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Matter and Energy

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1.1 Matter and Its Classification: anything that occupies space & has mass

• Forms of energy are NOT matter. • Heat & light do not occupy space & have no mass.

We classify matter to better understand• Pure substances• Mixtures

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Matter – anything that occupies space and has

mass

Pure Substances – have uniform chemical

composition throughout and from sample to

sample

Mixtures – are composed of two or

more pure substances and may or may not have

uniform composition


1.1 Matter and Its Classification: same

composition throughout, & from sample to sample.

• can be further classified as either elements or compounds.

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Pure Substances

Elements Compounds

: a substance that cannot be broken down into simpler substances even by chemical reaction• Are separated further into metals, nonmetals & metalloids

: a substance composed of 2 or more elements combined in definite proportions

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1.1 Matter and Its Classification

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PureSubstances

Elements

Metals Nonmetals

Compounds


: Classification of Matter

• Identify the metals. • Explain the characteristics you considered in making your

decision.

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Figure 1.4

Sulfur TinAluminumCarbonGold

Phosphorus Copper Bromine Nickel Lead


1.1 Matter and Its Classification: an element having the following properties:

• Lustrious• Malleable and ductile• Conductor of heat and electricity• Usually a solid at room temperature (except mercury)

: an element having the following properties:• Dull• Brittle• Insulator of heat and electricity• May be a solid, liquid or gas at room temperature

: an element having properties of both metals and nonmetals

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1.1 Matter and Its Classification: the smallest unit of an element that retains the

chemical properties of that element.• Matter is composed of atoms.

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1.1 Matter and Its Classificationa pure substance composed of 2

or more elements (atoms) combined chemically in definite proportions. • A compound has properties that are different from those of its

component elements.• A compound can be separated into their elements by chemical

means

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1.1 Matter and Its ClassificationWater, H2O, is a compound that can be broken down by

electrolysis (a chemical process) to its elements H2 and O2.

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H2 O2

H2O

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1.1 Matter and Its ClassificationPure sand is the compound silicon dioxide, SiO2.• What does the formula tell us about the combination of

elements in this compound?

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Activity: Elements and CompoundsIdentify each of the following as an element or compound.

1. He2. H2O3. sodium chloride4. copper

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Matter – anything that occupies space and has mass

Pure Substances – have uniform (the same) chemical composition

throughout and from sample to sample

Elements

Metals

Metalloids

Nonmetals

Compounds

Mixtures – are composed of two or more pure substances, either

elements or compounds.

Homogeneous Heterogeneous

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1.1 Matter and Its Classification: two or more elements or compounds .

• Mixtures can be separated by physical processes.

• Example: salt & water

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Salt water can be separated into salt and water by the process of evaporation, which is a physical

process.


Mixtures can be further classified as homogeneous and heterogeneous.

: the same composition throughout.

: do not have uniform composition throughout.

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: Classify each of the following mixtures as homogeneous or heterogeneous:1. Salt water2. Lake water3. Tap water4. Air5. Brass (an alloy of Cu and Zn)6. Potting soil7. Cake mix

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Figure 1.7


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Representations of Matter• Macroscopic – we can see with our eyes• Molecular level – a theoretical magnification to a level that

shows atoms• Symbolic – shorthand using element symbols

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He


Representations of Matter

: • Does this image represent atoms or

molecules?

• Is this an element, compound, or mixture?


: Classification

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Classify each of the following as an element, compound or mixture:

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: a characteristic that we can observe. : is a process that changes the properties of a

substance.

: a characteristic that we can observe without changing the composition of a substance.

– Color– Odor– Mass– Density

: a process in which no new substances are produced.

– Change in physical state

1.2 Physical & Chemical Changes & Properties of Matter

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qualitative properties

quantitative properties


: A characteristic that can only be observed when a substance is converted into one or more other substances

– Pennies will tarnish– Gasoline is flammable

: a process where one or more substances are converted into one or more new substances (chemical reaction)

– Pennies tarnishing– Burning gasoline– Evidence of a chemical change:

bubbling a permanent color changea sudden change in temperature

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1.2 Physical & Chemical Changes & Properties of Matter

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Is Boiling Water a Chemical or Physical Change?

