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Measurement and Calculations. Mr. Glavan Riverside Local school District Chemistry 1 Fall 2014. Chapters 1 & 2: Measurement and Calculations. Learning Targets Identify a given substance as an element or compound Classify properties and changes as chemical or physical

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measurement and calculations

Measurement and Calculations

Mr. Glavan

Riverside Local school District

Chemistry 1

Fall 2014

chapters 1 2 measurement and calculations

Chapters 1 & 2:Measurement and Calculations

Learning Targets

Identify a given substance as an element or compound

Classify properties and changes as chemical or physical

Explain the structure of the periodic including properties of elements based on their location (metal, nonmetal, etc.)

Determine the amount of heat transferred in a process

Express data and results of calculations with appropriate significant figures, units, and in scientific notation

Calculate percent error from lab data and use this to evaluate the quality of lab data

Perform density calculations and apply density conceptually (e.g. identifying substances or determining if an object will float

key words
Key Words
  • atom
  • compound
  • element
  • pure substance
  • mixture
  • homogeneous/heterogeneous
  • chemical change/property
  • physical change/property
  • direct/inverse proportion
  • family/group
  • period
  • significant figure
  • scientific notation
  • conversion factor
  • percent error
  • metal
  • nonmetal
  • metalloid
  • noble gas
  • quantitative
  • qualitative
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 23
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23
  • Matter is anything that has volume and mass
  • Mass is a measure of the amount of matter present
  • Volume is the amount of space an object occupies
  • Atoms are the fundamental building block of matter
  • Elements are pure substances made of one type of atom
  • Compounds are substances made from the atoms of two or more elements
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 231
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23

Properties of Matter

  • Matter has physical properties and can undergo physical changes
  • Physical properties are observed without changing the identity of a substance (examples include: density, color, melting point)
  • Physical changes don’t involve a change in a substance’s identity (examples include: phase change, breaking)
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 232
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23

Properties of Matter

  • Matter has chemical properties and can undergo chemical changes
  • Chemical properties relate to a substance’s ability to become a new substance (example: flammability, corrosiveness)
  • Chemical changes involve a change in a substance’s identity
  • Chemical Equation (Reactants to Products)
section 1 classifying and changing matter
Section 1: Classifying and Changing Matter

Signs of a Chemical Change

  • Gas Production
  • Formation of a Precipitate
  • Dramatic Temperature Change
  • Unexpected Color Change
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 233
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23

Classification of Matter

  • Matter can be classified as either a pure substance or a mixture
  • Pure Substances are fixed ratios and can be either a element or a compound.
  • Elements are found on the periodic table, They can not be broken down by physical means.
  • Compounds are substances made of two or more elements.
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 234
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23

Classification of Matter

  • Mixtures are blends of two or more types of matter, each retaining its own identity and properties
  • Mixtures are combined physically and can be separated using physical means
  • There are two types of mixtures:
    • Homogenous –they are unified throughout
    • Heterogenous – not evenly mixed
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 235
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 236
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23

Periodic Table

  • The periodic table organizes elements into groups based on similar properties
  • The vertical columns are known as groups or families; elements in the same group have similar chemical properties
  • The horizontal rows are called periods; elements in the same period don’t necessarily have similar chemical properties
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 237
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23
section 1 classifying and changing matter pages 26 27 rbqs pgs 59 61 9 11 14 15 18 21 238
Section 1: Classifying and Changing MatterPages 26-27 RBQs Pgs. 59-61 #9-11,14, 15, 18-21,23
  • Metals:
  • Nonmetals:
  • Metalloids:
  • Noble Gases:
which of the following is a chemical change
Which of the following is a chemical change?
  • Sanding wood
  • Melting ice
  • Milk going sour
  • Vaporizing of gasoline
blood would be considered
Blood would be considered
  • Element
  • Compound
  • Homogenous mixture
  • Heterogenous mixture
section 2 scientific notation sig figs pages 46 52 rbqs pgs 5 9 61 21 23 36 46

Section 2 : Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46

Scientific notation is a ay of taking very large numbers and/or very small numbers and writing them more simply

