chapter 1laboratory chemistry1 chapter 1 chemistry and you

CHAPTER 1 LABORATORY CHEMISTRY 1

CHAPTER 1 CHAPTER 1 CHEMISTRY AND YOUCHEMISTRY AND YOU


WHAT IS CHEMISTRY?WHAT IS CHEMISTRY? CHEMISTRY IN ACTIONCHEMISTRY IN ACTION

– THE CENTRAL SCIENCETHE CENTRAL SCIENCE CHEMISTRY OVERLAPS SO MANY CHEMISTRY OVERLAPS SO MANY

SCIENCESSCIENCES

– WHAT IS CHEMISTRY ?WHAT IS CHEMISTRY ?– WHY STUDY CHEMISTRY?WHY STUDY CHEMISTRY?


WHAT IS CHEMISTRY?WHAT IS CHEMISTRY?

What is chemistry?What is chemistry? How can a knowledge of chemistry help How can a knowledge of chemistry help

a wetlands ecologist or an archeologist a wetlands ecologist or an archeologist do her job?do her job?

Suppose you know a hair stylist who Suppose you know a hair stylist who tells you that in his profession he has no tells you that in his profession he has no need to understand chemistry. What need to understand chemistry. What arguments would you use to convince arguments would you use to convince him that he was mistaken?him that he was mistaken?


THE SCIENTIFIC METHODTHE SCIENTIFIC METHOD A SYSTEMATIC APPROACH A SYSTEMATIC APPROACH

– A WAY OF ANSWERING QUESTIONS AND/OR SOLVING PROBLEMSA WAY OF ANSWERING QUESTIONS AND/OR SOLVING PROBLEMS

STEPS OF THE SCIENTIFIC METHODSTEPS OF THE SCIENTIFIC METHOD– OBSERVATIONOBSERVATION

LEADS TO A QUESTION OR DISCOVERS A PROBLEMLEADS TO A QUESTION OR DISCOVERS A PROBLEM RESEARCH (OBSERVATION, LIBRARY, OTHER)RESEARCH (OBSERVATION, LIBRARY, OTHER)

– HYPOTHESISHYPOTHESIS A TENTATIVE ANSWER TO THE QUESTIONA TENTATIVE ANSWER TO THE QUESTION

– EXPERIMENTEXPERIMENT SCRUPULOUS RECORD KEEPINGSCRUPULOUS RECORD KEEPING ANALYZE DATAANALYZE DATA

– CONCLUSIONCONCLUSION BASED ON THE EXPERIMENTAL DATABASED ON THE EXPERIMENTAL DATA

– REPEAT EXPERIMENTATIONREPEAT EXPERIMENTATION

Hello! I am the Chemistry Mole !

You will see me, or one of my other mole friends, from time-to-time during this

course….when you see us it will mean the material is considered “essential

content” and will be on the Final Exam !

MOLEMOLEMOLEMOLEMOLEMOLE


THE SCIENTIFIC METHODTHE SCIENTIFIC METHODOBSERVATION

QUESTION

HYPOTHESIS

EXPERIMENT

CONCLUSION

NATURAL LAW

THEORY(MODEL)

THEORY MODIFIED

AS NEEDED

PREDICTION

EXPERIMENTREPEAT (EXPERIMENT)


THE SCIENTIFIC METHODTHE SCIENTIFIC METHOD INTERPRETING RESULTSINTERPRETING RESULTS

– EXPERIMENTAL CONTROLSEXPERIMENTAL CONTROLS A CONTROL RESPONDS IN A PREDICTABLE WAY A CONTROL RESPONDS IN A PREDICTABLE WAY

TO THE EXPERIMENT.TO THE EXPERIMENT. LAWS AND THEORIESLAWS AND THEORIES

– NATURAL LAWNATURAL LAW DRAWS TOGETHER MANY OBSERVATIONS AND DRAWS TOGETHER MANY OBSERVATIONS AND

THE RESULTS OF MANY EXPERIMENTS INTO A THE RESULTS OF MANY EXPERIMENTS INTO A “BIG PICTURE”“BIG PICTURE”

DOES NOT EXPLAIN WHAT THE PICTURE MEANSDOES NOT EXPLAIN WHAT THE PICTURE MEANS– THEORYTHEORY

PROVIDES EXPLANATIONPROVIDES EXPLANATION


THE SCIENTIFIC METHODTHE SCIENTIFIC METHOD

What is the scientific method?What is the scientific method? List the steps of the scientific List the steps of the scientific

method.method. What is a variable? An What is a variable? An

experimental control?experimental control? What is the difference between a What is the difference between a

natural law and a scientific theory?natural law and a scientific theory?


