APES2017-18SummerAssignment

DearStudents, WelcometoAPEnvironmentalScience,alsoknownasAPES!Tobeginourstudyoflocal,regionalandglobalenvironmentalissues,Ihavepreparedachallengingyetengagingsummerassignmentforyou.Whenourschoolyearbeginswewillcontinuetoexaminenaturalandhumaninducedenvironmentalproblems.ThesummerassignmentisdueontheDirstdayofschool.Bepreparedforatestonthismaterial.AstudyguidewillbepostedonHaikuduringthesummer.Also,beforeschoolisout,stopbyandsignupforWhatAppgrouptocommunicateoverthesummer.

1.MathReview A.Completethemathreviewproblemworksheet.Allanswerswithworkshownona

separatepaper.

B.ReadCHSRdocumentregardingppm/ppb.Completetheproblemset.

2.EcologicalFootprintAnenvironmentallyawarecitizen,isawareoftheissuesaroundthemandtheirown

personalimpactontheearthanditsenvironments.Youwillbemeasuringyourimpact-or

footprint-ontheenvironmentbyfollowingthedirectionsbelow.

Createanewdocument.TitleitEcologicalFootprint.

A. Waterusagecalculator

Gotothelinkbelow.Calculateyourwaterusagefootprint.Takeascreenshotofyourresults

andpasteontoyourdocument.

http://www.gracelinks.org/1408/water-footprint-calculator

B.CarbonFootprintcalculator

Gotothelinkbelow.Calculateyourcarbonfootprint.Takeascreenshotofyourresultsand

pasteontoyourdocument.

http://www.nature.org/greenliving/carboncalculator/index.htm

C.EcologicalFootprintcalculator.Takeascreenshotofyourresultsandpasteontoyour

document.

http://www.footprintnetwork.org/resources/footprint-calculator/

Writeanessayanalyzingyourresults.IncludeacleardeSinitionofwhatanecological

footprintis.Analyzeyourwateruse,carbonandecologicalfootprintresults.Wereyour

resultsaboveorbelowthenationalaverage.Wereyousurprisedwithyourresults?What

arestepsyoucantaketomakelessofanimpactontheenvironment?BespeciSic.

3.EnvironmentalLaw’sTimelineCreateatimelineofthefollowingimportantevents,people,andlawsinenvironmental

science.Youcanbecreativeonhowyoucreateyourtimeline.Keynote,booklet,actualtime

lineformat(severalpapersattachedtougher),iMovieareallacceptableformsfor

submission.

Foreachitem,describeeachevent,personorlawinoneortwosentences.Makesure

everythingisinyourownwords.Learntheinformation.Thiswillbeonyourtest.Include

manydiagramsonyourtimeline.

*10,000yearsago:Agriculturalrevolution *275yearsago:Industrialrevolution *1854:WaldenbyHenryDavidThoreau *1862:HomesteadAct *1872:YellowstoneNationalParkfounded *1875:AmericanForestryAssociationfounded *1890:YosemiteplusSequoiaNationalParkfounded *1838:JohnMuir *1891:GeneralRevisionAct *1892:SierraClubfounded *1900:LaceyAct

*1901-09:GoldenAgeofConservation(TheodoreRoosevelt) *1903:Firstnationalwildliferefugeestablished *1905:U.S.forestServicefounded *1905:GiffordPinchot *1905:AldoLeopold *1905:AudubonSocietyfounded *1906:AntiquitiesAct *1907-CongressbecameupsetbecauseRooseveltwaswavingsomuch forestlandsotheybannedfurtherwithdrawals. *1912:U.S.NationalParkservicefounded *1933:CivilianConservationCorpsfounded *1930s:DustBowl *1933:SoilConservationServicefounded *1934:TaylorGrazingAct *1934:MigratoryBirdHuntingStampAct *1940:FishplusWildlifeServicefounded *1962:SilentSpringpublishedbyRachelCarson *1963:WildernessAct *1968:WildandScenicRiversAct *1969:CuyahogaRiverinClevelend,Ohio,caughtSire *1969:NEPA(NationalEnvironmentalPolicyAct)

