scientific measurement chapter 3.1 mr. hines
TRANSCRIPT
Scientific measurement Chapter 3.1 Mr. Hines Part A. The basics of measurement
Learning Targets I CAN
1 Define measurement and list different ways that the universe can be measured.
2 Associate different measurements with their proper units.
3 Analyze measurement as a function of Accuracy and Precision.
4 Explain the Reasons for Error in Measurement.
5 Calculate percent error.
Part B. Arithmetic of science and significant figures
6 Determine the numerical place value of whole numbers and decimal numbers.
7 Round numbers to the proper place value.
8 Make proper measurements using common tools in chemistry.
9 Estimate the uncertain digit.
10 Define significant figures and Explain why they are important.
11 Determine the significant figures in a measurement.
12 Add and subtract sig figs.
13 Multiply and Divide sig figs.
Part C. Powers of 10 and scientific notation
14 Recall basic knowledge about powers of 10
15 Define scientific notation, identify its parts, and explain why it is important.
16 Convert large numbers back and forth between scientific notation and standard form.
17 Convert small numbers back and forth between scientific notation and standard form.
18 Enter scientific notation into a calculator.
19 Multiply large and small numbers using scientific notation.
20 Divide large and small numbers using scientific notation.
Part D – Background Information About Conversions
21 Define conversion
22 Identify the different forms of conversions common in chemistry.
23 Identify the various units common in the English System.
24 Explain how the Metric system is organized with units.
25 Compare the metric system and the English system.
26 Identify abbreviations for measurements common in chemistry.
Part E – Calculations and Conversions
27 Perform unit conversions within the metric system.
28 Multiply fractions.
29 Understand mathematical cancellations.
30 Use dimensional analysis to convert back and forth between units in the English system and units in the metric
system.
31 Convert various units of temperature – English, metric, and SI.
32 Define Absolute Zero and explain how the Kelvin Temperature scale was developed.
Part F – Density
33 Describe/define density
34 Explain density as a measure of compactness.
35 Calculate the volume of various forms of matter including solid shapes – cube, sphere, irregular using the metric
system.
36 Explain the relationship between milliliters and cubic centimeters
37 Solve single variable algebraic equations
38 Calculate density
39 Calculate volume
40 Calculate mass
41 Explain density as a relationship between volume and particle spacing
42 Explain how objects of different sizes can have the same mass.
43 Explain how objects of the same size can have different masses.
44 Calculate the density of substances and predict which substances will float on which.
Vocabulary Parts A-C
Measurement Unit Mass Volume Accuracy Precision
Error Accepted value Chemistry Average Temperature English system
SI system Metric system Second Kelvin Celsius Fahrenheit
Gallon Liter Kilogram Gram Percent error Pound
Significant
figure
Uncertainty Experimental
value
Decimal
number
Proper place
value
Scientific
notation
Inclusive Trailing zeros Decimal Matter Figure Digit
Decimal places Place value Sig fig Sig dig Uncertain digit Dog
Coefficient Power of 10 Atom Standard form Convert Exponent
Energy Weight Percent Element Whole number Meniscus
Space Time Universe
Vocabulary Parts E-F
Conversion Measurement Unit float Density Meter Prefix
Length Dimensional
analysis
Conversion
factor
Cubic
centimeter
Irregular
shape
Absolute zero abbreviation
Joule Base unit Toe cube Numerator Denominator Nothing
Sphere Calorie Substance Compact Moon Solid Feet
Liquid Milliliter
Part A – THE BASICS OF MEASUREMENT
Target 1 - Define measurement and list different ways that the universe can be
measured. Pg 64
A. Measurement - a quantity that has both a number and a unit.
1. For example, how much do you weigh? _________________
2. In order for this to be a proper measurement, it must contain a number and a unit.
B. Science is very dependent on measurements.
C. Every time a scientist performs an experiment, something is being measured.
D. The four things in the universe are commonly measured in chemistry.
1. Matter – measured as mass or weight
2. Space – measured as volume
3. Energy – measured as temperature (energy has other measurements)
4. Time – measured as time
E. There is a very basic relationship between these 4 things in the universe. Energy moves matter through space
and it takes some time.