UNITS OF MEASUREUNITS OF MEASURE

THE INTERNATIONAL SYSTEM THE INTERNATIONAL SYSTEM OF UNITSOF UNITS ( (SYSTEME SYSTEME INTERNATIONAL D’ UNITESINTERNATIONAL D’ UNITES))– BUILT ON A SET OF SEVEN METRIC BUILT ON A SET OF SEVEN METRIC

UNITS WHICH ARE CALLED THE UNITS WHICH ARE CALLED THE BASE BASE UNITSUNITS OF THE SI OF THE SI



mass kilogram kglength meter mtime second scount, quantity mole moltemperature kelvin Kelectric current ampere Aluminous intensity candela cd

PHYSICAL QUANTITY UNIT NAME SYMBOL

SI BASE UNITSSI BASE UNITS



DERIVED UNITSDERIVED UNITS– IN ADDITION TO THE SEVEN BASE IN ADDITION TO THE SEVEN BASE

UNITS, OTHER SI UNITS CAN BE MADE UNITS, OTHER SI UNITS CAN BE MADE FROM COMBINATIONS OF THE BASE FROM COMBINATIONS OF THE BASE UNITS. USUALLY A CALCULATED UNITS. USUALLY A CALCULATED VALUE…NOT A MEASUREMENT !VALUE…NOT A MEASUREMENT !

AREA (m2) = LENGTH (m) x LENGTH (m) x WIDTH (m)WIDTH (m)



area square meter m2

volume cubic meter m3

force newton Npressure pascal Paenergy joule Jpower watt Wvoltage volt Vfrequency hertz Hzelectric charge coulomb C


DERIVED UNITS USED IN CHEMISTRY



NON SI UNITS USED IN NON SI UNITS USED IN CHEMISTRYCHEMISTRY– IN ADDITION TO THE BASE AND IN ADDITION TO THE BASE AND

DERIVED SI UNITS THERE ARE DERIVED SI UNITS THERE ARE OTHER UNITS COMMONLY USED OTHER UNITS COMMONLY USED IN CHEMISTRYIN CHEMISTRY

THESE ARE NOT SI UNITS, HOWEVER THESE ARE NOT SI UNITS, HOWEVER THEY ARE REGULARLY USED IN THE THEY ARE REGULARLY USED IN THE STUDY OF CHEMISTRYSTUDY OF CHEMISTRY



volume liter Lpressure atmosphere atm

millimeters of mercury mmHgtemperature Celsius degree Co

energy calories cal


NON-SI UNITS USED IN CHEMISTRY



METRIC PREFIXESMETRIC PREFIXES– A METRIC PREFIX IS ATTACHED TO A METRIC PREFIX IS ATTACHED TO

THE BASE UNIT, CREATING A MORE THE BASE UNIT, CREATING A MORE CONVENIENT, EASIER TO USE UNIT.CONVENIENT, EASIER TO USE UNIT.

– PREFIXES CAN MAKE THE NEW UNIT PREFIXES CAN MAKE THE NEW UNIT LARGER OR SMALLER THAN THE BASE LARGER OR SMALLER THAN THE BASE UNITUNIT


UNITS OF MEASUREUNITS OF MEASURECOMMON PREFIXESCOMMON PREFIXES

Giga- G 1 000 000 000 109

mega- M 1 000 000 106

kilo- k 1 000 103

hecto- h 100 102

deka- D (Dk) 10 101

ROOT UNIT meter, liter, gram 1 100

deci- d 0.1 10-1

centi- c 0.01 10-2

milli- m 0.001 10-3

micro- 0.000 001 10-6

nano- n 0.000 000 001 10-9

pico- p 0.000 000 000 001 10-12

PREFIX ABBREVIATION VALUE SCI. NOTATION



What are the SI units for length, What are the SI units for length, mass, and volume?mass, and volume?