*1970:FirstEarthDay *1970:EnvironmentalProtectionAgencyestablished

*ClearAirAct(*63,*65,*70,*77,*90) *1973:EndangeredSpeciesAct *FIFRA(FederalInsecticide,Fungicide,andRodenticideControl Act,*72,*75,*78,*88) *1973:OPECoilembargo *1974:RolandandMolina(UCI)announcethatCFC’saredepletingthe

ozonelayer *1976:RCRA(ResourceConservationandRecoveryAct) *1977:CleanWaterAct *1977:SurfaceMiningControlandReclamationAct *1978:LoveCanal,NY(toxicwasteleaksintoresidential houses) *1979:3MileIslandNuclearaccident *1980:AlaskanLandsAct *1984:Bhopal,Indian(chemicaltoxiccloudkills2,000) *1986:Chernobyl *CERCLA(ComprehensiveEnvironmentalResponse,Compensation,and LiabilityAct=Super-Fund(*80,*86,*90) *1987:MontrealProtocol *1989:ExxonValdez

*1992:EnergyPolicyActof1992 *1994:DesertProtectionAct *1999:Worldpopulationhits6billion. *1997-2005:KyotoProtocol

Useyourtextbookorsearchesonthewebtogetthedescriptionsofeachitem.Listyour

sources.Canbesubmittedinanyofthefollowingformats:

#1Shouldbehandsubmittedandstapled.

#2DigitallysubmittedthroughHaikudropbox.

#3DigitallysubmittedthroughHaikudropboxunlessapapertimelineisconstructed

Pleasereadandsignbelow:

Asastudentenrolledinthisclass,IafSirmtheprincipleofacademicintegrityandcommitto

upholdingintegritybycompletingallacademicassignmentsmyself.

Iwillnotparticipate,eitherdirectlyorindirectly,incheatingorplagiarism;andIwill

activelydiscouragecheatingorplagiarismbyothersthroughoutthiscourse.

Ihavereadthroughthesummerassignmentandunderstandthedepthandtimecommitmenttocompletethisassignmentoverthesummer.IunderstandImustcompletethesummerassignmentdueonthe?irstdayofAPEnvironmentalclass.Iwillrigorouslyprepareforthe?irstexamgivenonthe?irstdayofclassandknowthatifIdonotscore70%orbetter,ImayberemovedfromAPEnvironmentalScience.

________________________________ _____________________

StudentSignature Date

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Printedname

Compileallworksheetsandplaceinorderinanappropriatebinderorfolder.

Assignmentsshouldbereadybeforeyoucometoclass.Youwillnothavetimetoassemble

andorganizeyourassignmentinclass.15pointpenaltywillbegiventoassignmentsthat

arenotready.Thosewhohavefailedtocompleteentiresummerassignmentwillbe

removedfromthiscourse.

Math Summer Review Environmental Science

Use a separate sheet of paper with your answers. SHOW WORK.

The AP APES exam will involve various calculations and you CANNOT use a calculator during the exam. Therefore for the summer assignment and assessments through the year, you will be required to calculate without a calculator. Most calculations round out in whole numbers or a to a few decimal places. We will focus on how to set up the problems correctly and knowing enough basic to solve the problems. The information in this packet should all be review. This is basic math. If you find the problems challenging, you should consider a different science course.

The Metric System As you recall, the metric system is based on powers of ten.

Tips: *Write out all your work, even if it’s something really simple. This is required on the APES exam. It will be required on all your assignments, labs, quizzes, and tests as well. *Don’t forget to include units in each step. No unit = no credit

Convert the following. 1. 4 grams = _______ milligrams 2. 5 milliliters = __________ cubic centimeters 3. 3.1 kilometers = ______ meters 4. 26 meters = _________ cm 5. 2 kilograms = _______ grams 6. 3425 centimeters = __________ meters

Show your work for the below conversions. 7. 25 miles = _______________Km

8. 10 ounces = ______________ grams

9. 49 ft = ___________________ meters

10. 1.67 yards = _______________mm

Square Meter = The square meter is the basic unit of area of the Metric System. Area is length by width, so, a square that is 1 meter on each side is 1 square meter. The Unit is meters × meters, which is written m2 (square meters). You could have other shapes (such as a rectangle that is ½ a meter by 2 meters) that also make 1 square meter.