F. Everything everywhere is doing this.
Questions
1. What is a measurement? _______________________________________________________
2. What are the 4 measurements common in chemistry?
a) ______________ b) _____________ c) ______________ d) ______________
3. What is the relationship between these 4 things measured in chemistry?
_____________________________________________________________________________
Target 2 - Associate different measurements with their proper units. Pg 73 A. The universe can be measured using many units.
B. There are 3 systems for making measurements.
1. English System - used only in the United States
2. Metric System - Used around the world
3. SI System – Used around the world in science (SI stands for “System International”)
Universe Measurement English unit Metric unit SI unit
1. Matter
2. Space
3. Energy
4, Time
Target 3 - Analyze measurement as a function of Accuracy and Precision. Pg 64 A. Accuracy – the closeness of a measurement to the true value of what is being measured.
B. Precision – the reproducibility of a measurement when it is repeated.
Consider the example below:
© Copyright Pearson Prentice Hall
Measurements and Their
Uncertainty>
Slide
9 of 48
3.1 Accuracy, Precision, and Error
Target 4 - Explain the Reasons for Error in Measurement. Pg 64 A. Accuracy in measurements
1. All sciences rely on _________________.
2. Human beings of course are the ones who make the measurements.
3. Human beings are imperfect and make mistakes.
4. When mistakes are made, it is called _______________.
5. Error – mistake or accidental incorrectness
6. When humans make measurements, there are 2 factors that can cause error.
a. The ability to properly read a measuring tool
b. The quality of the measuring tool
B. These 2 scenarios can both lead to ERROR
1. Example 1: A person can have a very accurate measuring tool and not know how to use it
2. Example 2: A person can be very skilled at measuring, but have poor measuring tools
Questions
1. What is accuracy? ____________________________________________________________
2. What is precision? ____________________________________________________________
3. What is error? ________________________________________________________________
4. Describe the 2 scenarios that lead to error.
a. _____________________________________ b. _____________________________________
Target 5 - Calculate percent error. Pg 65
A. Percent error
1. Percent error - a calculation that determines the _______________ of a person’s measurement.
2. In other words, it can determine how “correct” or “incorrect” a measurement is.
3. There are 2 terms that you need to know in order to calculate percent error.
a. Accepted value
b. Experimental value
4. Accepted value – the correct value based on reliable information. Information listed on a label of
something is generally an accepted value.
5. Example, If you buy a gallon of milk, the container will say “1 Gallon” This is the accepted value.
6. Experimental value – a value that is measured in a lab (by you).
B. Calculations
1. When taking scientific measurements, human beings make errors. The amount of error can be
determined by simple mathematics.
2. This number should be written as a percent and gives a scientist an idea how accurate s(he) was.
For example: The known value for the Lab table was 829 cm. Jack Belittle measured the lab table to be 813 cm.
What is Jack’s percent error?
829 cm – 813 cm
___________________ x 100 = 1.93%
829 cm
**This says that Jack’s measurement was off by 1.93% (not bad)
Practice – Percent error Accepted Value Experimental value Percent error 1) 255 milliliters 271 milliliters
2) 78.4 grams 82.6 grams
3) .000624 grams .000425 grams
4) 10.1 meters 9.12 meters
5) .0675 liters .0758 liters
Questions
1. Define “accepted value” _____________________________________________________
2. Define “experimental value” ____________________________________________________
3. What do you think causes some percents to be negative?
_______________________________________________________________________
4. Kyle McIntyre is at Kroger and buys a gallon of orange juice. When he gets home, he measures the
volume of the orange juice with various tools around the house. His measurement says that he has 1.2
gallons of orange juice.
a. What is the accepted value? ___________________
b. What is the experimental value? ___________________
5. Calculate the percent error of Kyle’s measurement? Show your work.
PART B – THE ARITHMETIC OF SCIENCE AND SIGNIFICANT FIGURES
Target 6 - Determine the numerical place value of whole numbers and decimal
numbers. A. Number - an expression that represents “the counting of” (includes all digits)
B. Whole number – digits left of the decimal point
C. Decimal number – digits right of the decimal point (aka decimal place)
D. Place value – name of the place or location of a digit in a number
E. Figure – written symbol – usually a part of a number
F. Digit - written symbol – usually a part of a number
G. All figures (digits) will have a place value.
Example 1
Notes – label all words listed above
1234.5678
Example 2 9876.5432 Place value – Before the decimal figure Place value – After the decimal figure
Hundreds place
Tenth place
Tens place
Hundredth place
Ones place
Thousandth place
Questions
Example 2
8174.6352
1. What is the number listed in example 3? ______________
2. Which figure represents the hundreds place? _____
3. Which figure represents the tens place? ____
4. Which figure represents the ones place? ____
5. Which figure represents the tenth place? ____
6. Which figure represents the hundredth place? ____
7. Which figure represents the thousandth place? ____
8. What is the synonym for “figure?” _________________
Target 7 – Round numbers to the proper place value. A. Rounding numbers – process where the amount of figures in a number is properly shortened.