What is a metric prefix? What What is a metric prefix? What does the metric prefix centi- does the metric prefix centi- mean? The prefix deci- ?mean? The prefix deci- ?

What is the difference between What is the difference between mass and weight?mass and weight?


UNCERTAINTY IN MEASUREMENTUNCERTAINTY IN MEASUREMENT

MAKING MEASUREMENTSMAKING MEASUREMENTS– IN MAKING A MEASUREMENT, YOU WRITE IN MAKING A MEASUREMENT, YOU WRITE

DOWN DOWN ALL OF THE CERTAIN (OR EXACT) ALL OF THE CERTAIN (OR EXACT) DIGITSDIGITS THAT THE INSTRUMENT CAN GIVE AND THAT THE INSTRUMENT CAN GIVE AND ALSO ALSO ONE UNCERTAIN DIGITONE UNCERTAIN DIGIT YOU ESTIMATE. YOU ESTIMATE.

– MEASUREMENTS ARE UNCERTAIN FOR TWO MEASUREMENTS ARE UNCERTAIN FOR TWO REASONS:REASONS:

1.1. MEASURING INSTRUMENTS ARE MEASURING INSTRUMENTS ARE NEVER NEVER COMPLETELY FREE OF FLAWS.COMPLETELY FREE OF FLAWS.

2.2. MEASURING ALWAYS INVOLVES SOME MEASURING ALWAYS INVOLVES SOME ESTIMATION.ESTIMATION.



ESTIMATING WITH A DIGITAL ESTIMATING WITH A DIGITAL DISPLAYDISPLAY– Instruments with a digital displayInstruments with a digital display

The final digit is the estimated digitThe final digit is the estimated digit The estimated digit is done for you The estimated digit is done for you

electronicallyelectronically– it can sometimes “flicker”, if this happens it can sometimes “flicker”, if this happens

you should record the reading that you should record the reading that instrument “prefers”.instrument “prefers”.

– REMEMBER TO LABEL YOUR REMEMBER TO LABEL YOUR MEASUREMENT (GRAM, KILOGRAM, MEASUREMENT (GRAM, KILOGRAM, ooC, C, etc.)etc.)



ESTIMATING WITH A SCALEESTIMATING WITH A SCALE

30

25

20

15

10

5

30

25

20

15

10

5

MINISCUS23 1



RELIABILITY IN MEASUREMENTRELIABILITY IN MEASUREMENT– THERE ARE TWO WAYS TO CHECK THERE ARE TWO WAYS TO CHECK

RELIABILITYRELIABILITY PRECISION:PRECISION: REPEAT THE REPEAT THE

MEASUREMENT SEVERAL TIMES….A MEASUREMENT SEVERAL TIMES….A RELIABLE MEASUREMENT WILL GIVE ABOUT RELIABLE MEASUREMENT WILL GIVE ABOUT THE SAME RESULT AGAIN AND AGAIN.THE SAME RESULT AGAIN AND AGAIN.

ACCURACY:ACCURACY: THE SECOND WAY IS TO THE SECOND WAY IS TO CHECK THE RESULTS AGAINST A STANDARD. CHECK THE RESULTS AGAINST A STANDARD. A MEASUREMENT THAT IS ACCURATE IS ONE A MEASUREMENT THAT IS ACCURATE IS ONE THAT IS CLOSE TO THE ACCEPTED THAT IS CLOSE TO THE ACCEPTED STANDARD.STANDARD.


UNCERTAINTY IN MEASUREMENTUNCERTAINTY IN MEASUREMENTPRECISE

BUTNOT ACCURATE

BOTHPRECISE

AND ACCURATE

NOT PRECISE

NOR ACCURATE



Explain why measurements are Explain why measurements are always uncertain.always uncertain.

Describe two ways to check the Describe two ways to check the reliability of a measurement.reliability of a measurement.

How would you find the uncertain How would you find the uncertain digit in a measurement using a digit in a measurement using a digital display? Using a scale ?digital display? Using a scale ?


WORKING WITH NUMBERSWORKING WITH NUMBERS

SIGNIFICANT DIGITSSIGNIFICANT DIGITS– WHEN MEASUREMENTS ARE COMBINED WHEN MEASUREMENTS ARE COMBINED

MATHEMATICALLY, THE UNCERTAINTY OF MATHEMATICALLY, THE UNCERTAINTY OF THE SEPARATE MEASUREMENTS MUST BE THE SEPARATE MEASUREMENTS MUST BE CORRECTLY REFLECTED IN THE FINAL CORRECTLY REFLECTED IN THE FINAL RESULT.RESULT.