The Hectare = A hectare (ha) is an area equal to a square that is 100 meters on each side. So a hectare has 100 m × 100 m = 10,000 m2 (square meters). Hectares are commonly used to measure land.

Square Kilometer = A square kilometer is kilometer × kilometer, which is written km2. A kilometer is a thousand meters, so a square kilometer is also: 1,000 m × 1,000 m = 1,000,000 m2 (square meters). In other words a square kilometer is one-million square meters. Square kilometers are commonly used to measure large areas of land.

Convert the following:

1. 26 m3 = __________hm3 2. 1400 mm3 = __________m3 3. 15 dm3 = __________cm3 4. 32,546 m3 = __________km3

5. 1000 hm3 = __________km3

Converting Temperature:

Convert the following. Show your work: 1. 212ºF = _____________________ºC _____________________________ K 2. 37ºC = _____________________ºF _____________________________ K 3. 42 K = _____________________ºC _____________________________ ºF 4. 70ºF = _____________________ºC _____________________________ K 5. 15º C = ____________________ º F _____________________________ K 6. 212.9K = ____________________ º F _____________________________ ºC

Decimals The basics Decimals are used to show fractional numbers.

Adding or Subtracting Decimals. Remember- no calculators. To add or subtract decimals, make sure you line up the decimals and then fill in any extra spots with zeros. Add or subtract just like usual. Be sure to put a decimal in the answer that is lined up with the ones in the problem.

From To Fahrenheit To Celscius To KelvinFahrenheit (F) F (F-32)/1.8 (F-32)/1.8 + 273.15Celsius (C) (C*1.8) + 32 C C + 273.15Kelvin (K) (K-273.15) *1.8 + 32 K-273.15 K

\ Multiplying Decimals Line up the numbers just as you would if there were no decimals. DO NOT line up the decimals. Write the decimals in the numbers but then ignore them while you are solving the multiplication problem just as you would if there were no decimals at all. After you have your answer, count up all the numbers behind the decimal point(s). Count the same number of places over in your answer and write in the decimal.

Dividing Decimals If the divisor is not a whole number, move decimal point to right to make it a whole number and move decimal point in dividend the same number of places. Divide as usual. Put decimal point directly above decimal point in the dividend.

Dividing Divisors with Decimals Multiply the divisor by a power of 10 to make it a whole number. Multiply the dividend by the same power of 10. Place the decimal point in the quotient. Divide the dividend by the whole-number divisor to find the quotient.

Remember to show all your work, include units if given, and NO CALCULATORS! 1. 1.678 + 2.456 = 2. 344.598 + 276.9 = 3. 1229.078 + .0567 = 4. 45.937 – 13.43 = 5. 199.007 – 124.553 = 6. 90.3 – 32.679 = 7. 28.4 x 9.78 = 8. 324.45 x 98.4 =

9. 1256.93 x 12.38 = 10. 64.5 / 5 = 11. 114.54 / 34.5 = 12. 3300.584 / 34.67 =

Averages To find an average, add all the quantities given and divide the total by the number of quantities.

Example: Find the average of 10, 20, 35, 45, and 105. Step 1: Add all the quantities. 10 + 20 + 35 + 45 + 105 = 215 Step 2: Divide the total by the number of given quantities. 215 / 5 = 43

Practice: Remember to show all your work, include units if given, and NO CALCULATORS!

1. Find the average of the following numbers: 11, 12, 13, 14, 15, 23, and 29 2. Find the average of the following numbers: 124, 456, 788, and 343 3. Find the average of the following numbers: 4.56, .0078, 23.45, and .9872

Percentages Percents show fractions or decimals with a denominator of 100. Always move the decimal TWO places to the right go from a decimal to a percentage or TWO places to the left to go from a percent to a decimal.

Examples: .85 = 85%. .008 = .8%

Finding the Percent of a Given Number To find the percent of a given number, change the percent to a decimal and MULTIPLY.

Example: 30% of 400 Step 1: 30% = .30 Step 2: 400 x .30 12000 Step 3: Count the digits behind the decimal in the problem and add decimal to the answer. 120.00

Finding the Percentage of a Number To find what percentage one number is of another, divide the first number by the second, then convert the decimal answer to a percentage.

