1,the study of change
TRANSCRIPT
![Page 1: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/1.jpg)
Chemistry: The Study of ChangeChemistry: The Study of Change
Chapter OneChapter One
1
![Page 2: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/2.jpg)
What is Chemistry?The science of studying matter, its composition, properties, the changes it undergoes, and the energy associate with these changes.
Chemistry is called the central science, because a basic knowledge of chemistry is essential for students of biology, physics, geology…..and many other subjects
Why study ChemistryWhy study Chemistry•Explain the natural worldExplain the natural world ,….Why? ,….Why? e.g.: -how the battery of your car works, e.g.: -how the battery of your car works, - why the color of leaves of trees change in autumn….ect.- why the color of leaves of trees change in autumn….ect.
you can answer these questions and others by understanding some you can answer these questions and others by understanding some chemistrychemistry
you are able to read and understand this sentence because chemical you are able to read and understand this sentence because chemical reactionsreactions occur in your brain.occur in your brain.
2
![Page 3: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/3.jpg)
The food you ate is furnishing energy through The food you ate is furnishing energy through chemical reactionschemical reactions Trees and grass grow because of chemical reactionsTrees and grass grow because of chemical reactions•Prepare for a careerPrepare for a career
IndirectlyIndirectly - problem solving and thinking skills- problem solving and thinking skills•AgricultureAgriculture
ProductionProduction - fertilizers, soil tests- fertilizers, soil testsProtectionProtection – pesticide, herbicide – pesticide, herbicide
•MedicineMedicineDrugsDrugsMaterials- hips, artificial skinMaterials- hips, artificial skinBiotechnology- using organisms as a Biotechnology- using organisms as a means of means of
productionproduction
3
![Page 4: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/4.jpg)
•Environment- PollutionEnvironment- PollutionEliminate sourcesEliminate sourcesTreatment once pollutedTreatment once polluted
•AstronomyAstronomy Remote analysis of stars from their Remote analysis of stars from their lightlight Analysis of extraterrestrial samplesAnalysis of extraterrestrial samples
4
![Page 5: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/5.jpg)
Scientific method science: is a framework of gaining and organizing knowledge
science: - a set of facts - a plan of action ( a procedure for processing and understanding certain type of information)
Scientific thinking is useful in all aspect of life. The process that lies at the center of scientific inquiry is called the scientific method.
The scientific method: A way of solving problems and answering question, or a systematic approach to research
5
![Page 6: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/6.jpg)
Steps of scientific methods:1. Observations- what is seen or measured
it can be
qualitative quantitative (general observations (comprising numbers obtained about the system; by various measurements of system; water is liquid, sky is blue) water is boil at 100°C)
2. Hypothesis- a possible explanation of observation, based on research and previous knowledge.
3. Experiment- designed to test hypothesisonly two possible answers: hypothesis is right…….hypothesis is wrong…..
6
![Page 7: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/7.jpg)
Experiment always produce new observations and this bring the process back to the beginning again…generate new data observations from experiment modify hypothesis repeat the cycle.The cycle repeat many times by you and by others, hypothesis gets more and more certain, becomes a theory.Theory: a set of tested hypotheses that gives an overall explanation of some natural phenomenon( explain why things behave a certain way). Theories have predictive value.The true test of a theory is if it can predict new behaviors.If the prediction is wrong, the theory must be changed.Theory can never be proven, it is the best explanation.
7
![Page 8: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/8.jpg)
if the same observations applies to many different systems…scientific law is developed.Law: describe how things behaves, summaries of observation (usually mathematical equations between phenomena that is always the under the same conditions)…equation of how things changeSo law…how theory….why
8
![Page 9: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/9.jpg)
Observations
Hypothesis
Experiment
Law
Theory(Model)
Prediction
Experiment
Modify
9
![Page 10: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/10.jpg)
Classifications of Matter
Matter: anything that occupies space and has mass.
There are some fundamental ways in which matter is classified, the most important of these are:
1) according to its physical state:
All substances can exist in three states, which are liquid, solid, and
gas.
gas state:gas state: - no fixed volume and shape
- take the shape and volume of the container
- can be compressed
- their molecules far apart and move fast
10
![Page 11: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/11.jpg)
liquid state: - has distinct volume
- no specific shape (take the shape of the container)
- can not be compressed
- close to each other but are not held so rigidly in position and can move past one another
solid state: - has definite shape and volume
- rigid in shape.
