Notes

Introduction to Chemistry pages 45-75 Read page 73 (Five facts.)

(Group questions)

List 6 types of solutions systems and give an example of each. P. 69

List and describe five methods of separating Mixtures. P.70-72

    States of matter - matter that exists naturally on Earth can be distinguished by its properties

    Solid - a form of matter that has its own definite shape and volume

    Liquid - a form of matter that flows, has constant volume, and takes the shape of its container.   changing shape and definite volume

Gas - a form of matter that not only flows to conform to the shape of its container but also fills the entire volume of its container.  changing shape and changing volume

*Plasma-Molten mass with a charge.(Usually found in stars.)

Vapor - the gaseous state of a substance that is solid or a liquid at room temperature

Physical property - a characteristic of matter that can be observed or measured without changing the sample’s composition

Extensive properties - properties that are dependent on the amount of substance present

intensive property - properties that are independent of the amount of substance present

Chemical property - the ability or inability of a substance to combine with or change into one or more other substances. Can only be measured by changing the sample.

Physical change - a change which alters a substance without changing its composition

Phase change - a transition of matter from one state to another

Chemical change - a process that involves one or more substances changing into new substances

Law of conservation of mass - states that mass is neither created nor destroyed during a chemical reaction - it is conserved 

.( Matter is neither created nor destroyed, it is only   in form.)

*Law of conservation of energy=  Energy is not created or destroyed but it is converted from one form to another. ( Energy is neither created nor destroyed, it is only   in form.)

*Law of conservation of energy and matter= 

Energy and matter are NOT created or destroyed, but converted from one form to another.

( Energy and matter is neither created nor destroyed, it is only     from one to another.)

E=mc2

Element - a pure substance that cannot be separated into simpler substances by physical or chemical means

Periodic table - organizes the elements into a grid of horizontal rows called periods and vertical columns called groups or families

Compound - made up of two or more different elements that are combined chemically in a fixed ratio

Law of definite proportions - states that a compound is always composed of the same elements in the same proportion by mass, no matter how large or small the sample.(Usually formula units.)

(Compounds always have the same ratio of elements.)

Percent by mass - the ratio of the mass of each element to the total mass of the compound expressed as a percentage

Law of multiple proportions - states that when different compounds are formed by a combination of the same elements, different masses of one element combine with the same fixed mass of the other element in a ratio of small whole numbers.

Atoms can combine in more than one ratio.(Usually Molecules)

CO, CO2, CO3-2

Mixture - a combination of two or more pure substances in which each pure substance retains its substance retains its individual chemical properties

heterogeneous mixture - a mixture that does not blend smoothly throughout and in which the individual substances remain distinct The mixture is NOT uniform throughout.

homogeneous mixture - a mixture that has constant composition throughout; it always has a single phase

The mixture is uniform throughout.

*Alloys-

Mixture of a metal and one or more other substance(s).

*The three main divisions of mixtures.

A) Solution-

A homogenous mixture.(Particles dissolve.)

B) *Suspension-

Mixtures with large particles that settle out over time.

C) *Colloid-

   Mixtures with mid-sized particles that do not settle out.

(Colloids exhibit the tyndall effect)

*Tyndall effect-

This is the process in which light scatters.

Solutions - a homogeneous mixture

Filtration - a technique that uses a porous barrier to separate a solid from a liquid

Distillation - a physical separation technique that is based on differences in the boiling points of the substances involved

Sublimation - the process during which a solid changes to vapor without melting

Chromatography - a technique that separates the components of a mixture dissolved in either a gas or a liquid based on the ability of each component to travel or to be drawn across the surface of a fixed substrate

Crystallization - a separation technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance

Chemical reactions usually give off visual signs.

Some may include:

Bubbles, color change, fire, light, steam, change in appearance/state of matter.

Element-

Substance composed of only one type of atom.(Not chemically combined.)

*Draw the “stair steps”

Metals below and to the left.

Nonmetals above and to the right.

Metalloids touching the steps, except Aluminum.

*Diatomic Molecules-

Substances that are composed of two atoms of the same kind that are chemically combined.

*Hydrogen and the shape of the number “7”.

Hydrogen(H2), Nitrogen(N2), Oxygen(O2), Chlorine(Cl2), Bromine(Br2), Fluorine(F2), Iodine(I2), and sometimes Astatine.

*Percent error=

Expresses the accuracy based on 100.

Percent error=   __|error|_____ *100

                      Accepted value

Ex. Calculate the % error if the student obtained 22 g and the accepted value(Theo. value) was 20 g.

Percent error=|22 g-20 g |*100= 10 %

                        20 g

Per. by mass= Mass of element(100)

                                                                     Mass of compound

Ex. Calculate the mass of each element in the following compound:

C6H12O6

         Mass X subscript

C= 12 g/mole(6)=72 g/mole   72/180(100)=40%

H= 1 g/mole(12)=12 g/mole   12/180(100)=6.7%

O=16 g/mole(6)=96 g/mole 96/180(100)=53.3%

Total mass =180 g/mole

Ex. Calculate the mass of the hydrated and dehydrated samples.

C6H12O6 .5 H2O

         Mass X subscript

C= 12 g/mole(6)=72 g/mole  

H= 1 g/mole(12)=12 g/mole    

O=16 g/mole(6)=96 g/mole  

Total mass =180 g/mole

Hydrated mass   (.5 H2O)

H= 1 g/mole(10)=10 g/mole    

O=16 g/mole(5)= 80 g/mole  

Total                              90 g/mole

Or Water has a mass of 18 g/mole(2 for H and 16 for Oxygen)

5 moles(18 g/mole)=90 g/mole

Molecule mass + water mass=Hydrated mass

180 g/mole  +  90 g/mole= 270 g/mole

Dehydrated mass is only the molecule, not the water.