For example, an important number in chemistry is

602,000,000,000,000,000,000,000which suck to write…but in scientific notation it is6.02 x 1023

section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 46

Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46

Exercise: Use the examples below to come up with a set of rules for converting from scientific to regular notation.Sci. NotationReg. NotationSci. NotationReg. Notation 4.521 x 105 452,100 8.2 x 10-8 .0000000823.8862 x 102 388.62 6.447 x 10-4 .0006447

section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 461

Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46

Exercise: Use the examples below to come up with a set of rules for converting from regular to scientific notation.Sci. NotationReg. NotationSci. NotationReg. Notation 817 8.18 x 102 0.00456 4.56 x 10-3 0.000006 6 x 10-6 48260000 4.826 x 107

convert 506100 to scientific notation
Convert 506100 to scientific notation:
  • 5 x 105
  • 5.1 x 10 -5
  • 5.061 x 105
  • 51 x 105
which of the following is not in scientific notation
Which of the following is not in scientific notation?
  • 2.31 x 108
  • 2.31 x 10-3
  • 231 x 107
  • 2.31 x 1056
  • 2.31 x 103
section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 462
Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46
  • Measurements made in the lab are never perfect
  • Data can only include numbers that we are sureof
  • Record all numbers you aresure of, then estimate anadditional number
section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 463
Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46
  • Numbers given this way are called significant figures
  • Sig figs also indicate how accurate a measuring device is
section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 464
Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46
  • Since numbers are often given in a question and not gathered in a lab, it is important to be able to look at a number and determine how many significant figures it contains
  • Also, the number of significant figures in an answer will depend on the sig figs contained in the numbers in the question
  • Applying sig fig rules to math ensures that no uncertain numbers will be in your answers
section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 465
Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46

When are nonzero numbers significant? (circle one) Always Sometimes Never

When are leading zeros significant? (circle one) Always Sometimes Never

When are captive zeros significant? (circle one) Always Sometimes Never

When are trailing zeros significant? (circle one) Always Sometimes Never

round 2 00152 to four significant figures
Round 2.00152 to four significant figures
  • 2.002
  • 2.001
  • 2.000
  • 2.152
  • None of these
section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 466
Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46
  • Significant figure rules also exist and must be applied when performing calculations
  • There is one rule for addition and subtraction and a second rule for multiplication and division
  • The exercises on the following slides will illustrate these rules
section 1 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 46
Section 1: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46

X

&

÷

2.0 x 4 = 89.166 x 3.2 = 292.66543 x 0.0032 = .00850.02 ÷ 0.00606894 = 3

2.44 x 8.629 = 21.1199.2 ÷ 4.05 = 49.20.026 x 0.00449 = .00012(5.4 x 102)(6.39 x 10-6) = 3.5 x 10-3

Determine the number of significant figures in each answer above.

Determine the number of significant figures in each number in the questions above.

How is the number of significant figures in the answer determined? (write in space below)

section 2 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 467
Section 2: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46

+

&

-

8.663 – 2.1 = 6.61.00036 + 0.2 = 1.28.365434534385 + 1 = 968.633 + 7.9343 = 76.567

14.2 + 2 = 169.887467 – 2.003 = 7.8846.22 + 2.1 = 8.34.0 + 12.98373 = 17.0

Determine the number of decimal places in each answer above.

Determine the number of decimal places in each number in the questions above.

How is the number of decimal places in the answer determined? (write in space below)

sample what is the product of 4 56 and 1 4 reported with correct significant figures
Sample: What is the product of 4.56 and 1.4, reported with correct significant figures?
  • 6.384
  • 6.38
  • 6.3
  • 6.4
  • 6
sample what is 4 56 1 4 reported with correct significant figures
Sample: What is 4.56 - 1.4, reported with correct significant figures?
  • 3.16
  • 3.2
  • 3.1
  • 3.160
  • 3
sample do this and with correct sig figs 4 184 x 100 62 x 25 27 24 16
Sample: Do this! And with correct sig figs! 4.184 x 100.62 x (25.27 – 24.16) = ?
  • 470
  • 467.3
  • 467.30
  • 460
  • 467
sample do this and with correct sig figs 6 0 x 10 23 4 22
Sample: Do this! And with correct sig figs! (6.0 x 1023)(4.22) = ?
  • 2.532 x 1024
  • 2.5 x 1024
  • 2.53 x 1024
  • 3 x 1024
  • 2.5320 x 1024
section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 49