- can not be compressed
- held close to each other with little freedom of motion
The following figure shows the three states of matter, it can be interconvert without changing its composition
11
![Page 12: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/12.jpg)
Solid Liquid Gas
Melt Evaporate
CondenseFreeze
12
![Page 13: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/13.jpg)
2) According to its composition:
Pure substance mixture
elements compoundsHomogenous
mixtureHeterogeneous
mixture
13
![Page 14: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/14.jpg)
Elements:
- simplest kind of matter, cannot be separated into simpler substances by chemical means.
- building blocks for all complex
- about 117 elements are known. Most of them occur naturally on earth. The others have been created by scientists via nuclear process.
- building blocks of elements are atoms
- the same type of elements combine to for molecules
e.g.: O2 , Cl2 , N2 …ect
Compounds:
- Forms due to interaction of two or more elements chemically united in fixed proportions. e.g.: H2O, NaCl , Na2CO3 ….ect
- Unlike mixtures, compounds can be separated only by chemical means into their pure components
14
![Page 15: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/15.jpg)
mixture:� A combination of two or more substances.� Variable composition.� each substance retain its own chemical identity and its own
properties. Examples: air, soft drink, milk …
a) Heterogeneous mixture
- mixture is not the same from place to place.
- consist of two phases - e.g.: soil, oil and water
b) Homogeneous mixture (solution) - same composition throughout. therefore uniform properties
- Every part keeps its properties.
- consist of a single phase. - e.g.: air, salt dissolved in H2O
Any mixture can be separated by physical means into pure components without changing the identities of the components.
15
![Page 16: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/16.jpg)
Physical and Chemical Properties of matterEvery substance has a unique set of properties that allow us
to recognize it and distinguish it from other substances.
e.g: water: state: liquid, m.p.=0°C , b.p=100°C , density=1g/ml , flammability: no
Properties of matter can be grouped into two categories:
1) physical properties
2) chemical properties
16
![Page 17: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/17.jpg)
Physical properties: It is the one that can be measured or observed without changing
the composition or identity of substance. e.g.: color, m.p., b.p., state of matter, viscosity …ect these physical can be divided to: Extensive Properties - only depends on the amount of matter,
e.g: mass, volume, length as the amount of substance increase, these properties increaseValues of the same extensive property can be added together. Intensive Properties - only depends on the type of matter, not the amount. e.g.: state of matter, color, melting point, boiling point . … do not depend on the amount
of substance.Values of the same intensive property are not additive
17
![Page 18: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/18.jpg)
The ratio of two extensive properties will give an intensive properties.
example: the density (d), which is the ratio of mass to volume
d =
� The SI- derived unit for density is kg/m3. This unit is large for most chemical applications. Therefore, (g/cm3) and its equivalent (g/mL) are used for solid and liquid densities. Because gas densities are very low, we express them in (g/L)
� Useful for identifying a compound� Useful for predicting weight
mV
Extensive property
Extensive property
18
![Page 19: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/19.jpg)
1.0 g/cm3 = 1.0 g/mL = 1000kg/m3
1.0 g/ L = 10-3 g/mL
The following table lists the densities of several substances:
substance Density (g/mL(Air .0 001
Ethanol .0 79Water .1 00
Mercury .13 6Table salt .2 2
Iron .7 9Gold .19 3
Osmium .22 6
19
![Page 20: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/20.jpg)
Example:
� carbon tetrachloride (density 1.53 g/cm3 ) weighs 161.9 g. What is the volume of the carbon tetrachloride ?
d = m / V V = m / d
V = 161.9 g / 1.53 (g/cm3)
V = 105.82 cm3
Example:
� A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass
d =mV
m = d x V = 21.5 g/cm3 x 4.49 cm3 = 96.5 g
20
![Page 21: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/21.jpg)
physical changes: A change that changes appearances, without changing the
composition. e.g: water change from solid to liquid to vapor
Chemical properties: is the tendency of a substance to undergo a particular chemical reaction.
e.g: flammability, reactivity toward acids
Chemical changes A change where a new form of matter is formed. Also called
chemical reaction. Alter not only the physical appearance but also the chemical makeup
as well
21
![Page 22: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/22.jpg)
Units of measurements
Making observations is fundamental of all science.
