Mrs. Kundrat

During labs you MUST wear goggles.  No goggles, no lab.  No lab, no credit.

Chemistry  study of composition, structure and properties of matter and  the transformations that matter undergoes.

Matter  Anything that has mass and takes up space.

Mass Weight  The quantity of matter in an object.  The gravitational pull on the matter in an object. = mass x g

Branches of Chemistry BranchArea of EmphasisExamples Organic chemistry most carbon-containing chemicals pharmaceuticals, plastics Inorganic chemistry in general, matter that does not contain carbon minerals, metals and nonmetals, semi-conductors Physical chemistry the behavior and changes of matter and the related energy changes reaction rates, reaction mechanisms Analytical chemistry components and composition of substances food nutrients, quality control Biochemistrymatter and processes of living organisms metabolism, fermentation

Technology:  Applications of science.

Scientific Method:  A systematic approach used in studying the natural world.

Qualitative Data Quantitative Data  Something you observe.  Data that’s measured

Scientific Method  observation  hypothesis  experiment  conclusion

Scientific Law  A statement about something that happens in nature

Scientific Theory  An explanation about why or how something occurs.

A variable is a factor that is “varied” during the experiment. It can have more than a single value. Change only one variable at a time. Variables

Independent variable – you control or change it during the experiment Dependent variable - changes as a result of changes in independent variable Constant – factors that do not change Control – a standard of comparison

Review #1  What is a common way to test a hypothesis?

#1  To perform an experiment

Review #2 Which of the following has conditions that are kept the same? a) standard b) independent variable c) dependent variable d) control

#2  D) a control has conditions that are kept the same.

Review #3 What is used as a model to compare the variable to? a) standard b) variable c) unit d) control

#3  A) standard

Review #4  A scientific is an observation of what occurs in nature. A scientific is an explanation

#4  A scientific law is an observation of what occurs in nature. A scientific theory is an explanation.

Review #5  Mass is.  Weight is.  Matter is.

#5  Mass is amount of matter in an object.  Weight is mass x pull of gravity.  Matter is anything that has mass & space.

Lab Purpose: Design a paper airplane that will travel the greatest distance when thrown  Write a “formal” lab report on the back  Test the second model if there is enough time.

Substance b has definite uniform composition & properties b elements & compounds

Chemical Properties b characteristics that can be observed only by altering the identity b flammability, reactivity,....

Physical Properties b characteristics that can be observed without altering the identity b color, odor, boiling point, density,....

 Extensive Properties:  Extensive Properties: physical properties that depend on amount of a substance.  Intensive Properties:  Intensive Properties: physical properties that do NOT depend on quantity.

Physical States DensityShapeVolume Pressure effects Solid Liquid Gas Plasma High Low Definite of container Definite of container little great

Classify these as physical or chemical properties: Review: Classify these as physical or chemical properties:  density  reactivity  Color  Melting point

Classify these as physical or chemical properties: Review: Classify these as physical or chemical properties: p  Density- p c  Reactivity- c p  Color- p p  Melting point- p

Physical Change b does NOT alter the identity b only the arrangement of the particles with each other has changed

Chemical Change b alters the identity. b new substances are formed

Signs of Chemical Change b bubbles/ fizz (gas) b temp. change b color change b odor change b precipitate (solid)

Conservation of Mass b matter is not created nor destroyed b the total mass you begin with equals the total mass after the reaction Lavoisier

Review #1 b What type of change DOES alter the identity of a substance? Chemical

Review #2 b What type of change occurs when water turns into ice? Physical

Review #3 b When a sample of water was separated, it produced 10.0 g hydrogen and 79.4 g oxygen. How much water was in the sample? 89.4 grams

#3: 89.4 g water b 10.0 g hydrogen g oxygen = 89.4 g water

Problem  A 10.0 g sample of magnesium react with oxygen to form 16.6 g MgO. How many grams of oxygen reacted? 6.6 g

Physical or Chemical Changes?  Boil  Burn  Condense  Corrode  Crumple  Crush  Explode  Ferment  Freeze  Grind  Melt  Oxidize  Rot  Rust  Tarnish  Vaporize P P C P P P C C P C P C C C C P

Elements  the simplest forms of matter.  Cannot be separated into simpler forms by chemical reactions

Elements  all on Periodic table  represented by symbol of 1 or 2 letters (2nd letter is lower-case)

Compounds  can be separated into simpler substances by chemical means only  contains 2 or more different elements in fixed proportions.