B. Proper place value – place value that you should round to.
C. There are 4 basic rules
1. The proper place value may or may not change
2. The figure that follows the proper place value will determine how to round.
3. Figures between 1 and 4 cause no change and are simply removed.
4. Figures between 5 and 9 will cause the proper place value to increase by 1.
Notes
Practice
Number Proper place
value
Answer Number Proper place
value
Answer
1
25.2
Ones 9
45.245
Hundredth
2
25.4
Ones 10
45.246
Hundredth
3
25.5
Ones 11
45.241
Hundredth
4
25.6
Ones 12
467.239
Hundredth
5
36.67
Tenth 13
467.239
Tens
6
36.65
Tenth 14
6.9
Ones
7
36.63
Tenth 15
7.59
Tenth
8
36.654
Tenth 16
27.567
Hundredth
Target 8 - Make proper measurements using common tools in chemistry. A. Tools for measurement in chemistry will measure the four things in the universe – matter, energy, space, and
time B. Reading a measuring tool properly takes _______________ and understanding.
C. In order to read a measuring tool properly, you must understand how the decimal system works.
D. For this reason, the metric system must be used for all scientific measurements because the metric system is
based on the ___________________.
E. All units in the metric system can be divided by 10. (English system is based on fractions).
F. To take a proper measurement from a lab tool, you must include one last digit past the smallest increment
marked on the lab tool.
G. Consider these examples - centimeters
1
Answer here
2
3
4
Target 9 - Estimate the uncertain digit. A. All measuring tools have _____________________.
B. Measuring tools can only measure to 1/10 of its smallest graduation.
C. For example, the measuring tool shown below can measure accurately to the ones and tenths place value.
D. It can also measure to the hundredths place based on the observer’s __________________.
E. The uncertain digit is estimated as 1/10 of the smallest graduation.
F. Uncertain digit – last digit in a scientific measurement that is ___________________.
G. A person’s ability to measure properly is called accuracy.
H. In order for a person to measure accurately, they must include an accurate uncertain digit.
Target 10 - Define significant figures and Explain why they are important. Pg 66
A. Significant figure– a count of all the digits that can be known accurately in a measurement, plus a last
estimated digit. (aka sig figs)
Ruler Z
_______________________
B. Lets assume that ruler Z (above) measures in centimeters.
C. It is counting in the ones place, is graduated to measure in the tenths place, and therefore is limited to a last
figure in the hundredths place. The measurement above would be 6.25 centimeters.
D. It is improper to write a number beyond the measurement capability of the measuring tool.
E. Therefore, a measurement like this ; 6.247 has too many figures. The seven is insignificant because the
measuring tool cannot measure to that place value.
F The seven would therefore be used to round the final measurement to 6.25.
G. Why are significant figures important?
1. Significant figures will eliminate unnecessary numbers after the decimal. For example, enter this into
your calculator – 153 / 7.23
2. You don’t need all of these numbers… where do you cut them off?
H. Significant figures are important because they express the accuracy of a measurement. (decimal place
value)
Questions
This is a thermometer that measures degrees Celsius.
1. What is the accurate measurement for this measuring tool? _________
2. What place value is the uncertain digit? _________
5. Draw your own line on the thermometer to represent a measurement of 31.7 degrees Celsius.
Target 11 – Determine the significant figures in a measurement.
5 Golden Rules of Significant Figures 1. All digits 1-9 inclusive are significant.
Example: 129 has 3 significant figures
2. Zeros between significant digits are always significant.
Example: 5007 has 4 significant figures
3. Trailing zeros in a number are significant only if the number contains a decimal point
Example: 100.0 has 4 significant figures.
100 has 1 significant figure.
4. Zeros in the beginning of a number whose only function is to place the decimal point are not
significant.