Example: What percentage is 12 of 25?

Step 1: 12/25 = .48 Step 2: .48 = 48% (12 is 48% of 25)

Finding a Total Value To find a total value, given a percentage of the value, DIVIDE the given number by the given percentage.

Example: If taxes on a new car are 8% and the taxes add up to $1600, how much is the new car? Step 1: 8% = .08 Step 2: $1600 / .08 = $160,000 / 8 = $20,000

Calculate the following. Show your work. NO CALCULATORS.

1. What is 45% of 900? 2.Thirteen percent of a 12,000 acre forest is being logged. How many acres will be logged? 3.A water heater tank holds 280 gallons. Two percent of the water is lost as steam. How many gallons remain to be used? 4.What percentage is 25 of 162.5? 5. 35 is what percentage of 2800? 6. 4,000 acres of a 40,000 acre forest burned in a forest fire. What percentage of the forest was damaged? 7. You have driven the first 150 miles of a 2000 mile trip. What percentage of the trip have you traveled? 8. Home prices have dropped 5% in the past three years. An average home in Indianapolis three years ago was $130,000. What’s the average home price now? 9. The Greenland Ice Sheet contains 2,850,000 cubic kilometers of ice. It is melting at a rate of .006% per year. How many cubic kilometers are lost each year? 10. 235 acres, or 15%, of a forest is being logged. How large is the forest? 11. A teenager consumes 20% of her calories each day in the form of protein. If she is getting 700 calories a day from protein, how many calories is she consuming per day? 12. In a small oak tree, the biomass of insects makes up 3000 kilograms. This is 4% of the total biomass of the tree. What is the total biomass of the tree?

Scientific Notation Introduction: Scientific notation is a shorthand way to express large or tiny numbers. Since you will need to do calculations throughout the year WITHOUT A CALCULATOR, we will consider anything over 1000 to be a large number. Writing these numbers in scientific notation will help you do your calculations much quicker and easier and will help prevent mistakes in conversions from one unit to another. Like the metric system, scientific notation is based on factors of 10. A large number written in scientific notation looks like this: 1.23 x 1011

The number before the x (1.23) is called the coefficient. The coefficient must be greater than 1 and less than 10. The number after the x is the base number and is always 10. The number in superscript (11) is the exponent.

Writing Numbers in Scientific Notation To write a large number in scientific notation, put a decimal after the first digit. Count the number of digits after the decimal you just wrote in. This will be the exponent. Drop any zeros so that the coefficient contains as few digits as possible. Example: 123,000,000,000 Step 1: Place a decimal after the first digit. 1.23000000000 Step 2: Count the digits after the decimal…there are 11. Step 3: Drop the zeros and write in the exponent. 1.23 x 1011

Writing small numbers in scientific notation is similar. The only difference is the decimal is moved to the left and the exponent is a negative. A tiny number written in scientific notation looks like this:

4.26 x 10-8

To write a tiny number in scientific notation, move the decimal after the first digit that is not a zero. Count the number of digits before the decimal you just wrote in. This will be the exponent as a negative. Drop any zeros before or after the decimal. Example: .0000000426 Step 1: 00000004.26 Step 2: Count the digits before the decimal…there are 8. Step 3: Drop the zeros and write in the exponent as a negative. 4.26 x 10-8

Adding and Subtracting Numbers in Scientific Notation To add or subtract two numbers with exponents, the exponents must be the same. You can do this by moving the decimal one way or another to get the exponents the same. Once the exponents are the same, add (if it’s an addition problem) or subtract (if it’s a subtraction problem) the coefficients just as you would any regular addition problem (review the previous section about decimals if you need to). The exponent will stay the same. Make sure your answer has only one digit before the decimal – you may need to change the exponent of the answer.

Example: 1.35 x 106 + 3.72 x 105 = ? Step 1: Make sure both exponents are the same. It’s usually easier to go with

the larger exponent so you don’t have to change the exponent in your answer, so let’s make both exponents 6 for this problem.

3.72 x 105 .372 x 106

Step 2: Add the coefficients just as you would regular decimals. Remember to line up the decimals.