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

A key skill in chemistry is being able to convert from one unit of measurement to another

For example, converting from one unit of distance to another such as feet to miles

Using conversion factors is done using the same approach taken to multiplying fractions

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 491

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Determine the answers to following problems:

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 492

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

In each case, notice how a common numerator and denominator cancelled each other

This same idea is the key idea to using conversion factors

With conversion factors, the difference is that you select the fraction to the answer you want

section 2 conversion factors pages 40 42 rbqs pgs 60 61 28 32 49

Section 2: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

To convert one unit to another, e.g. pounds to grams, the same principles as above are used

Arrange units as needed to get the desired unit

The fraction used to convert one unit to another is known as a conversion factor

pounds x ---------------- = grams

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 493

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Set up the appropriate conversion factor for the following:

Inches to centimeters

Miles per hour to meters per minute

sample what is the correct conversion factor for converting feet to inches
Sample: What is the correct conversion factor for converting feet to inches?

A. Feet

Inches

  • Inches

Feet

sample what is the correct conversion factor to convert feet per second to inches per minute
Sample: What is the correct conversion factor to convert feet per second to inches per minute?
  • Feet x seconds

inches minutes

B. Inches x minutes

feet seconds

C. Feet x minutes

inches seconds

D. Inches x seconds

minutes feet

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 494

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

The numerical relationship between units must be taken into account as well

For example, to convert feet to inches, you need to know that there are 12 inches in one foot

Once the units are in place, the final step is to put each number with its unit

Potentially Useful Information

1 ft3 = 28.32 L 1 mi = 1.609 km 1 in3 = 16.38 cm3 1 in = 2.54 cm

1 kg = 2.2 lbs 1 oz = 28.35 g 1 lb = 16 oz 1 gallon = 3.785 L

1 lb = 453.59 g 1 ft = 12 in 1 ft3 = 1728 in3 3 ft = 1 yd

1 m = 3.281 ft 1 mi = 5280 ft 1 cal = 4.184 J

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 495

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Determine the answers to following problems:

a) How many inches are there in 2.0 feet?

b)How many seconds are in 3 hours?

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 496
Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49
  • Convert miles per hour to meters per minute
sample what speed in meters per minutes is equivalent to 20 0 feet per second
Sample: What speed, in meters per minutes, is equivalent to 20.0 feet per second?
  • 3930 m/min
  • .101 m/min
  • 1.09 m/min
  • 366 m/min
section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 497

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Pay special attention to any unit containing the word “per”; for example:miles per hour – mi/hr meters per second – m/s

grams per mole – g/mol grams per liter – g/L

These units are always determined by dividing the two units

grams per mole = grams ÷ moles

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 498

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

When a measurement has a unit with the word “per” in it, it is a conversion factor

For example, speed in mi/hr is the number of miles driven in 1 hour

25 miles per hour means 25 miles in I hour, so….25 miles = 1 hour

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 499

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Determine the answers to following problem:

a) If your drive for four hours at a speed of 25 miles per hour, how many miles will you drive?

sample a metal has a density of 17 4 g ml how many ml of space will 11 1 g of this metal occupy
Sample: A metal has a density of 17.4 g/mL. How many mL of space will 11. 1 g of this metal occupy?
  • 17.4 mL
  • 11.1 mL
  • .638 mL
  • 1.57 mL
slide57

Sample: The molar mass of a substance is measured in the unit of grams per mole. If a sample of a substance is found to contain 3.55 moles and a mass of 79.2 grams, what is its molar mass?