– THE CERTAIN DIGITS AND THE ESTIMATED THE CERTAIN DIGITS AND THE ESTIMATED DIGIT OF A MEASUREMENT ARE TOGETHER DIGIT OF A MEASUREMENT ARE TOGETHER CALLED THE SIGNIFICANT DIGITS OF THE CALLED THE SIGNIFICANT DIGITS OF THE MEASUREMENT.MEASUREMENT.



WHEN A ZERO IS NOT WHEN A ZERO IS NOT SIGNIFICANTSIGNIFICANT– A ZERO THAT IS SIMPLY A PLACE-A ZERO THAT IS SIMPLY A PLACE-

KEEPER IN A MEASUREMENT IS NOT KEEPER IN A MEASUREMENT IS NOT SIGNIFICANT.SIGNIFICANT.

– TO DETERMINE IF A ZERO IS TO DETERMINE IF A ZERO IS SIGNIFICANT OR NOT SIGNIFICANT SIGNIFICANT OR NOT SIGNIFICANT FOLLOW THIS SIMPLE METHOD.FOLLOW THIS SIMPLE METHOD.


WORKING WITH NUMBERSWORKING WITH NUMBERS0.00120010

READ FROM THE LEFT AND BEGIN COUNTING SIGNIFICANT DIGITS AT THE

FIRST NUMBER OTHER THAN ZERO

IF THERE IS A DECIMAL IN THE NUMBER…. ZEROS AT THE END OF THE

NUMBER CHAIN COUNT ! IF THERE IS NO DECIMAL IN THE

NUMBER THE FINAL ZERO(S) DO NOTCOUNT !

0.001200100.001200100.001200100.001200100.001200100.001200100.001200100.001200100.00120010



SIGNIFICANT DIGITS IN CALCULATIONSSIGNIFICANT DIGITS IN CALCULATIONS– WHEN AN EXACT NUMBER APPEARS IN WHEN AN EXACT NUMBER APPEARS IN

A CALCULATION, IT DOES NOT AFFECT A CALCULATION, IT DOES NOT AFFECT THE NUMBER OF SIGNIFICANT DIGITS THE NUMBER OF SIGNIFICANT DIGITS IN THE FINAL ANSWER. IN THE FINAL ANSWER.

EXACT NUMBERS ARE NOT MEASUREMENTS, EXACT NUMBERS ARE NOT MEASUREMENTS, BUT ARISE FROM A DEFINITION (I.E. 100O BUT ARISE FROM A DEFINITION (I.E. 100O METERS = 1 KILOMETER) THIS IS A METERS = 1 KILOMETER) THIS IS A DEFINITION, NOT A MEASUREMENT!DEFINITION, NOT A MEASUREMENT!

– A DEFINITION HAS AN INFINITE NUMBER OF A DEFINITION HAS AN INFINITE NUMBER OF SIGNIFICANT DIGITSSIGNIFICANT DIGITS



– IN MULTIPLICATION AND DIVISIONIN MULTIPLICATION AND DIVISION THE MEASUREMENT WITH THE SMALLEST THE MEASUREMENT WITH THE SMALLEST

NUMBER OF SIGNIFICANT DIGITS NUMBER OF SIGNIFICANT DIGITS DETERMINES HOW MANY DIGITS ARE DETERMINES HOW MANY DIGITS ARE ALLOWED IN THE FINAL ANSWER.ALLOWED IN THE FINAL ANSWER.

– IN ADDITION AND SUBTRACTIONIN ADDITION AND SUBTRACTION THE NUMBER OF SIGNIFICANT DIGITS THE NUMBER OF SIGNIFICANT DIGITS

ALLOWED DEPENDS ON THE NUMBER ALLOWED DEPENDS ON THE NUMBER WITH THE LARGEST UNCERTAINTY.WITH THE LARGEST UNCERTAINTY.



100400

1.00400

0.100400

0.00400

10040.