Quantitative observation or measurement, always consists of two parts:
- Number - Scale (unit)
Any measured value must contain both parts to be meaningful. Two major systems of measurements are adopted in different parts of the world: 1)English system: used in U.S.A. length…yard, feet, inch. mass….tons, pounds, ounces volume…gallon, quarts, pints2)International System of Units (abbreviated SI)
(le System International) based on the metric system. used by most of the rest of the world and in science.
22
![Page 23: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/23.jpg)
The SI system specify a set of seven basic units which are:
Physical quantity Name of unit symbol
Mass kilogram kg
Length meter m
Time second s
Temperature Kelvin K
Electric current ampere AAmount of substance mole molLuminous intensity candela cd
23
![Page 24: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/24.jpg)
Derived units
The SI units seems to be very limited, there are many quantities such as area, volume, speed whose units don’t appear in the previous table.
In the SI system, units of such quantities are obtained by appropriate combination of the base unit and called the derived unit.
Examples:Area = length x width = m (base unit) x m (base unit) = m2
speed = distance/time = m (base unit)/s (base unit) = m/s force = mass x acceleration
= mass x [distance/(time)2 ] = kg x m/s2
24
![Page 25: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/25.jpg)
Because the fundamental units are not always convenient (e.g: expressing the mass of a pen in kg), prefixes are used to change the size of the unit.
Some of these prefixes a listed in the following table:
25
![Page 26: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/26.jpg)
prefix symbol meaning Exponential notation
mega M 1,000,000 106
kilo k 1,000 103
hecto h 100 102
deka da 10 101
- - 1 100
deci d 0.1 10-1
centi c 0.01 10-2
milli m 0.001 10-3
micro µ 0.000001 10-6
nano n 0.000000001 10-9
pico p 0.000000000001 10-12
26
![Page 27: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/27.jpg)
prefix factor example
kilo 1000 (103) 1.0kilometer (km)= 103m1.0 kilogram (kg) = 103g
milli 1/1000 (10-3) 1.0millisecond(ms)=10-3s1.0milligram (mg) = 10-3g
centi 1/100 (10-2) 12.5 cm = 12.5x10-2m
pico 10-12 7.91x109 pg =7.91x109x10-12g =7.91x10-3g
27
![Page 28: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/28.jpg)
Uncertainty in measurementThe number associated with a measurement is obtained using some measuring device.
For example, consider the measurement of the length of an object.
21 3 4 5
28
![Page 29: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/29.jpg)
Note that the length of the object occurs at about 4.55 cm.note that we must estimate the last number by interpolating between the 0.1 cm marks. Since the last number is estimated, its value may be different if another person makes the same measurement. If several persons make the same measurement, they obtain the following values: 4.54 cm, 4.56 cm,..ect.These results show that the first two numbers (4.5) remain the same ..called certain digits The digit to the right of the (5) must be estimated and therefore varies; it is called an uncertain digit.
29
![Page 30: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/30.jpg)
Any measured value contain : certain digits + uncertain digit. These numbers are called the significant figures of a measurement.Measurement always has some degree of uncertainty,
which depends on the precision of the measuring device. Example: consider the measuring the same object by using the following meter… its length will be 4.6 or4.5 or 4.7 or 4.4 …( 4 is certain), (6, 5, 7, 4 uncertain)
21 3 4 5
30
![Page 31: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/31.jpg)
The convention of sig. fig. automatically indicate something about the uncertainty in measurement. The uncertainty in the last number is usually assumed to be ± (smallest marks /2)In the previous examples: ± 0.1/2 =0.05
± 1/2 = 0.5 example: what is the length of the following object
100 200150 25050
142 (± 5) cm
certain uncertain
uncertainty
31
![Page 32: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/32.jpg)
Significant figures and calculations
Rules for counting sig. fig.:1) Nonzero integers: always count as sig. fig.
e.g: 234 cm 3 sig. fig., 4.742 g 4 sig. fig.2) Zeros: there are three classes of zeros
a) leading zeros: zeros that precede the nonzero digits, do not count as sig. fig., their purpose is to indicate the placement of decimal point e.g.: 0.23 2 sig. fig.; 0.00432 3 sig. fig.b) captive zeros: zeros between nonzero digits
count as sig. fig. e.g. 1.08 3 sig. fig. ; 3.0502 5 sig. fig.