Example: 0.0025 has 2 significant figures.
5. Zeros following a decimal significant figure are significant.
Examples: 0.000470 has 3 significant figures
0.47000 has 5 significant figures.
Rule 1 Sig figs Rule 4 Sig figs 1 4 19 0.0034
2 27 20 0.0669
3 6722 21 0.00078
4 577 22 0.0034567
5 143644434 23 .000000007
6 5433 24 .000000976507
Rule 2 Rule 5 7 202 25 0.003400
8 4009 26 0.98000
9 609 27 .00990
10 5000566 28 .0099002
11 3090805 29 .030
12 700004002 30 .000040400
Rule 3 Review 13 200 31 .079
14 3000 32 400
15 200. 33 7008
16 800000. 34 .0004300
17 4000 35 466
18 4000. 36 .0098700
Target 12 –Add and subtract sig figs. Pg 68
RULE: When adding or subtracting, your answer can only show as many decimal places as the
measurement having the fewest number of decimal places. You must round to the proper place value.
Write the number of decimal places above each number and then perform the mathematics.
1) 4.60 + 3 =
7) 357.89 + 0.002
2) 0.008 + 0.05 =
8) 18.95 + 32.42 + 51 =
3) 22.4420 + 56.981 =
9) 5.5 + 3.7 + 2.97 =
4) 201 - 87.3 =
10) 4.675 - 3 =
5) 67.5 - 0.009 =
11) 75 - 2.55 =
6) 71.86 - 13.1 =
12) 11 - 9.9 =
Target 13 – Multiply and Divide sig figs.
RULE: When multiplying or dividing, your answer may only show as many significant digits as the
multiplied or divided measurement showing the least number of significant digits.
Write the amount of sig figs above each number and then perform the mathematics
1) 13.3 x 2.7 =
7) 50.0 x 2.00 =
2) 21.3 x 3.58 =
8) 2.3 x 3.45 x 7.42 =
3) 0.00003 x 727 =
9) 1.0007 x 0.009 =
4) 5003 / 3.781 =
10) 51 / 7 =
5) 89 / 9.0 =
11) 208 / 9.0 =
6) 5121 / 55 =
12) 0.0037 / 5 =
Re-run
1) 3.45 + 53.2529 + 0.601 =
5) 6.77 x 29.11 =
2) 74.160 - 4.8 - 0.470 =
6) 200.60 + 93 =
3) 2.15 x 3.11 x 121 =
7) 609.4443 / 82 =
4) 9634 / 6.002 =
203.3334 – 45.2 =
C. POWERS OF 10 AND SCIENTIFIC NOTATION
Target 14 - Recall basic knowledge about powers of 10.
Questions
1. Where is the decimal of all numbers if it is not written? ______________________________
2. What does a power of ten tell you to do with the decimal? ____________________________
3. Rewrite 10 x 10 x 10 with an exponent? ____________________________
Target 15 - Define scientific notation, identify its parts, and explain why it is
important.
A. Scientific notation – method for writing very large and very small numbers so that they are easier to
understand; shortcut for writing large and small numbers.
B. Scientific notation always contains 3 parts.
1. Coefficient
2. Power of 10
3. Exponent
In each example, Label the coefficient, power of 10, and exponent
Example 1
5.2 x 103
Example 2
3.7 x 107
C. One important rule about the coefficient – It must be a number equal to or greater than 1 and less than ten.
D. Scientific notation is the product of 2 numbers (2 numbers multiplied)
E. Scientific notation is based on powers of ten.
F. Scientific notation is important because it makes large and small numbers easier to understand.
Questions
1. What is scientific notation? ________________________________________________________
2. What are the 3 parts of scientific notation? ____________________________________________
3. Why is scientific notation important? ________________________________________________
4. What is the one important rule about the coefficient? ____________________________________
Target 16 - Convert large numbers back and forth between scientific notation
and standard form.
Put these numbers
in standard form Put these numbers into
scientific notation
1 3.9 x 103 6 30000
2 5.2 x 105 7 34000000
3 3.4 x 103 8 235000000
4 9.0 x 105 9 740000000000
5 1.43 x 109 10 500
Target 17 - Convert small numbers back and forth between scientific notation
and standard form.
Target 18 - Enter scientific notation into a calculator. A. Any scientific calculator will understand scientific notation if you use it correctly.