4 SIGNIFICANT DIGITS







61.00500.0050

3.3420

484.0100

480

231.22

X 5.0

1156.1

1200


WORKING WITH NUMBERSWORKING WITH NUMBERS SCIENTIFIC NOTATIONSCIENTIFIC NOTATION

– CONVERTING NUMBERS TO SCIENTIFIC CONVERTING NUMBERS TO SCIENTIFIC NOTATIONNOTATION

TO WRITE NUMBERS IN SCIENTIFIC NOTATION, TO WRITE NUMBERS IN SCIENTIFIC NOTATION, THE PROPER EXPONENT CAN BE FOUND BY THE PROPER EXPONENT CAN BE FOUND BY COUNTING HOW MANY TIMES THE DECIMAL COUNTING HOW MANY TIMES THE DECIMAL POINT MUST BE MOVED TO BRING IT TO ITS POINT MUST BE MOVED TO BRING IT TO ITS FINAL POSITION SO THAT THE NUMBER IS FINAL POSITION SO THAT THE NUMBER IS BETWEEN 1 AND 10.BETWEEN 1 AND 10.

IF THE NUMBER IS LESS THAN 1 THE EXPONENT IF THE NUMBER IS LESS THAN 1 THE EXPONENT OF 10 IS NEGATIVE 10OF 10 IS NEGATIVE 10-X-X

IF THE NUMBER IS GREATER THAN 1 THE IF THE NUMBER IS GREATER THAN 1 THE EXPONENT IS POSITIVE 10EXPONENT IS POSITIVE 10XX



32,700 3.27 X 104

O.OOO341

45,500,000

0.0000234

3.41 X 10-4

4.55 X 107

2.34 X 10-5



32,500

5.6 X 10-6

0.002260

5.939

7.25 X 103

0.00000560.0000056

7,2507,250

3.25 X 103.25 X 1044

2.260 X 102.260 X 10-3-3

5.939 X 105.939 X 1000



PERCENTS AND PERCENT PERCENTS AND PERCENT ERRORERROR

RATIOSRATIOS

MEASURED VALUE - ACCEPTED VALUE

ACCEPTED VALUEX 100

THEORETICALEXPERIMENTAL

THEORETICAL

ACCEPTED VALUE ACCEPTED AMOUNT

GIVEN VALUE GIVEN AMOUNT

IF

THEN==



What are significant digits?What are significant digits? Describe how the Atlantic-Pacific Describe how the Atlantic-Pacific

rule can be used to help find the rule can be used to help find the significant digits in a significant digits in a measurement.measurement.

How can you calculate the density How can you calculate the density of an object?of an object?


PROBLEM SOLVINGPROBLEM SOLVING

FOUR STEP PROBLEM SOLVING FOUR STEP PROBLEM SOLVING STRATEGYSTRATEGY– ANALYZE:ANALYZE:

READ THE ENTIRE PROBLEM CAREFULLY. READ THE ENTIRE PROBLEM CAREFULLY. IDENTIFY THE UNKNOWN QUANTITY IN THE IDENTIFY THE UNKNOWN QUANTITY IN THE

PROBLEM AND CHOSE A SYMBOL TO PROBLEM AND CHOSE A SYMBOL TO REPRESENT ITREPRESENT IT

ORGANIZE THE GIVEN INFORMATION (USE A ORGANIZE THE GIVEN INFORMATION (USE A TABLE OR LIST)TABLE OR LIST)

SKETCH A PICTURE OR DIAGRAM TO HELP SKETCH A PICTURE OR DIAGRAM TO HELP CLARIFY THE PROBLEMCLARIFY THE PROBLEM


PROBLEM SOLVINGPROBLEM SOLVING– PLAN:PLAN:

IS THE PROBLEM SIMILAR TO ANY YOU HAVE IS THE PROBLEM SIMILAR TO ANY YOU HAVE SEEN BEFORE?SEEN BEFORE?