32
![Page 33: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/33.jpg)
c) trailing zeros: zeros at the right end of the number.
They are significant only if the number contains a
decimal point e.g.: 2.0 mg 2 sig. fig.
For numbers that do not contain decimal point, (zeros after the last nonzero digit) may or may not be significant,
400. 3 sig. fig. , 400 1 sig. fig.
3) Exact numbers: determine by
- counting: 3 apples, 10 students…
- definition: 1 inch = 2.54 cm
they do not considered in as sig. fig.
33
![Page 34: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/34.jpg)
Scientific notation:
If the length of an object is 150 cm, is the zero consider as sig. fig. or not ?
It depends on the measuring device used as shown in the following example:
34
![Page 35: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/35.jpg)
100 200150 25050
100 200
140 cm
certain uncertain
(3 sig. fig.)
140 cm
certainuncertain
(2 sig. fig.)
Uncertainty ±5
Uncertainty ±50
35
![Page 36: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/36.jpg)
Note the number 140 can be written in exponential notation :
the first measuring device : 1.40 x 102 (3 sig. fig.) the second measuring device: 1.4 x 102 (2 sig. fig.)This type of notation has at least two advantages - indicate the no. of sig. fig. easily - fewer zeros are needed to write a very large and a very
small number.e.g.: 0.000060 represent as 6.0 x 10-5
660000 represent as 6.6 x 105 ( 2 sig. fig.) 6.60 x 105 (3 sig. fig.)
6.600 x 105 (4 sig. fig.)
36
![Page 37: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/37.jpg)
Problem500 is only 1 significant figure.
if it really has three, how can I write it?
Three ways to write it:� 500.� 500 (± 5) � In scientific notation: 5.00 x 102
now the zero counts.
If it contain two sig. fig.:
5.0 x102 or 500 (± 20)
37
![Page 38: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/38.jpg)
Example(1): How many sig figs in the following measurements?
� 458 g (3)� 4085 g (4)� 4850 g (3)� 0.0485 g (3)� 0.004085 g (4)� 40.004085 g (8)
� 405.0 g (4)� 4050. g (4)� 0.450 g (3)� 4050.05 g (6)� 0.0500060 g (6)
38
![Page 39: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/39.jpg)
Example (2): write the following measurements in scientific notation to the correct number of sig. fig.
- 67000 (to 3 sig. fig.) = 6.70 x 104
- 67000 (to 2 sig. fig.) = 6.7 x 104
- 0.00009010 = 9.010 x 105
Example (3): (3): how many sig. fig. in the following number
- 896000 (± 100), it contains (4 sig. fig.)
uncertaintyScientific notation= 8.960 x 105
39
![Page 40: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/40.jpg)
Rules for sig. fig. in mathematical operations
� For addition and subtraction:
The result has the same number of decimal places as the least precise measurement used in calculation. For example:
12.11
18.0 one decimal places
1.013
31.123 correct 31.1
e.g: 27.93 + 6.4 = 34.3
45.86 – 32.467 = 13.393 = 13.40
+
+
40
![Page 41: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/41.jpg)
� For multiplication and division:
The number of sig.fig. in the result is the same as the number in the least precise measurement used in the calculation. For example:
4.56 x 1.4 = 6.38 correct 6.4
e.g : 6.56 x 8.215 = 53.8904 = 54.0
(3.97 x 5.870) / 2.1 = 0.332057… = 0.33
3 sig. fig. 2 sig. fig. 2 sig. fig.The product should have only two sig. fig.
41
![Page 42: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/42.jpg)
Practice� 4.8 + 6.8765 = 11.7 � 520 + 94.98 = 615� 0.0045 + 2.113= 2.118� 500 -126 = 374� 6.0 x 103 - 3.8 x 102 = 5.6 x 103
� 6.0 x 10-2 - 3.8 x 10-3 = 5.6 x 10-2
� 5.33 x 1022 - 3.8 x 1021 = 5.0 x 1022
� 4.5 / 6.245 = 0.72� 4.5 x 6.245 = 28� 9.8764 x 0.043 = 229.6837… = 230 or 2.3 x 102
� 3.876 / 1980 = 0.001957575… = 0.001958
42
![Page 43: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/43.jpg)
Practice� 4.184 x 100.62 x (25.27 – 24.16) =
4.184 x 100.62 x 1.11 = 467.3034288
= 467
• 9.2 x 100.658.321 + 4.026
= 74.996355.. = 75
• 1.00866 – 1.00728
6.02205 x 1023= = 2.29 x 10-270.00138
6.02205 x 1023
43
![Page 44: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/44.jpg)
Rounding rules
� Look at the number behind the one you’re rounding.