B. When entering scientific notation into a calculator, you must type in 3 things.
1. Coefficient
2. Power of 10
3. Exponent
C. In order to do this, you must find a special button on your calculator.
D. This button is called “the power of 10” button.
E. There are 2 common ways that calculators label this button. EE EXP
F. Look for these buttons on your calculator. It should have one or the other, not both.
G. Once you have found the “power of 10” button, write the label here ________
H. There are 3 steps
1. Type in the coefficient
2. Hit the “power of 10” button
3. Type in the exponent
I. Type this number into your calculator. 4.45 x 101
Target 19 - Multiply large and small numbers using scientific notation.
Notes
A. In order to multiply large numbers, you will need your calculator.
B. This is best learned by doing – Perform these exercises
C. Coefficients will determine sig figs.
1 [6.84 x 103] x [4.54 x 10
6]
2 [2.0 x 10 11
] x [8.5 x 105]
3 [4.42 x 10-6
] x [8.67 x 10-7
]
4 [3.7 x 10 9
] x [7.3 x 10-2
]
5 [8.77 x 1015
] x [3.714 x 1019
]
6 [5.0 x 10 -2
] x [7.85 x 1014
]
7 [1.042 x 10-11
] x [4.002 x 10-15
]
Important – There are other methods for performing this task on your calculator. In order to keep things
simple, only one method will be taught. Most of the time, when students use other methods, they get wrong
answers. You are strongly urged to use the method taught in class.
Target 20 - Divide large and small numbers using scientific notation. 1 [2.21 x 10
13] ÷ [1.44 x 10
3]
2 [1.92 x 10
-2] ÷ [2.3 x 10
8]
3 [9.4 x 10
2] ÷ [1.24 x 10
-9]
4 [9.2 x 10
-3] ÷ [6.3 x 10
16]
5 [2.4 x 10
6] ÷ [5.49 x 10
-9]
6 [4.5 x 10
9] ÷ [2.45 x 10
-4]
7 [3.6 x 10
-6] ÷ [2.1 x 10
15]
If your calculator is not working, here is how you do it by hand – to save time, this will not be taught in class, but
after school by request.
Rule for Multiplication - When you multiply numbers with scientific notation, multiply the coefficients together
and add the exponents. The base will remain 10.
Rule for Division - When dividing with scientific notation, divide the coefficients and subtract the exponents.
The base will remain 10.
Part D – Background Information about Conversions
Target 21 - Define conversion A. Conversion - method where a measurement is rewritten using different units.
B. For example – If you measure the length of a cube to be 8.35 centimeters, you can calculate how many inches
this would be – this is a conversion (centimeters to inches)
C. Using the ruler above, perform the following conversions
English unit (inches) Metric unit
(centimeters)
English unit
(inches)
Metric unit
(centimeters)
1 1.00 inch
4 1.50 inches
2 2.00 inches
5 3.50 inches
3 3.00 inches
6 4.00 inches
Target 22 - Identify the different forms of conversions common in chemistry. A. There are 3 kinds of conversions that we will study
1. Metric to Metric
2. Metric to English (and in reverse)
3. SI to English (and in reverse)
Target 23 – Identify the various units common in the English System. A. Mass – pounds, ounces
B. Volume – Gallons, quarts, pints, cups, tablespoons, fluid ounces, etc
C. Energy – Fahrenheit (temperature)
D. Time – seconds, minutes, hours
Target 24 – Explain how the Metric system is organized with units.
Metric system *This chart can be expressed with reverse exponents depending on the mathematical point of view
Giga Mega Kilo Hecto Deca Base Deci Centi Milli Micro nano
G M k h da Gram
Liter
Joule
Meter
d c m µ n
1000 100 10 1 .1 .01 .001
109 10
6 10
3 10
2 10
1 10
0 10
-1 10
-2 10
-3 10
-6 10
-9
A. The base units represent measurements counting in the “ones” place.
B. Prefixes of the base units will determine to which decimal place value is being expressed.
C. What is a prefix?
1. A prefix is a description that comes before a metric base unit.
2. For example – centimeters – “centi” is the prefix for the base unit “meter”
3. Centi means “one hundredth”
4. Therefore, 1 centimeter is 1 hundredth of a meter (remember that 1 cent is one hundredth of dollar.)
D. Common metric prefixes include kilo, centi, milli, …others
E. Here are some metric base units that we will study in chemistry
1. Mass - grams
2. Volume - Liters
3. Energy –Celsius, Calories, Joules, Kelvins (all measurements of energy)
4. Time – seconds
Target 25 – Compare the metric system and the English system. A. Compare – explain how 2 things are similar and different.
