Agenda: September 25Agenda: September 25

1.1. Practice Problems: Problems 21-35 Practice Problems: Problems 21-35 odd, page 75 (These come from a odd, page 75 (These come from a different textbook.)different textbook.)

2.2. Introduction to River LabIntroduction to River Lab

3.3. Go back to your lab station to meet with Go back to your lab station to meet with your group.your group.

Practice ProblemsPractice Problems

21. 21. Certain elements have special affinities for other Certain elements have special affinities for other elements. This causes them to bind together in elements. This causes them to bind together in special ways to form __________.special ways to form __________.

23. The composition of a given pure compound is 23. The composition of a given pure compound is always ____________ no matter what the source always ____________ no matter what the source of the compound.of the compound.

COMPOUNDS

THE SAME

25. Give definitions for the terms 25. Give definitions for the terms pure substancepure substance and and mixturemixture. Give five examples of each. Give five examples of each

Pure SubstancePure Substance

Definition: Cannot be broken Definition: Cannot be broken down into smaller substances down into smaller substances AND still displace the AND still displace the properties of that substance.properties of that substance.

Examples: Any element on the Examples: Any element on the Periodic Table, and any Periodic Table, and any compound that is not mixed compound that is not mixed with other substances.with other substances.

Fe, Na, Mg, Zn, Au, Ag, C, CuFe, Na, Mg, Zn, Au, Ag, C, Cu

NaCl, HNaCl, H22O, COO, CO22, C, C1212HH2222OO1111

MixtureMixture

Definition: A physical combination Definition: A physical combination of pure substances.of pure substances.

Example: Can be homogeneous or Example: Can be homogeneous or heterogeneous mixtures.heterogeneous mixtures.

Oil and Water (Heterogeneous), Oil and Water (Heterogeneous),

Sugar in Hot Tea (Homogeneous), Sugar in Hot Tea (Homogeneous),

Steel (Metal Alloy), Steel (Metal Alloy),

Chocolate Chip Cookies Chocolate Chip Cookies (Heterogeneous)(Heterogeneous)

27.27. What does it means to say that a solution What does it means to say that a solution is a homogeneous mixture?is a homogeneous mixture?

The entire solution looks the same throughout. You can not tell The entire solution looks the same throughout. You can not tell one substance from another. This can be either liquids solutions, one substance from another. This can be either liquids solutions, solid solutions (alloys), or gas solutions.solid solutions (alloys), or gas solutions.

LIQUIDLIQUID SOLIDSOLID GASGAS

29. 29. Classify the following as mixtures or pure Classify the following as mixtures or pure substances:substances:

a)a) The air you are breathing =The air you are breathing =

b)b) The soda you were drinking at home =The soda you were drinking at home =

c)c) The water that comes through your pipes The water that comes through your pipes to water the lawn = to water the lawn =

d)d) The diamonds in Mrs. N’s wedding ring = The diamonds in Mrs. N’s wedding ring =

MIXTURE

MIXTURE

MIXTURE

PURETHE ELEMENT CARBON

31. 31. Classify the following mixtures as Classify the following mixtures as heterogeneous heterogeneous oror homogeneous: homogeneous:

a)a) SoilSoil

b)b) MayonnaiseMayonnaise

c)c) Italian Salad DressingItalian Salad Dressing

d)d) Wood DeskWood Desk

e)e) Sand at the BeachSand at the Beach

HOMOGENEOUS

HOMOGENEOUS

HETEROGENEOUS

HETEROGENEOUS

EITHER, DEPENDS ON THE SAND

Polluted River LabPolluted River LabWater Testing Team Challenge (Period 1)Water Testing Team Challenge (Period 1)

Team 1: Team 1: Tree Huggers Tree Huggers IncorporatedIncorporated

Group 1: Group 1: Tolle & Tori are Tolle & Tori are Testing Sample A at Lab Testing Sample A at Lab Station 1 Station 1

Group 2:Group 2: Liz & Sophia are Liz & Sophia are Testing Sample B at Lab Testing Sample B at Lab Station 2Station 2

Group 3: Group 3: Linda & Alhana Linda & Alhana are Testing Sample C at are Testing Sample C at Lab Station 3Lab Station 3

Team 2: Team 2: Big-Foot Big-Foot

Protection Protection AgencyAgency

Group 4: Group 4: Dominick & Dominick & Andreana are Testing Andreana are Testing Sample A at Lab Sample A at Lab Station 4 Station 4

Group 5:Group 5: Ashley & Ashley & Robbin are Testing Robbin are Testing Sample B at Lab Sample B at Lab Station 5Station 5

Group 6: Group 6: Dustin & Josh Dustin & Josh are Testing Sample C are Testing Sample C at Lab Station 6at Lab Station 6

Team 3: Team 3: Park Ranger Park Ranger

Genius Genius SquadSquad

Group 7: Ben & Aaron Group 7: Ben & Aaron are Testing Sample A are Testing Sample A at Lab Station 7at Lab Station 7

Group 8: Group 8: Gloria & Gloria & Bernice are Testing Bernice are Testing Sample B at Lab Sample B at Lab Station 8 Station 8

Group 9:Group 9: Eric & Jake Eric & Jake are Testing Sample C are Testing Sample C at Lab Station 9at Lab Station 9

Team 4: Team 4: Mother Earth Mother Earth MissionariesMissionaries

Group 11: ____ are Testing Group 11: ____ are Testing Sample A at Lab Station 11Sample A at Lab Station 11

Group 12: Group 12: ___ are Testing ___ are Testing Sample B at Lab Station 12 Sample B at Lab Station 12

Group 13:Group 13: ___ are Testing ___ are Testing Sample C at Lab Station 13Sample C at Lab Station 13

Group 14: Group 14: ____ are Testing ____ are Testing Sample C at Lab Station 14Sample C at Lab Station 14

Local River MapLocal River Map

Site C

Site A

Site B

Down Stream

Down Stream

Up Stream

HypothesisHypothesis

If a soluble salt can be If a soluble salt can be removed from non-removed from non-soluble sand and the soluble sand and the percentage (by mass) of percentage (by mass) of salt in the mixture can be salt in the mixture can be determined, then it can determined, then it can be determined if the be determined if the filters at the plant need to filters at the plant need to be changed.be changed.

Your Team AssignmentYour Team Assignment

Each group will test a sample from one of the sites.Each group will test a sample from one of the sites.

If ANY of the downstream sites result in a percentage of If ANY of the downstream sites result in a percentage of greater than 20% salt from the sandbar mixture, then your greater than 20% salt from the sandbar mixture, then your team MUST recommend that the company should replace team MUST recommend that the company should replace the filters. the filters. The cost is worth it in order to protect the The cost is worth it in order to protect the environment.environment.

If the downstream sites have less than 20% salt in the If the downstream sites have less than 20% salt in the sandbar mixture, then you can recommend to the sandbar mixture, then you can recommend to the company that they do not need to change their filters.company that they do not need to change their filters.

Practice CalculationsPractice Calculations

The mass of the weighing cup is 1.34 gramsThe mass of the weighing cup is 1.34 grams

The mass of the sand/salt sandbar sample + The mass of the sand/salt sandbar sample + cup is 3.48 gramscup is 3.48 grams

The mass of the 250 mL beaker + the mass of The mass of the 250 mL beaker + the mass of the watchglass is 367.12 gramsthe watchglass is 367.12 grams

The mass of the beaker, watchglass and The mass of the beaker, watchglass and polluting salts is 368.32 gramspolluting salts is 368.32 grams

What is the percent pollution in the sample?What is the percent pollution in the sample?