REVIEW EARLIER PROBLEMS FOR CLUES TO REVIEW EARLIER PROBLEMS FOR CLUES TO CONNECTING THE UNKNOWN TO THE GIVEN CONNECTING THE UNKNOWN TO THE GIVEN INFORMATIONINFORMATION

WRITE DOWN ANY EQUATIONS THAT LINK THE WRITE DOWN ANY EQUATIONS THAT LINK THE UNKNOWN AND THE GIVENINFORMATION UNKNOWN AND THE GIVENINFORMATION TOGETHERTOGETHER

MAKE A PLAN FOR SOLVING THE PROBLEMMAKE A PLAN FOR SOLVING THE PROBLEM MAKE AN ESTIMATE OF THE ANSWER (“WHAT MAKE AN ESTIMATE OF THE ANSWER (“WHAT

WOULD BE A REASONABLE ANSWER IN THIS WOULD BE A REASONABLE ANSWER IN THIS CASE?”)CASE?”)



– SOLVE:SOLVE: PERFORM THE MATHEMATICAL STEPS PERFORM THE MATHEMATICAL STEPS

OUTLINED IN YOUR PLAN.OUTLINED IN YOUR PLAN. CHECK UNITS AND SIGNIFICANT DIGITSCHECK UNITS AND SIGNIFICANT DIGITS

– EVALUATE:EVALUATE: ASK YOURSELF, DOES THIS ANSWER THE ASK YOURSELF, DOES THIS ANSWER THE

QUESTION ?QUESTION ? DOES THE ANSWER MAKE SENSE?DOES THE ANSWER MAKE SENSE? COMPARE THE ANSWER (NUMERICAL VALUE COMPARE THE ANSWER (NUMERICAL VALUE

AND UNITS) WITH YOUR ESTIMATE.AND UNITS) WITH YOUR ESTIMATE.



CONVERSIONS

CONVERTING WITHIN THE SI SYSTEM

CONVERSIONS IN THE SAME DIMENSIONUSING LINEAR, SQUARE, AND CUBIC MEASUREMENTS

CONVERSIONS IN DIFFERENT DIMENSIONSCHANGING CUBIC, MASS AND VOLUME MEASUREMENTS

USING WATER


PROBLEM SOLVING: ConversionsPROBLEM SOLVING: Conversions

Convert 234 mL into L.

Step 1 KiloHectoDekaStandard (m, L,g)decicentimilli You are at milli-

You want to go to Liters

1

2

3That’s three steps



Step 2 Write the number in scientific notation

2342.34

Write the number by placing the decimalBehind the first number (other than zero)

Write the exponential notation (x 10 )

X 10

Count the number of places you need to move the decimal to get back to the

original number…in this case “2”..use that number as the exponent of 10

2



Step 3 Final Conversion

Write the “Conversion Factor” (1.0 x 10 )

2.34 x 102

1.0 x 10

Make the exponent of 10 the number of steps you counted in Step 1

If you went UP the scale make it negative (-)If you went DOWN the scale make it positive (+)

2.34 x 10-1 Now simply multiply the two numbers (remember your math rules [add exponents])

And that’s the answer!

1.0 x 10-3

?

x



SUMMARY

234 mL = 2.34 x 10-1 L

2.34 x 102

2.34 x 10-1

1.0 x 10-3x



DIMENSIONAL ANALYSISDIMENSIONAL ANALYSIS– THE TECHNIQUE OF CONVERTING BETWEEN THE TECHNIQUE OF CONVERTING BETWEEN

UNITSUNITS– UNIT EQUALITIES: AN EQUATION THAT UNIT EQUALITIES: AN EQUATION THAT

SHOWS HOW DIFFERENT UNITS ARE SHOWS HOW DIFFERENT UNITS ARE RELATEDRELATED

METRIC TO METRICMETRIC TO METRIC ENGLISH TO METRICENGLISH TO METRIC

– CONVERSION FACTORS: AN EQUATION THAT CONVERSION FACTORS: AN EQUATION THAT IS ALWAYS EQUAL TO ONE (1).IS ALWAYS EQUAL TO ONE (1).


PROBLEM SOLVING: Dimensional PROBLEM SOLVING: Dimensional AnalysisAnalysis

Dimensional Analysis is an extension of the Conversion method we just used. The most important

Concept here is to “ORGANIZE” the problem.Don’t let the number of steps frighten you!

157 m3 = ___________ Kg

In all of these problems we are dealing with water (H2O) at standard conditions (Standard Temperature and Pressure) (STP).

Which is 0 oC and 1 atm . Since water has a density of 1 g/cm3 at Standard Conditions….We can equate:

1 g = 1 mL = 1cm3



Organizaton

First: Write the problem!