� If it is 0 to 4 don’t change it.� If it is 5 to 9 make it one bigger.� Round 45.462 to four sig figs.:� to three sig figs.:� to two sig figs.:� to one sig figs.:
45.46
45.5
4550
44
![Page 45: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/45.jpg)
Units for lab. measurements
In chemistry, it is necessary to measure mass, volume, length, and temperature.
Length: The SI unit is meter (m), we use smaller units for length in lab. which are cm and mm.
1 cm = 10-2 m or 1 m = 100 cm 1mm = 10-3 m or 1m = 1000mm
1 cm = 10 mm
45
![Page 46: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/46.jpg)
Mass and Weight� Mass: amount of matter in an object.
Mass is a measure of the resistance of an object to change in its state of motion
� Weight: the response of mass to gravity.
weight measure the force with which the object of a given mass is attracted by gravity.
� Sometimes used interchangeably� Mass can’t change, weight can� Your mass on the earth is the same as your mass on the moon, but
your weight will be differ.� SI unit for mass is kg (the only base unit that contain prefix, kilo).� In the lab. We use the unit of gram, (g) (1.0 kg = 103 g)
we use the balance to measure the mass.
46
![Page 47: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/47.jpg)
� Volume: it is not a fundamental SI unit, it is a derived unit from the length.
A cube that measure 1 m of each edge has a volume = 1 m3
47
![Page 48: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/48.jpg)
1 m = 10 dm
1 m3 = (10)3 dm3 = 103 dm3
Another common unit of volume is the Liter (L): which is the volume occupied by 1.0 dm3
1 L = 1 dm3 = 10-3 m3
(1dm = 10-1 m) 1 dm3 = 10-3 m3
in the same way:
1dm = 10 cm 1 dm3 = 103 cm3
cm3 = ml so 1 dm3 = 103 ml
also 1 L = 103 ml
48
![Page 49: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/49.jpg)
•TemperatureIt determine the direction of heat flow spontaneously. Heat
always flows spontaneously from a substance of higher temp. to one of lower temp.
Temp. is measured by a device called thermometer.
Three temp. scale employed in scientific studies:1) Celsius scale: (known as centigrade) (°C)
two reference temp.’s are chosen to make marking on the scale of thermometer which are the m.p.(0°C) and the b.p.(100°C) of water
difference between m.p and b.p. = 100
49
![Page 50: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/50.jpg)
2) Fahrenheit scale (°F): used in U.S.A.
m.p. of water = 32°F b.p = 212°F
difference between m.p and b.p. = 180
100°C = 180°F 1°C =(180/100)°F
1°C = (5/9)°F
So:
T(°C) = (T(°F) – 32) (5/9)
T(°F) = T(°C) x (9/5) + 32
Celsius degree is nearly twice as larger as degree in Fahrenheit scale
50
![Page 51: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/51.jpg)
3) Kelvin scale (K): it is the SI base unit for temp.
at Kelvin scale m.p. for water = 273.15K
b.p. for water = 373.15K
difference between m.p and b.p. = 100
T(K) = T(°C) + 273.15
in K-scale all temp. have positive values
Zero point in Kelvin scale (0K) is called the absolute zero 0 K = - 273.15 °C
0 K is lowest temp. that can be reached
51
![Page 52: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/52.jpg)
Fahrenheit Celsius Kelvin
- 32°F - 0°C - 273.15K
- 212°F - 100°C - 373.15 K
Melting point
of water
180°F
Boiling point of water
100°C 100 K
- - 40°F - - 40°C - 233.15 K
52
![Page 53: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/53.jpg)
53
Example: a) Convert 172.9 0F to degrees Celsius.0F = x 0C + 329
50F – 32 = x 0C9
5x (0F – 32) = 0C
95
0C = x (0F – 32)95
0C = x (172.9 – 32) = 78.3ºC95
b) Convert 172.9 0F to Kelvin
T (K) = 78.3ºC + 273 = 315.3 K
![Page 54: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/54.jpg)
Dimensional Analysis
(Using the units to solve problems)
54
![Page 55: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/55.jpg)
Dimensional analysis
Dimension: unitAnalyze: solveSo dimensional analysis is use the units to solve problems. Use the conversion factors to change the unit.Conversion factor: a ratio of equivalent measurements.Start with two things that are the same
1 cm = 10-2 m
55
![Page 56: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/56.jpg)
Dived each side to come up with two ways of writing the number 1.0
= = 1
= = 1
So : = 1 =
1 cm10-2 m
10-2 m10-2 m
10-2 m1 cm
10-2 m10-2 m
1 cm10-2 m
10-2 m1 cm
56
![Page 57: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/57.jpg)
Choose the conversion factor that get rid of the unit you do not want.
