3.34 x 10 mm

**UNIT 1:**

**INTRODUCTION TO CHEMISTRY, MATTER, AND MATH OF CHEMISTRY**

CHEMISTRY:

the study of the composition, structure, and properties of matter and the changes it undergoes.

BRANCHES

OF CHEMISTRY

Organic

Inorganic

Physical

Analytical

Biochemistry

Theoretical

study of carbon containing compounds.

the study of compounds that do NOT contain carbon.

the study of the properties and changes of matter and their relation to energy.

the identification of the components and composition of materials.

the substances and processes occurring in living things.

the use of math and computers to understand chemical behavior and predict properties of new compounds.

Matter: anything that has

mass

and takes up space

Mass: a measure of the amount of

matter

What units do we measure mass in?

usually grams (g)

An

atom

is the smallest unit of an element that maintains the properties of that element.

An

element

is a pure substance made of only one kind of atom.

A

compound

is a substance that is made from the atoms of two or more elements that are chemically bonded.

Elements are found on the Periodic Table!

Periodic Table Tile

Extensive Properties:

Depend on the amount of matter that is present.

Intensive Properties:

Depend on the type of matter present.

ex: volume & mass

ex: melting point, boiling point, & density

Physical Property

Chemical Property

a characteristic that can be observed or measured without changing the identity of the substance.

a substance's ability to undergo changes that transform into different substances.

1. color

2. burn

ID as physical or chemical properties

3. conductivity

4. rust

P

C

P

C

Physical Change

the composition of the matter does NOT change!!!

Chemical Change

substances are converted into different substances.

1. cutting grass

2. burning wood

3. breaking glass

4. food digesting

5. boiling water

6. ice melting

P

C

P

C

P

P

Law of Conservation of Mass

"Mass cannot be created nor destroyed during a chemical reaction."

Mixture

You've already learned what an element and a compound is.. so whats a..

A blend of two or more kinds of matter, each which retains its own identity and properties.

ANSWER WITH YOUR FEET

1. Salt

2. Block of Iron

3. Glass of Cola

4. Mercury in a Thermometer

5. Ice

6. Vinegar and Oil

7. Copper Wire

8. Earth's Atmosphere, when dusty

9. Earth's Atmosphere, when dust free

10. Rust

11. Brass

12. Aluminum Foil

13. Homogenized Milk

14. Sugar

15. Sugar Water

16. Sandy Water

18. Blood

17. Neon Gas in a Neon Sign

Using the models in front of you, diagram each of the following:

element

compound

heterogeneous mixture

homogeneous mixture

SI Units of Measurement

volume

density

the amount of space occupied by an object

units: mL or cm

3

the ratio of mass to volume

units: g/mL

density = -----------

mass

volume

A sample of aluminum metal has a mass of 8.4 g. The volume of the sample is 3.1 mL. Calculate the density.

Answer

2.7 g/mL

DO NOT FORGET YOUR UNITS

example problem:

Accuracy

Precision

how close a measurement is to the accepted value

how close the measurements are to each other

ERROR IN MEASUREMENT

always estimate a measured value to one questionable digit!!

Scientific Notation Review

M x 10

n

M = a number greater than or equal to 1 but less than 10

n = a whole number

0.00012 mm = 1.2 x 10 mm

-4

65000 km = 6.5 x 10 km

4

negative exponents move the decimal back to the left

positive exponents move the decimal back to the right.

PRACTICE

Write the following numbers in scientific notation.

1.) 560000 g

2.) 33400 mm

3.) 0.0004120 m

5.6 x 10 g

5

4

-4

Significant Figures

all the digits known with certainty plus one final digit in a measurement.

P

A

Rules for Significant Figures!

If a decimal is present start from the Pacific side. (left)

If a decimal is absent start from the Atlantic side. (right)

Count the first nonzero digit you encounter and ALL digits after that!

5

6

4

3

4

3

5

1

1

6

5

6

Critical Thinking Question

Suppose the value "seven thousand centimeters" is reported to you. How should the number be expressed if it is intended to contain the following?

1 significant figure

4 significant figures

6 significant figures

7000 cm

7000. cm

7000.00 cm

Why must we use significant figures in calculating answers?

Because the answers given on a calculator can be derived results with more digits than are justified by the measurements.