Venn Diagram
Target 26 – Identify abbreviations for measurements common in chemistry.
Mass
Abbrev Volume
Abbrev Energy
Abbrev Time
Abbrev
Pound Gallon Joule Hour
Ounce
Fluid
Ounce
Calorie Minute
Gram
Liter Fahrenheit Second
Kilogram
Kiloliter Celsius millisecond
Milligram
Milliliter Kelvin microsecond
Part E – Calculations and Conversions
Target 27 - Perform unit conversions within the metric system Thumb rule
Giga Mega Kilo Hecto Deca Base Deci Centi Milli Micro nano
G M k h da d c m µ n
Giga Mega Kilo Hecto Deca Base Deci Centi Milli Micro nano
G M k h da d c m µ n
A. Mass 1. What is the metric base for measuring mass? ___________________
2. What is mass a measure of? ______________________
1. 25 kg
g
7. 3.00 µg
dg
2. 753 g
kg
8. 40.09 dag
kg
3.
1021 mg
kg
9. 45 mg
kg
4.
468.3 mg
g
10. 43.56 mg
µg
5.
2.67 kg
mg
11. .0633 kg
Mg
6.
454 mg
g
12. 21.55g
mg
Questions
1. How many grams are in 1 kilogram?______________________
2. How many milligrams are in 1 gram?_____________________
3. How many milligrams are in 1 kilogram?__________________
4. Name an object that weighs about 1 gram. ___________________
5. Name an object that weighs about 1000 milligrams. _________________
6. Name an object that weighs about 1 kilogram. __________________
B. Volume What is the metric base unit for measuring volume?__________________
What is volume a measure of? _________________________________
1. 37 Liters
mL
7. 1.2 dL
mL
2. 7088 mL
L
8. 1499 mL
hL
3.
45 kL
L
9. 7.3 ML
L
4.
333 L
kL
10. 45.7 GL
kL
5.
5 kL
mL
11. 44 kL
mL
6.
60 000 mL
kL
12. 4 000 000 mL
µL
Questions
1. How many liters are in 1 Kiloliter?______________
2. How many milliliters are in 1 liter?______________
3. Name an object that has a volume of about 1 liter.______________
4. Name an object that has a volume of about 1 milliliter._______________
5. Name an object that has a volume of about 1 kiloliter._______________
All together now 1. 23.6mg
g
7. 77 kL
daL
2. 33.6 L
mL
8. 5.5 kg
hg
3.
.006 kL
mL
9. 23.6 L
µL
4.
10 Gg
mg
10. 86.2 µL
mL
5.
3.1 g
mg
11. .867 µg
mg
6.
56 L
µL
12. 45 kg
Mg
Questions
1. The mass of a potato is measured in _____________.
2. The amount of water in a beaker is measured in _____________.
3. The length of a table is measured in ______________.
4. A 2.0 liter bottle of Mountain Dew is how many mL?_________________
5. A 5.0 gram vitamin pill is how many milligrams? _________________
Targets 28-30 Skipped for now
Target 31 - Convert various units of temperature – English, metric, and SI
A. Celsius and Fahrenheit
(ºF – 32) x .56 = ºC (ºC x 1.8) + 32 = ºF
Notes
Perform the conversions
1 Convert 77.1 ºC to ºF
6 Convert - 42.4 ºCelsius to
ºFahrenheit
2 Convert 58.6 ºC to ºF
7 Convert 55.0 ºFahrenheit to
ºCelsius
3 Convert 11.0 ºF to ºC 8 Convert -68.5 ºCelsius to
ºFahrenheit
4 Convert 101.2 ºF to ºC
9 Convert 2.6 x 102 ºF to C
5 Convert 97.6 ºF to ºC
10 Convert 0.11 ºC to º F
B. Celsius and Kelvin
K = ºC + 273 ºC = K - 273
a. Convert degrees Celsius to Kelvins - add 273 to the Celsius temperature.