Second: Set the proper equality under the problem

Third: Plan your problem..Use arrows to determine the

Direction of movement.

157 L = ___________ Kg

mL = _____________ g


Remember that mL and Grams Equate (1 mL = 1 g)


157 L = ___________ Kg

mL = _____________ g

1 2

Basically, what you have done was to arrange the problem into

two(2) simple conversions!

157 L = _____________ mL

g = _____________ Kg

1

2



157 L = ____________ Kg

mL = ____________ g

1 2

157 L = _________ mL

g = __________ Kg

1

2

1.57 x 102

1.00 x 103

1.57 x 105x

1.57 x 105

1.00 x 10-3

1.57 x 102x

g = 1.57 x 102 Kg

157 L = 1.57 x 105 mL

mL = 1.57 x 105 g

157 L = 1.57 x 102 Kg


PROBLEM SOLVINGPROBLEM SOLVING GRAPHINGGRAPHING

– SCIENTIFIC GRAPHS SHOW THE RELATIONSHIP SCIENTIFIC GRAPHS SHOW THE RELATIONSHIP BETWEEN TWO EXPERIMENTAL VARIABLESBETWEEN TWO EXPERIMENTAL VARIABLES

ONE VARIABLE IS CALLED THE ONE VARIABLE IS CALLED THE INDEPENDENT INDEPENDENT VARIABLEVARIABLE (THE ONE THAT CHANGES IN THE (THE ONE THAT CHANGES IN THE EXPERIMENT)EXPERIMENT)

– PLOTTED ON THE HORIZONTAL (X) AXIS OF THE PLOTTED ON THE HORIZONTAL (X) AXIS OF THE GRAPHGRAPH

THE SECOND VARIABLE, CALLED THE THE SECOND VARIABLE, CALLED THE DEPENDENT VARIABLEDEPENDENT VARIABLE (RESPONDS TO CHANGES (RESPONDS TO CHANGES IN THE INDEPENDENT VARIABLE)]IN THE INDEPENDENT VARIABLE)]

– PLOTTED ON THE VERTICAL (Y) AXIS OF THE PLOTTED ON THE VERTICAL (Y) AXIS OF THE GRAPHGRAPH


TEMP

OC

TIME (MIN)

5

10

15

20

00 1 2 3 4 5

DEPENDENTVARIABLE

INDEPENDENTVARIABLE

FIGURE 1-A TEMP VS TIME EXPERIMENT



– LABEL EACH AXIS OF A GRAPH WITH LABEL EACH AXIS OF A GRAPH WITH THE NAME OF THE VARIABLE AND THE THE NAME OF THE VARIABLE AND THE UNITS OF MEASUREUNITS OF MEASURE

– CONVERT EACH PAIR OF CONVERT EACH PAIR OF MEASUREMENTS INTO A POINT ON THE MEASUREMENTS INTO A POINT ON THE GRAPHGRAPH

– CONNECT THE DATA POINTS WITH A CONNECT THE DATA POINTS WITH A “BEST FIT” LINE“BEST FIT” LINE

– TITLE THE GRAPH WHEN IT IS COMPLETETITLE THE GRAPH WHEN IT IS COMPLETE


TEMP

OC

TIME (MIN)

5

10

15

20

00 1 2 3 4 5

DEPENDENTVARIABLE

INDEPENDENTVARIABLE

FIGURE 1-A TEMP VS TIME EXPERIMENT


PROBLEM SOLVINGPROBLEM SOLVINGCOMMON FORMULAS USED IN CHEMISTRY

DENSITY=MASS

VOLUME

VOLUME =LENGTH X WIDTH X HEIGHT

CYLINDER VOLUME = r2 h

PRESSURE =FORCE

AREA 1g = 1mL = 1cm3

oF = 1.8 oC + 32oC = 0.555 (oF-32)

K = oC +273

PERCENT ERROR =MEASURED VALUE – ACCEPTED VALUE

ACCEPTED VALUE

X 100



What is meant by dimensional What is meant by dimensional analysis?analysis?

What is a unit equality? A What is a unit equality? A conversion factor?conversion factor?

List and describe the four steps List and describe the four steps that can be used to solve problems that can be used to solve problems in chemistry.in chemistry.

chapter 1laboratory chemistry1 chapter 1 chemistry and you

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