RULES

When adding or subtracting decimals, the answer must have the same number of digits to the right of the decimal point as there are in the measurement with the fewest digits to the right of the decimal.

FOR ADDING AND SUBTRACTING

25.1 g

+ 2.03 g

27.13 g

27.1 g

FOR MULTIPLYING AND DIVIDING

RULES

The answer can have no more significant figures than are in the measurement with the fewest number of significant figures

density =

mass

volume

=

3.05 g

8.47 mL

= 0.360094451

g

mL

=0.360

g

mL

169.0

582.8

2026.8

90.

11

0.81

417

2.8 x 10

3

28.6

61.25

11.000

159

What about units?

Adding with units

Subtracting with units

Multiplying with units

Dividing with units

5 g + 2 g =

7 g

6 g - 3 g =

3 g

4 m X 3 m =

12 m

2

16 m

2

_________

4 m

= 4 m

2 m X 2 m X 2 m =

8 m

3

The Mole

mol: the amount of substance that contains as many particles as there are atoms in exactly 12 g of carbon-12

the "mol" is a counting unit just like "dozen"

Avogadro's Number

6.02 x 10

23

the number of particles in exactly one mole of a pure substance

MISSING POSTER

You are to create a missing poster for a lost measurement.

The poster must include:

Any number less than 1 OR greater than 10, with units! (ex: 0.0670 mm or 13,500 ft)

A paragraph describing the measurements last known whereabouts and what to do if the measurement in found.

The number written in scientific notation.

How many significant figures are in the number.

You must use color and be creative!

If you spread Avogadro's number of unpopped popcorn kernels across the USA, the entire country would be covered in popcorn to a depth of over 9 miles.

MOLAR MASS

The mass of one mole of a substance

units: g/mol

He 4.00 g/mol

Li 6.94 g/mol

H O 17.99 g/mol

2

The molar mass of an element is numerically equal to the atomic mass of the element in atomic mass units.

Conversion Factors

a ratio derived from the equality between two different units that can be used to convert between units.

4 quarters = 1 dollar

4 quarters

4 quarters

1 dollar

1 dollar

Lets use the "bridge" method to determine how many

quarters are in 12 dollars...

12 dollars

4 quarters

1 dollar

= 48 quarters

Use the bridge method to complete the following metric conversions:

1.) 10.5 g = ____ kg

Remember these prefixes?

2.) 1.2 L = ____ mL

3.) 1.57 km = ____ m

10.5 g

1000 g

1 kg

= 0.0105 kg

1.2 L

1 L

1000 mL

1.57 km

1 km

1000 m

Don't count significant figures in the conversion factor.

= 1200 mL

= 1570 m

mole-mass conversions

# grams A = 1 mol A

1 mol A

# grams A

1 mol A

# grams A

"A" has to be the same substance. You cannot use this conversion factor to convert between different substances.

How many grams of Helium are there in 2.00 moles of Helium?

ex:

2 mol He

1 mol He

4.00 g He

= 8.00

g He

SET UP BRIDGES ON YOUR WHITEBOARDS FOR THE FOLLOWING PROBLEMS:

1. What is the mass in grams of 3.50 mol of the element copper, Cu?

2. How many moles of calcium, Ca, are in 5.00 g of calcium?

3.50 mol Cu

1 mol Cu

63.55 g Cu

= 222 g Cu

5.00 g Ca

40.08 g Ca

1 mol Ca

= 0.125 mol Ca

Avogadro's Number Conversions

(or particles)

1 mol A

1 mol A

6.02 X 10 atoms A

(or particles)

(or particles)

23

6.02 X 10 atoms A

23

6.02 X 10 atoms A = 1 mol A

23

Use Avogadro's number to convert between moles and atoms/particles.

Ex:

1. How many moles of lead, Pb, are in 1.50 X 10 atoms of lead?

12

2. How many moles of tin, Sn, are in 2500 atoms of tin?

1.5 X 10 atoms Pb

12

6.02 X 10 atoms Pb

23

1 mol Pb

= 2.49 X 10 mol

-12

2500 atoms Sn

6.02 X 10 atoms Sn

23

1 mol Sn

= 4.2 X 10 mol

-21

TEXTBOOK PROBLEMS:

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PAGE 303 # 26&27