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: Physical & Chemical Changes

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Do the following images represent a chemical or physical change?


: Physical & Chemical Changes

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Do the following images represent a chemical or physical change?

Classify each of the following as a physical or chemical change:

1. Evaporation of water

2. Burning of natural gas

3. Melting a metal

4. Converting H2 and O2 to H2O

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More Physical Properties: Mass: measures the quantity of matter

• common units are grams (g)• Prefixes make it easier to refer to large or small masses

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Prefixes Mass measurementsgiga- G 109 1 Gg = 109 gmega- M 106 1 Mg = 106 g

nano- n 10−9 1 ng = 10−9 g pico- p 10−12 1 pg = 10−12 g


More Physical Properties: Volume: amount of space a substance occupies

• Volume of a solid can be calculated by measuring the sides of a cube or rectangular side, then multiplying them

Volume = length × width × height

• Common units are centimeters cubed (cm3), sometimes called cubic centimeters.

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More Physical Properties: Volume• Volumes of liquids are usually measured in units of

milliliters (mL).

• 1 mL = 1 cm3 exactly

• How many mL in 1 L?

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: Volume Unit Conversions• Convert 25.0 mL to L.

• Convert 25.0 mL to quarts (1 L = 1.057 qt)

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More Physical Properties: Density

: the ratio of the mass to its volume 𝐷 = $%&&

'()*$+• ,

$-or ,.$/for (s) & (l)

• ,- for (g)

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Figure 1.19


More Physical Properties: DensityThe density of a substance is the ratio of its mass to volume:

𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑚𝑎𝑠𝑠𝑣𝑜𝑙𝑢𝑚𝑒

: If the mass of the cube is 11.2 grams, what is its density?

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2.0 centimeters

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: Density

Compare the density of the Dead Sea water and of the person. – Which has the higher density?

– How can you tell?

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The cube of gold has a greater mass than that of aluminum. Which cube has the greater density?

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: Density


Given that these samples of metals have the same mass, which has the greater density?

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Gold Aluminum

: Density

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• Which is more dense, regular soda or diet soda?

• How can you tell?

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: Density


What is less dense, liquid water or ice?

How can you tell?

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: Density


: a measure of how hot or cold something is relative to some standard • is measured with a thermometer• Scientific units are degrees Celsius, °C & kelvins, K

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More Physical Properties: Temperature

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1.3 Energy and Energy Changes: the capacity to do work or to transfer heat

• Two main forms of energy are:: the energy of motion

: energy possessed by an object because of its position• Other energies are forms of kinetic and potential energy

(chemical, mechanical, electrical, heat, etc.)• When chemical or physical changes occur, energy changes

also occur.• Some processes release energy (exothermic) and some

require an energy input (endothermic)

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When hydrogen burns with oxygen, energy in the form of heat and light

is released.

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This process is

1.3 Energy and Energy Changes


Electricity is used to decompose water into its elements.

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This process is

1.3 Energy and Energy Changes

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Kinetic and Potential Energy

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Figure 1.29


Which pair of molecules has more kinetic energy?

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Figure from p. 52

: Kinetic Energy


1.4 Scientific Inquiry: an approach to asking questions and

seeking answers that employs a variety of tools, techniques, and strategies• The method generally includes:

- observations - hypotheses- laws - theories

• Observations include: - experimentation - collection of data

• A hypothesis is a tentative explanation for the properties or behavior of matter that accounts for a set of observations and can be tested.

: predict outcomes under certain circumstance.- Often equations

: explain why observations, hypotheses, or laws apply under many different circumstances.