1.35 + .372

1.722 Step 3: Write your answer including the exponent, which is the same as what

you started with. 1.722 x 106

Multiplying and Dividing Numbers in Scientific Notation To multiply exponents, multiply the coefficients just as you would regular decimals. Then add the exponents to each other. The exponents DO NOT have to be the same.

Example: 1.35 x 106 X 3.72 x 105 = ? Step 1: Multiply the coefficients.

1.35 x 3.72

270 9450 40500

50220 5.022

Step 2: Add the exponents. 5 + 6 = 11 Step 3: Write your final answer. 5.022 x 1011

To divide exponents, divide the coefficients just as you would regular decimals, then subtract the exponents. In some cases, you may end up with a negative exponent.

Example: 5.635 x 103 / 2.45 x 106 = ? Step 1: Divide the coefficients. 5.635 / 3.45 = 2.3 Step 2: Subtract the exponents. 3 – 6 = -3 Step 3: Write your final answer. 2.3 x 10-3

Write the following numbers in scientific notation: 1. 145,000,000,000 2. 13 million 3. 435 billion

4. .000348 5. 135 trillion 6. 24 thousand

Complete the following calculations: 7. 3 x 103 + 4 x 103 8. 4.67 x 104 + 323 x 103 9. 7.89 x 10-6 + 2.35 x 10-8 10. 9.85 x 104 – 6.35 x 104 11. 2.9 x 1011 – 3.7 x 1013 12. 1.278 x 10-13 – 1.021 x 10-10 13. three hundred thousand plus forty-seven thousand 14. 13 million minus 11 thousand 15. 1.32 x 108 X 2.34 x 104 16. 3.78 x 103 X 2.9 x 102 17. three million times eighteen thousand 18. one thousandth of seven thousand 19. eight ten-thousandths of thirty-five million 20. 3.45 x 109 / 2.6 x 103 21. 1.98 x 10-4 / 1.72 x 10-6 22. twelve thousand divided by four thousand

Environmental Science and Technology Briefs for Citizens Page 1Environmental Science and Technology Briefs for Citizens

Understanding Units of Measurement

Technical environmental reports involving soil, water, or air contamination often report numerical values in units unfamiliar to people who don’t routinely read these types of reports. The different units of measurement

Issue 2October 2006

Center for Hazardous Substance Research

Kansas State University • 104 Ward Hall • Manhattan KS 66506 • 785-532-6519 • www.engg.ksu.edu/CHSR/

Terrie K. Boguski, P.E.

Mass28 grams = about 1 ounce1 kilogram (kg) = 1,000 grams1 milligram (mg) = 1/1,000 gram = 0.001 gram1 microgram (ug) = 1/1,000,000 gram = 0.000001 gram1 nanogram (ng) = 1/1,000,000,000 gram = 0.000000001 gram1 picogram (pg) = 1/1,000,000,000,000 gram = 0.000000000001 gram

Concentrations in SoilConcentrations of chemicals in soil are typically mea-sured in units of the mass of chemical (milligrams, mg or micrograms, ug) per mass of soil (kilogram, kg). This is written as mg/kg or ug/kg. Sometimes concentrations in soil are reported as parts per million (ppm) or parts per billion (ppb). Parts per million and parts per billion may be converted from one to the other using this relationship: 1 part per million = 1,000 parts per billion.

For soil, 1 ppm = 1 mg/kg of contaminant in soil, and 1 ppb = 1 ug/kg. A measurement of 6 mg/kg is the same as 6 ppm or 6,000 ppb, which is equal to 6,000 ug/kg.

Concentrations in WaterConcentrations of chemicals in water are typically mea-sured in units of the mass of chemical (milligrams, mg or micrograms, ug) per volume of water (liter, L, l).

can be confusing. This brief is intended to help people understand measurement units they may see in technical environmental reports. Examples of typical units of measurement are given below.

NumbersMillion = 1,000,000Billion = 1,000,000,000Trillion = 1,000,000,000,000One millionth = 0.000001One billionth = 0.000000001One trillionth = 0.000000000001

VolumeOne liter (L) = 1.06 quartsOne cubic meter (m3) = 35.31 cubic feet (ft3)One cubic meter (m3) = 1,000 liters (L)One liter (L) = 1,000 milliliter (ml) = 1,000 cubic centimeters

Concentrations in water can also be expressed as parts per million (ppm) or parts per billion (ppb). Parts per million and parts per billion may be converted from one to the other using this relationship: 1 part per million = 1,000 parts per billion.