Example - Convert 44 ºC to Kelvins. 44 + 273 = 317 K (Kelvins)
b. Convert Kelvins to degrees Celsius – subtract 273 from the Kelvin temperature
Example – Convert 434 Kelvins (K) to degrees Celsius 434 – 273 = 161 ºC
Perform the conversions
1 Convert 45.1 ºC to Kelvins
6 Convert 62.5 ºC to K
2 Convert 22.6 ºC to Kelvins
7 Convert 442.0 K to ºC
3 Convert 442.0 Kelvins to ºC 8 Convert -88.5 ºC to K
4 Convert 97.2 Kelvins to ºC 9 Convert 2.6 x 102 ºC to K
5 Convert 77.2 Kelvins to ºC 10 Convert 0.0 K to º C
Target 32 – Define Absolute Zero and explain how the Kelvin
Temperature scale was developed. A. Each winter, some parts of the world experience cold weather.
B. Water freezes, it snows, and people must wear more clothing in order to remain warm.
C. Humans usually consider 0 ºC to be a cold temperature. (this is the freezing point of water)
D. How much colder can it get? Is there a “lowest temperature?”
E. Yes, there is a lowest temperature – it is called ABSOLUTE ZERO.
F. Absolute Zero is -273 ºC (it can’t get any colder than this)
G. Scientists decided to create a new temperature measurement system that did not have any negative numbers.
H. They decided that absolute zero would be the bottom – and set -273 º C as zero Kelvins.
I. In other words, the Kelvin temperature scale has no negative numbers. This becomes useful in chemistry.
J. Absolute zero = zero Kelvins (0 K).
K. Therefore, in order to convert Celsius to Kelvins, you simply add 273. to the Celsius temperature
Questions
1. What is the coldest temperature using the Celsius Scale? ________
2. What is the coldest temperature using the Kelvin Scale? ________
3. How do you convert Celsius to Kelvin? ________________________________________________
4. How do you convert Kelvin to Celsius? ________________________________________________
5. Why is is the Kelvin scale useful in chemistry? __________________________________________
PART F - DENSITY
Target 33 - Describe/define density.
A. There are several ways of describing density
1. Density is the relationship between an object’s mass and ________________
2. Density can be calculated by dividing an object’s mass by its volume.
D = M / V or Density = Mass / Volume
3. Density will have __ units – mass and volume.
a. For example, the density of quartz is 19.30 grams/milliliters
4. Any sample size of the same substance will have the same _________________.
a. Example: a liter of water will have the same density as a swimming pool of water.
5. Density can also be a description of how _____________ a sample of matter is.
6. A substance of lesser density will always float on a substance of greater density.
a. Example: oil floats in water – therefore, oil is less dense than water.
Target 34 - Explain density as a measure of Compactness (Page 90)
A. What is meant by compact?
B. Remember that ______________ is anything made of atoms.
C. Atoms can be squeezed together to occupy less space (less volume).
D. When the volume of matter is squeezed together, it is more compact.
1. Example – You can squeeze a pillow to a smaller volume – the squeezed pillow would be
considered more compact than a pillow left unbothered. However, the squeezed pillow would
have the _________________ as the unbothered pillow. Therefore the compact pillow is more dense.
2. More compact = more dense.
3. If atoms are closer together, they occupy less space (more compact)
Questions
1. What can you say about atoms that are squeezed together?
___________________________________________________________
2. What is meant by the term “compact?”
___________________________________________________________
3. Allyson Tyra squeezes a sponge and it becomes smaller. What can be said about the density of the sponge
after she squeezed it? _______________________
4. How many units will a measurement of density have? ______
Target 35 - Calculate the volume of various forms of matter including solid
shapes – cube, sphere, irregular - using the metric system.
A. Calculating the volume of a liquid is easy, just pour the liquid in a graduated cylinder and read the
graduations.
