Unit 0 - Chapter 1 notes - B and L.ppt

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UNIT 0:

Chapter 1

: Introduction

to Matter and Change

•

Scientific Method

•

Physical vs. Chem Changes

•

Units, Measurements and Sig Figs

•

Matter and Nomenclature

(2)

Scientific Method



A systematic/organized way for scientists

to solve a problem or answer a question.



There are about 5 steps to the scientific

method



What are they?

(3)

Sci Method

(4)

Variables:



Independent Variable

– something that

is changed by the scientist



Dependent Variable

– something that

might be affected by the change in the

independent variable



Controlled Variable

– a variable that is

not changed

(5)

Claim – Evidence - Reasoning



Claim

– a statement that answers a question



Evidence

– observations, data tables,

graphs, pictures that support the claim



Reasoning

– scientific principles, readings,

(6)

(7)

Chemical vs. Physical Properties

Physical:

Can be

measured without

change

MP

BP

Color

Texture

Density…

Chemical:

How a

substance reacts to

form others (new)

Changes used to ID:

1.

Bubbles

2.

Ppt

3.

Light

4.

Heat

5.

(8)

Properties of Matter Classified as:

Extensive properties

Intensive properties

Volume Mass

Energy Content (think Calories!)

depend on the amount

of matter that is present.

do not depend on the

amount of matter present (think physical

prop)

Melting point

(9)

Separation of a Mixture: 3

main

ways to separate

1.

Filtration

2.

Distillation

3.

Chromatography



How would you separate iron fillings from

sand?

(

hint

: it is not one of the common 3

methods of separation listed above)

(10)

The constituents of the mixture retain their

The constituents of the mixture retain their

identity and may be separated by physical

means.

Answer:

(11)

Separation of a Mixture

(12)

(13)

(14)

Separation of a Compound

The Electrolysis of water

Water  Hydrogen + Oxygen

H₂O  H₂ + O₂

Reactant  Products

Compounds must be

separated by chemical

means.

With the application of electricity, water can be separated into its elements

(15)

Phase

Differences

Solid

Solid – definite volume and shape; particles packed in fixed positions.

Liquid

Liquid – definite volume but indefinite shape;

particles close together but not in fixed positions

Gas

Gas – neither definite volume nor definite shape; particles are at great distances from one another

Plasma – high temperature, ionized phase of matter as found on the sun. (not really emphasized in

(16)

The Fundamental SI Units

The Fundamental SI Units (le Système International, SI)(le Système International, SI)

Physical Quantity

Name

Abbreviation

Mass

kilogram

kg

Length

meter

m

Time

second

s

(17)

SI Prefixes Common to Chemistry

Prefix

Unit Abbr. Exponent

Mega

M

10

6

Kilo

k

10

3

Deci

d

10

-1

Centi

c

10

-2

Milli

m

10

-3

Micro



10

-6

Nano

n

10

-9

(18)

Measurements



Use the correct instrument to make your

measurement



A digit that must be

estimated

is called

uncertain

. A

measurement

always has some

degree of uncertainty.



Measurements are performed with

instruments



No instrument can read to an infinite

(19)

Uses for laboratory Glassware

(20)

Volume:

(21)

Precision and Accuracy

Accuracy

Accuracy refers to the agreement of a particular refers to the agreement of a particular value with the

value with the truetrue value.value. Precision

Precision refers to the degree of agreement among refers to the degree of agreement among several measurements made in the same manner.

several measurements made in the same manner.

Neither accurate nor

precise

Precise but not

(22)

To measure accuracy



% error can be used

% error = experimental results - accepted value

(23)

Rules for Counting Significant Figures

- Details

1.

Nonzero integers

always count as

significant figures.

3456

4

(24)

Rules for Counting Significant Figures

- Details

2.

Zeros

Leading zeros

do not count as

significant figures.

significant figures.

0.0486

3

(25)

Rules for Counting Significant Figures

- Details

3.

Zeros

Captive

zeros

always count as

significant figures.

significant figures.

16.07

4

(26)

Rules for Counting Significant Figures

- Details

4. Zeros

Trailing zeros

are significant

only

if the

number contains a decimal point.

9.300

4

(27)

Sig Fig Practice #1

How many significant figures in each of the following?

1.0070 m



5 sig figs

17.10 kg



4 sig figs

100,890 L



5 sig figs

3.29 x 10

3

s



3 sig figs

0.0054 cm



2 sig figs

3,200,000 m/s



2 sig figs

(28)

Rules for Significant Figures in

Mathematical Operations



Multiplication and Division

:

# sig

figs in the result equals the number in

the least precise measurement used in

the calculation.

6.38 x 2.0 =

12.76

(29)

Sig Fig Practice #2

3.24 m x 7.0 m

Calculation

Calculator says:

Answer

22.68 m

2

23 m

2

100.0 g ÷ 23.7 cm

3

4.219409283 g/cm

3

4.22 g/cm

3

0.02 cm x 2.371 cm

0.04742 cm

2

0.05 cm

2

710 m ÷ 3.0 s

236.6666667 m/s

240 m/s

(30)

Rules for Significant Figures in

Mathematical Operations



Addition and Subtraction

: The

number of decimal places in the result

equals the number of decimal places in

the least precise measurement.

6.8 + 11.934 =

18.734

(31)

Sig Fig Practice #3

3.24 m + 7.0 m

Calculation

Calculator says:

Answer

10.24 m

10.2 m

100.0 g - 23.73 g

76.27 g

76.3 g

0.02 cm + 2.371 cm

2.391 cm

2.39 cm

713.1 L - 3.872 L

709.228 L

709.2 L

1818.2 lb + 3.37 lb

1821.57 lb

1821.6 lb

(32)

Dimensional Analysis



Use conversion factors to change the units



Conversion factors = 1



1 foot = 12 inches (equivalence statement)



12 in

=

1₁

= =

1 ft.

12 in



2 conversion factors



multiply by the one that will give you the correct

units

in your answer.

(33)

Convert 223 mL to L

223 mL 1 L

1000 mL

(34)

Dimensional Analysis Method of Solving Problems

Conversion Unit 1 L = 1000 mL

1L

1000 mL

1.63 L x _{= 1630 mL}

1L

1000 mL

1.63 L x _{= 0.001630 L}2

mL

(35)

The speed of sound in air is about 343 m/s. What is this speed in miles per hour?

1 mi = 1609 m 1 min = 60 s 1 hour = 60 min

343 ms x _{1609 m}1 mi x_{1 min} 60 s 60 min 1 hour

x _{= 767 mi}

hour meters to miles

seconds to hours

(36)

Density: D=m/V

 Ratio of mass to volumeRatio of mass to volume

 Useful for identifying a Useful for identifying a compound

compound

 Useful for predicting Useful for predicting weight

weight

 An intrinsic propertyAn intrinsic property

(37)

Density

– SI derived unit for density is kg/m

3

1 g/cm

3

= 1 g/mL = 1000 kg/m

3

density = mass

volume

d =

V

m

A piece of platinum metal with a density of 21.5

g/cm

3

has a volume of 4.49 cm

3

. What is its

mass?

d =

V

m

21.5 g

cm

3

(38)

What about percentages? How can they be

used to measure amount?

Ex. A 2.0 gram, 14 K gold ring contains 58.3% gold by mass. How many grams of pure gold does the ring contain?

58.3 100

x 2.0

x _{= 1.2 g gold}

•

Percent by mass is a common way to express

quantity.

(39)