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Math Toolbox 1.1 - Scientific NotationA number written in scientific notation is expressed as: C × 10n

where:- C is the coefficient, ≥ 1 and <10, - n is the exponent, a ± integer

• C is obtained by moving the decimal point to immediate right of the leftmost nonzero digit in the number

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3245 Left 3.245 × 103

0.000003245 Right 3.245 × 10−6

3,245,000,000 Left 3.245 × 109

0.0050607 Right 5.0607 × 10−3

88 Left 8.8 × 101

2.45 Neither 2.45 × 100

• n is equal to the number of places moved to obtain C- If the decimal point is

moved to the left, then n is positive.

- If the decimal point is moved to the right, then n is negative.


: Scientific Notation

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9,000,000,655.00

0.00000834

1.21

14.82

299,800,000

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Convert the values shown in decimal form to scientific notation.


You can simplify calculations with exponents:

• Multiplication – add exponents(4.0 × 106)(1.5 × 10−3) = (4.0 × 1.5) × 106+(−3) = 6.0 × 103

• Division – subtract exponents(4.0 × 10−2)/(2.0 × 103) = (4.0/2.0) × 10(−2)−3 = 2.0 × 10−5

• Raising the exponent to a power –multiply exponents(3.0 × 104)2 = (3.0)2 × 104×2 = 9.0 × 108

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Math Toolbox 1.1 - Scientific Notation

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: Scientific NotationMultiplication and Division of Exponents

1) (6.78 × 103)(5.55 × 10−4) =

2) (2.99 × 10−9) / (4.03 × 10−6) =

3) (7 × 103)4 =

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: the numbers in a calculation that represent the uncertainty of the measurements used in the calculation.• All non-zero digits are significant.

435 g – 3 SF’s

• Zeroes: zeroes are

405 g – 3 SF’s40.5 g – 3 SF’s

zeroes are there is a decimal5.00 g – 3 SF’s500 g – 1 SF

zeroes are NEVER significant 0.151 g – 3 SF’s0.00405 g – 3 SF’s

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Math Toolbox 1.2 – Significant Figures


: Significant Figures

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2619628.000.0034169 × 1019

1.2407661 × 10−2

Determine the number of significant figures in each of the following values.

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• Your final answer must reflect the number of SF’s in the least accurate (most uncertain) measurement.

• The least accurate measurement is determined differently depending on the mathematical operation you are performing.

• Count SF’s in each value• Use the LEAST number of SF’s for the final answer

234.506 cm x 4455.9 cm x 0.12 cm = 1.2 ⋮ 54× 105

= 1.3 × 105 cm3

: Perform the following calculation and express the final answer to the correct number of significant figures:4.301 x 0.079010 =

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• Determine the uncertainty of each value in the calculation• Use the largest uncertainty for the final answer

234.506 cm0.12 cm

+ 4455.9 cm4690. ⋮ cm

: Perform the following calculations and express the final answer to the correct number of significant figures:1. 435.1 + 790.1 =2. 0.908 – 0.899 =

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0.001 cm0.01 cm0.1 cm0.1 cm


• The appropriate rules must be applied at each step of the calculation.

=>.@AB=>.@==>.@C

= @.@C⋮@@=>.@C

= 0.001⋮ 87 = 0.002

: Perform the following calculations and express the final answer to the correct number of significant figures:

1. [email protected]@.A@[email protected]

=

2. K.@I.>J

+ >.ANI=.@K

=

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: Significant FiguresCalculate the following to the correct number of significant figures:1. 14.6608 +12.2 + 1.500000𝑥10> =

2.J .JT K@UV I TK@WX

C .CJ TK@YZ=

3. IJ .CMLJJ .=>A>.K=CJ

=

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:1. Decide what the problem is asking for.2. Decide what the relationships is between the information

given and the desired quantity.3. Set up the problem logically, using the relationships decided

upon in step 2.

4. Check the answer to make sure it makes sense, both in magnitude and units.

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Math Toolbox 1.3–Dimensional Analysis


: Dimensional Analysis1. How many inches are in 2 kilometers?

2. What is the volume in cubic centimeters of a 14 lb block of gold?

3. Dan regularly runs a 5-minute mile. How fast is Dan running in feet per second?

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matter and energy - orange coast collegeocconline.occ.cccd.edu/online/avieau/chp1notesthree.pdf ·...

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