B. Calculating the volume of a solid is more challenging; you have to know the dimensions.
C. We will measure (calculate) the volume of 3 shapes.
1. Cube/rectangular box
2. Sphere
3. Irregular
Calculate the volume of a rectangle or cube. Formula --
- Volume = L x W x H
Calculate the volume of a sphere. Formula --- Volume
= 4/3πr3
Length =4.05 cm
Width = 3.75 cm
Height=3.50 cm
Radius = 2.25cm
Measure the volume of an irregular shape
Notes
Target 36 - Explain the relationship between milliliters and cubic centimeters
(page 89)
1 milliliter = 1 cubic centimeter OR 1 mL = 1cm3
Notes
Questions:
1. How many cubic centimeters is 10 milliliters? ___________
2. How many cubic centimeters is 323.3 milliliters? _________
3. How many milliliters is 34 cubic centimeters? ___________
4. How many milliliters is 88.9 cubic centimeters? _________
5. What is the abbreviation for cubic centimeters? __________
6. What is the abbreviation for milliliters? _________
7. How many cm3 is 37 ml? ________
8. How many ml is 126.2 cm3? _______
Target 37 - Solve single variable algebraic equations
Notes
Target 38 - Calculate density (Page 90) A. Calculating density requires the following equation
D = M / V or Density = Mass / Volume
B. Just like in Algebra, you replace letters with appropriate numbers.
C. Whenever you are asked to calculate density, you will be given mass and volume.
Notes
Examples;
1. Zach Busse has a cube with a
mass of 244 grams and a volume
of 103 milliliters. What is the
density of the cube?
2. Laura Kaufman has a rock with
a mass of 912.0 grams and a
volume of 755.2 milliliters. What
is the density of the cookie dough?
3. Caleb Hale has a ball of cookie
dough with a mass of 25 grams
and a volume of 75 milliliters.
What is the density of the rock?
4. Place the objects in order from lowest density to highest density.
Low Medium High
Target 39 - Calculate volume (Page 92) A. When calculating the volume of an object, you must know the density and the mass.
B. Calculating Volume uses the same equation as used above.
Notes
Examples
1. Nicole Ferrara has a marble
with a density of 2.61 grams per
milliliter (g/mL) and a mass of
101 grams. What is the volume of
the marble?
2. David Jones has a basketball
with a density of .896 g/mL and a
mass of 241 grams. What is the
volume?
3. Brittany Moeckel has a steel
bowling ball with a density of 7.81
g/mL and a mass of 802 grams.
What is the volume of the ball?
4. Place the objects in order from lowest volume to highest volume.
Low Medium High
Target 40 - Calculate mass (Page 92) A. When calculating the Mass of an object, you must know the density and the volume.
B. Calculating Mass uses the same equation as used above.
Notes
Examples
1. Audra Johnson has a brass
statue with a density of 8.40 g/mL
and a volume of 69 milliliters.
What is the mass?
2. Ryan Smith has a quartz crystal
with a density of 4.31 g/mL and a
volume of 209 milliliters. What is
the mass?
3. Taylor Johnson has ball of
modeling clay with a density of
1.67 g/mL and a volume of 562
milliliters. What is the mass?
4. Place the objects in order from lowest mass to highest mass.
Low Medium High
Complete the table – mind your sig figs
Substance Mass (grams) Volume (milliliters) Density (g/mL)
Gold
.301mL 19.3 g/mL
Table sugar
.960g 1.59 g/mL
Gasoline
3.22g 4.29mL
Target 41 - Explain density as a relationship between volume and particle spacing.
Models of density – the cube
Target 42 - Explain how objects of different sizes can have the same mass (Page 89)
Calculate the density for each cube.
Questions
1. Calculate the density for each cube – write your answers in the table above.
2. How can the objects above have the same mass if they are different sizes?
_____________________________________________________________________
3. Genius question - Convert the volume of each substance above to milliliters.
Lithium ____ mL
Water ____ mL
Lead ____ mL
Target 43 - Explain how objects of the same size can have different masses.
A. Objects of the same size can have different masses because of particle spacing – when the spaces between
particles are small, more particles can fit.
B. Which cube is more dense? How do you know? ___________________________________________
Target 44 - Calculate the density of substances and predict which substances
will float on which. A. Remember from earlier that a substance of lesser density will always float on a substance of greater density.
B. Example: oil floats in water – oil is less dense than water.
Example 1 - Predict which substance will float on which.
Mass (grams) Volume (milliliters) Density (g/mL)
Substance A 25.0 g 50.0 mL
Substance B 50.0 g 25.0 mL
Which will float on which? _____________________________________________________________
Mass (grams) Volume (milliliters) Density (g/mL)
Substance C 22.60 g 34.35 mL
Substance D 87.95 g 77.77 mL
Substance E 37.38 g 34.00 mL
Which will float on which? __________________________________________________________