For water, 1 ppm = approximately 1 mg/L (also written as mg/l) of contaminant in water, and 1 ppb = 1 ug/L (also written as ug/l). A measurement of 6 mg/L is the same as 6 ppm or 6,000 ppb, which is equal to 6,000 ug/L.

A way to visualize one part per billion (ppb) in water is to think of it as one drop in one billion drops of water or about one drop of water in a swimming pool. One part per million is about 1 cup of water in a swimming pool.

Occasionally, concentrations of chemicals in water may be written as grams per cubic meter (g/m3). This is the same

Environmental Science and Technology Briefs for Citizens Page 2

This publication was edited, designed, and printed by the Center for Hazardous Substance Research (CHSR), Kansas State University, as part of the outreach programs for communities. Programs include Technical Assistance to Brownfi elds communities (TAB) and Techni-cal Outreach Services to Communities (TOSC). Contact the CHSR at 104 Ward Hall, Manhattan, KS 66506; phone: 1-800-798-7796; fax: 785-532-5985; website: http://www.engg.ksu.edu/CHSR/ 02/25/08 SW

ABOUT THE AUTHORTerrie K. Boguski, P.E., is the Assistant Technical Director of the CHSR at Kansas State University (tboguski@ksu.edu).

as grams per 1,000 liters, which may be converted to mil-ligrams per liter (mg/L). Therefore, 1 g/m3 = 1 mg/L = 1 ppm. Likewise, one milligram per cubic meter (mg/m3) is the same concentration in water as one microgram per liter (ug/L), which is about 1 ppb.

Concentrations in AirConcentrations of chemicals in air are typically measured in units of the mass of chemical (milligrams, micrograms, nanograms, or picograms) per volume of air (cubic meter or cubic feet). However, concentrations may also be expressed as parts per million (ppm) or parts per billion (ppb) by using a conversion factor. The conversion factor is based on the molecular weight of the chemical and is different for each chemical. Also, atmospheric tempera-ture and pressure affect the calculation.

Typically, conversions for chemicals in air are made as-suming a pressure of 1 atmosphere and a temperature of 25 degrees Celsius. For these conditions, the equation to convert from concentration in parts per million to con-centration in milligrams per cubic meter (mg/m3) is as follows:

Concentration (mg/m3) = 0.0409 x concentration (ppm) x molecular weight

To convert from mg/m3 to ppm, the equation is as fol-lows:

Concentration (ppm) = 24.45 x concentration (mg/m3) ÷ molecular weight

The same equations may be used to convert micrograms per cubic meter (ug/m3) to parts per billion (ppb) and vice versa:

Concentration (ug/m3) = 0.0409 x concentration (ppb) x molecular weight

Or, concentration (ppb) = 24.45 x concentration (ug/m3) ÷ molecular weight

Here is an example. The molecular weight of benzene is 78. If the concentration of benzene in air is 10 mg/m3, convert to the units of ppm by multiplying 24.45 x 10 mg/m3 ÷ 78 = 3.13 ppm.

Note: Sometimes you will see chemical concentrations in air given in concentration per cubic feet (ft3) instead of concentration per cubic meter (m3). The conversion from cubic feet to cubic meter and vice versa is as follows: 1 ft3

= 0.02832 m3 and 1 m3 = 35.31 ft3.

Name ____________________________________ Period ______

Concentration Calculations Worksheet

Concentration units How the units are calculated molar (M) and millimolar (mM)

Divide moles of solute by volume of solution in liters.

M = moles

L mM = M x 1000

grams per liter (g/L) Divide grams of solute by volume of solution in liters. percent composition Divide mass of solute by total mass of solution, multiply by 100 for percent.

Percent composition is typically used for high concentration solutions.

% composition = g solute

g solution x 100

ppm = parts-per-million Divide mass of solute by total mass of solution, multiply by 1,000,000 (106). Typically used for low concentration solutions such as pollutants in water.

ppm = g solute

g solution x 106 Also equal to mg/L for dilute solutions.

Examples 1. What is the molarity of 10.0 g of salt dissolved in water to make 100. mL?

