures by filtering and distilling

Chemical Change- a change in matter that produces one or more new substances -A chem. change produces new substances with properties different from those of the original substances

Examples of Chemical Changes: -Methane, CH 4, when combined with oxygen by combustion, forms CO 2 and water vapor. -Other chemical changes are electrolysis, oxidation, and tarnishing. -See chart on Page 70 in book.

. Conservation of Matter: -Law of conservation of matter- the principle that the total amount of matter is neither created nor destroyed during any physical or chemical change. -“What goes in must come out!!” -The mass of the reactants must equal the mass of the products. -The number of atoms in = number of atoms out

ENERGY The ability to do work or cause change. Every chemical or physical change requires energy. EX. Bending a paper clip

FORMS OF ENERGY Temperature - a measure of the average energy of random particles of matter Thermal energy - the total energy of all the particles in an object Endothermic change- energy is taken in ex. Ice melting

Exothermic change- energy is released ex. Combustion recall whoosh lab Chemical Energy- energy stored between chemical bonds between atoms

Electromagnetic energy- a from of energy that travels through space as waves. Ex radio waves, x-rays Electrical energy- the energy of electrically charged particles moving from one place to another ex. electric pickle