Compounds chemical & physical properties are different from those of the elements silver + bromine = silver bromide

Formula  chemical symbols show the numbers of atoms of each element that make up a compound.  Subscripts following symbols show #’s of atoms. CompoundFormula CaffeineC 8 H 10 N 4 O 2

Atom? Molecule? … the smallest particle of an element that retains its identity. … the smallest particle of a compound that retains its identity.

Mixtures  A blend of two or more substances. The identity of each substance is not changed.  Mixtures do not have specific compositions.

Mixtures  can be separated into simpler substances by physical means

Heterogeneous Mixture  Is NOT uniform throughout

Homogeneous Mixture  is uniform throughout  also called a Solution  gas, liquid or solid phases

Separating Mixtures  Filtration  Chromatography  Distillation  Crystallization

Distillation – another example:

Separating Mixtures  Centrifuge  Magnet

What is removed in each step from a mixture of sugar, sand, iron, and water?

Review #1 Identify as (S) substance, (HM) homogeneous mix., or (HT) heterogeneous mix:  Alphabet soup  Salt  Concrete  Vegetable oil  Air  Paint  Sea water  Granite  Steel  Sugar

#1: (S)subs., (HM) homog.mix., (HT) hetero.mix:  Alph.soup -HT  Salt - S  Concrete - HT  Veg.oil - S  Air - HM  Paint - HT  SeaH 2 O-HM  Granite - HT  Steel - HM  Sugar - S

Review #2: Separating sand from water can be done by? Filtration

Review #3: Sugar in sugar water can be removed by? Crystallization

Review #4: The separation technique that takes advantage of different boiling points is? Distillation

Review #5: Removing chlorophyll pigment from leaves might be done by? Chromatography

Review #6: The best way to decompose water into oxygen and hydrogen is by? Electrolysis

Review #7: Crude oil is broken down by heat, vaporization, and condensation into various liquids. This process is called? Distillation

Review #8: Why is every solution a mixture, but not every mixture is a solution? Not all mixtures are homogeneous (= solution)

Review #9: How can you separate a mixture? Filtration, Distillation, Chromatography, Crystallization

Review #10: How can you separate a compound? Chemical means only

Review #11: How can you separate an element? Cannot – by chemical nor physical means

Review #12: What is the difference between an atom and element? An atom is the smallest particle of an element that retains its identity.

Lab notebooks:  Title  (Theory)  Purpose  Materials  Procedure (short)  Data/Observations  Calculations  Conclusions

Reminder:  Read labs completely and thoroughly before handing in. Make sure you’ve done all of it.  Show your work!

Chemical Reaction changes a substance(s) into a new substance(s) with different physical and chemical properties.

 Reactants: original substance(s)  Products: final substance(s)

Periods  the horizontal rows on the periodic table

Groups (Families)  the vertical columns on the periodic table

Noble Gases  this is the most stable type of atom.  It is found in group #18

 metals: left 2/3 of table  nonmetals: upper right side of table  semimetals: “stairstep” between metals & nonmetals

Metal Properties  have luster / shine  good conductors  usually exist as solids  malleable  ductile

Nonmetal Properties  no luster  poor conductors of heat & electricity  not malleable  not ductile

Semimetals (Metalloids)  properties are between those of metals and nonmetals  6 (to 8) semimetals (Po & At classifications vary)