  • .0448 g/mol
  • 22.3 g/mol
  • 3.55 g/mol
  • 281 g/mol
section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 4910

Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Metric conversions (mL to L, g to kg) can be performed without the use of conversion factors

To convert these unit, just move the decimal the appropriate number of places

This works because the metric prefixes always change the value of a number by a factor of 10, which is what you do when you move a decimal point

section 3 conversion factors pages 40 42 rbqs pgs 60 61 28 32 4911
Section 3: Conversion FactorsPages 40-42 RBQs Pgs. 60-61 #28-32, 49

Kangaroos Have Dandruff But Don’t Care Much

sample how many kilometers are there in 8 230 mm
Sample: How many kilometers are there in 8,230 mm?
  • 82,300 km
  • .00823 km
  • .0823 km
  • .823 km
  • 82.3 km
sample how many mg are in 46 g
Sample: How many mg are in 46 g?
  • 46000 g
  • 4600 g
  • 460 g
  • 4.6 g
  • .046 g
section 3 scientific notation sig figs pages 46 52 rbqs pgs 59 61 21 23 36 46
Section 3: Scientific Notation & Sig FigsPages 46-52 RBQs Pgs. 59-61 #21-23, 36-46
  • When using conversion factors, the conversion factor has nothing to do with the number of significant figures.

Sample: What is the volume in mL of a substance that has a mass of 5.00 grams and a density of 2.1 g/mL?

section 4 units density and error pages 59 61 rbqs pgs 59 61 14 26 29 30 35 48 50
Section 4: Units, Density, and % ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50
  • Data can be either quantitative or qualitativeQuantitative:Qualitative:Quantitative data is data obtained through measurements
section 4 units density and error pages 59 61 rbqs pgs 59 61 14 26 29 30 35 48 501
Section 4: Units, Density, and % ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50
  • Every measurement needs a number and a unit
  • In chemistry, SIunitsare used to report measurement
section 4 units density and error pages 59 61 rbqs pgs 59 61 14 26 29 30 35 48 502
Section 4: Units, Density, and % ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50
  • Derived units can be made from the base units
  • These units include volume and density

1. What formula is used to find the volume of a cube?2. What units are used to measure a cube’s dimensions?3. Therefore, what are possible volume units?

section 4 units density and error pages 59 61 rbqs pgs 59 61 14 26 29 30 35 48 503
Section 4: Units, Density, and % ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50
  • Density is the ratio of an object’s mass to its volume
  • Mass measures the amount of matter present
  • Volume measures the space occupied by matter
  • And since a ratio is just a fraction

•What are some possible units for density?

slide68
Sample: A sample of liquid with a volume of 23.50 mL has a mass of 35.062 g. What is the density of this liquid?
  • 1.492 g/mL
  • 1.5 g/mL
  • .6702 g/mL
  • .67024 g/mL
  • 1.4920 g/mL
slide69
Sample: What is the volume of a sample of liquid mercury that has a mass of 76.2 g, given that the density of mercury is 13.6 g/mL?
  • 1.04 x 103 mL
  • 1.036 x 103 mL
  • 5.6 mL
  • 5.60 mL
  • 6 mL
section 4 units density and error pages 59 61 rbqs pgs 59 61 14 26 29 30 35 48 504
Section 4: Units, Density, and % ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50
  • Density can be usedto identify unknownsubstances
  • It can also be used todetermine if an objectwill float
section 4 units density and error pages 59 61 rbqs pgs 59 61 14 26 29 30 35 48 505
Section 4: Units, Density, and % ErrorPages 59-61 RBQs Pgs. 59-61 #14, 26-29, 30-35, 48, 50
  • Percent error is a measure of the accuracy of lab results. It indicates how far data is from the true value
sample a length is measured at 6 7 cm the correct value is 7 1 cm calculate the percent error
Sample: A length is measured at 6.7 cm. The correct value is 7.1 cm. Calculate the percent error.
slide73

Sample: A student measures the mass and volume of a substance and calculates its density as 1.40 g/mL. The correct value is 1.36 g/mL. What is the student’s percent error?

  • 42.86%
  • 29.41%
  • 28.57%
  • 40.00%