10.0 g NaCl x 1 mol NaCl58.5 g NaCl = 0.171 mol NaCl

0.171 mol NaCl0.1 L = 1.71 M NaCl

2. How many grams of glucose are in 50.0 mL of a 138 mM solution of glucose in water?

0.050L x 0.138 mol glu

L = 0.00690 mol glu 0.00690 mol glu x 180 g glumol glu = 1.24 g glu

or

0.050L x 0.138 mol glu

L x 180 g glumol glu = 1.24 g glu

3. How many grams of oil are in 500 g of a gasoline-oil mix that is 5% oil?

500 g gasoline-oil x 0.05 g oil

g gasoline-oil = 25 g oil

4. The EPA (Environmental Protection Agency) currently limits the concentration of fluoride in

drinking water to no more than 4.0 mg per liter of water. What is this concentration in parts-per-million (ppm)?

4.0 x 10-3 g F–

L water x 1 L water

103 g water x 106 = 4.0 ppm

2

Problems 1. What is the molarity of the solution when

145 g NaCl is dissolved in water to make 2.75 L of solution?

2. How many grams of potassium chloride are needed to prepare 0.750 L of a 1.50 M solution of KCl in water?

3. What is the molarity of the solution produced when 85.6 g of hydrochloric acid (HCl) is dissolved in enough water to prepare 385 mL of solution?

4. To produce 4.00 L of a 250. mM solution of sodium hydroxide (NaOH), how many grams of NaOH must be dissolved?

5. If 8.77 g of potassium iodide (KI) are dissolved in sufficient water to make 4.75 L of solution, what is the molarity of the solution?

6. What is the concentration in mM of 4.80 g

of citric acid (C6H8O7) dissolved in water to make 1.00 L? (The molar mass of citric acid is 192 g/mole)

7. The concentration of sugar in a soft drink is measured to be 10.5%. How many grams of sugar are in 125 g of the drink?

8. The label on an Ocean Spray Cran-Raspberry drink lists 30 g of sugar in 240 mL of drink. I weighed 240 mL of drink and found its mass to be 251 g. What is the percent composition of sugar in the drink?

9. What is the concentration of sugar in Ocean Spray Cran-Rasberry juice in grams per liter?

10. A drinking water plant adds 500 grams of fluoride to a water tank containing 500,000 liters of drinking water. What is the concentration of fluoride in the water in parts-per-million (ppm)?

3

More Concentration Units

Concentration units How the units are calculated mole fraction (X) Divide moles of component (solute or solvent) by total moles of solution

Xsolute = moles of solute

moles of solution

molal (m) Divide moles of solute by mass of solvent (not solution) in kg

m = moles (solute)kg (solvent)

Examples 5. What are the mole fractions of glucose and water when 50.0 g glucose is dissolved in 100. g H2O?

50.0 g glu x mol glu

180. g glu = 0.278 mol glu 100. g H2O x 1 mole H2O18.0 g H2O = 5.56 mol H2O

0.278 mol glu + 5.56 mol H2O = 5.84 mol total

Xglu = 0.278 mol glu5.84 mol total = 0.0476 Xwater = 1.0000 – 0.0476 = 0.9524

The sum of all the mole fractions is equal to 1. 6. What is the molality of 50.0 g of glucose dissolved in 100. g of water?

50.0 g glu x 1 mol glu180 g glu = 0.278 mol glu

0.278 mol glu0.100 kg water = 2.78 m

Note that 2.78 m is a lower concentration than 2.78 M because addition of 50 g of glucose to 100 mL of water will cause the actual volume of the solution to be greater than 100 mL. Problems 11. A bottle of rubbing alcohol contains 75%

by mass 2-propanol (C3H8O) in water. What are the mole fractions of 2-propanol and water in the solutions?

12. What is the molality of the solution when 328 g NaCl is dissolved in 3.50 kg water?

13. How many grams of ethylene glycol (C2H6O2) are needed to mix with 5.00 kg of water to prepare a 3.50 m solution?

14. 100.0 g of saltwater is weighed out and all of the water evaporated. The remaining salt is found to have a mass of 23.8 g. What was the molality of the original solution? (Hint: Be sure to check the definition of molality before doing this problem!)