Conversion factors = 1
1 kilogram = 103 gram (equivalent statement)
= 1 =
� There are 2 conversion factors.� Multiply by the one that will give you the correct unit in your
answer.
1 kg103 g
103 g1 kg
� given quantity x conversion factor = desired quantity
desired unitgiven unit
given unit x = desired unit
57
![Page 58: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/58.jpg)
� Examples:Perform the following conversions
1. 172 mm to m.
1 mm = 10-3 m
conversion factors: or
172 mm x = 172 x 10-3 mm
1 mm10-3 m
10-3 m1 mm
10-3 m1 mm
58
![Page 59: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/59.jpg)
2. 172 cm to dm.
cm m dm
1 cm = 10-2 m 1 dm = 10-1 m
conversion factors (cm to m ): or
conversion factors (m to dm): or
172 cm x x = 172 x 10-1 dm
1 cm10-2 m
10-2 m1 cm
1 dm10-1 m
10-1 m1 dm
10-2 m1 cm
1 dm10-1 m
59
![Page 60: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/60.jpg)
3. 16.85 feet to inches1 foot = 12 inches (equivalent statements)
= 1 = (2 conversion factors)
16.85 feet x = 202.2 inch.
4. 2.85 cm to inches
2.85 cm x = 1.12 inch.
1 foot
12 inch12 inches
1 foot
12 inch.1 foot
1 inch. = 2.54 cm
1 inch.2.54 cm
60
![Page 61: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/61.jpg)
Example:A race is 1.25 miles. How long is the race in meters, and kilometers?
mile yard meter km
race in (m) = 1.25 mile x x =2011 m
race in (km) = 2011 m x =
1 m = 1.094 yd 1 mile = 1760 yd 1 km = 103 m
1 m1.o94 yd1 mile
1760 yd
1 km103 m
61
![Page 62: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/62.jpg)
Units to a Power� How many cm2 is 15 m2?
1 cm = 10-2 m
1 cm x 1 cm = 10-2 m x 10-2 m
1 cm2 = 10-4 m2
� How many m3 is 1500 cm3?
1 cm = 10-2 m
1 cm x 1 cm x 1 cm= 10-2m x 10-2 m x 10-2 m
1 cm3 = 10-6 m3
15 m2 x 1 cm2
10-4 m2= 15 x 104 cm2
1500 cm3 x 10-6 m3
1 cm3 = 1500 x 10-6 m3 1.500 x 10-3 m3=
62
![Page 63: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/63.jpg)
� how many mm3 are in 36 cm3 ?
1cm = 10-2 m 1cm3 = 10-6 m3
1 mm = 10-3 m 1 mm3 = 10-9 m3
36 cm3 x x =1 cm3
10-6 m3 1 mm3
10-9 m336 x 103 mm3
63
![Page 64: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/64.jpg)
Multiple unitsExample (1)The speed limit is 65 mi/hr. What is this in
m/s?1 mile = 1760 yds 1 meter = 1.094 yds
65 mihr
1760 yd1 mi 1.094 yd
1 m 1 hr60 min
1 min60 s
64
![Page 65: 1,the study of change](https://reader033.vdocuments.net/reader033/viewer/2022060205/55a0b9641a28abda608b477a/html5/thumbnails/65.jpg)
Example (2): A particle has a velocity of 6.51 x105 cm/h what is its velocity in mile/s.
velocity (mile/s) = 6.51x105 x x x
x x
1 m = 1.094 yd 1 mile = 1760 yd 1 cm = 10-2m
1 h = 60 min. 1 min. = 60 s
cmh
10-2 mcm 1 m
1.094 yd
1760 yd1 mile 1 h
60 min.1 min.60 s
65