CHE-108Chemistry Lab

Instructor: Robert Goldman

Today in lab…

Experiment #1 – Introduction & Physical Properties

Experiment and lab exercises done in class

Homework #1 completed and turned in next week – DUE AT START OF CLASS

Experiment #1

Chemistry: the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions

Experiment #1

What is matter?

Anything that has mass and occupies space

The atom is the smallest indivisible unit of matter!

Experiment #1

What is mass?

The amount of matter present in a sample.

MASS IS CONSTANT!!

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Mass vs. Weight?Technical definition of weight:“the vertical force exerted by a mass as a result of

gravity”

Weight is NOT constant Defined by relationship of mass and gravity.

– Ex: you WEIGH less on the moon (less gravity) but your MASS is the same.

Experiment #1

What is a chemical property?

Property that changes in a reaction

Ex: Rust formation on iron due to oxidation, ability of wood to burn.

You can’t “un-rust” metal or “un-burn” wood!

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What is a physical property?A property that can be observed without changing the

chemical composition of the sample.

Ex: Color, shape, mass, volume, ability to dissolve: You CAN “un-dissolve” salt!

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You can use a samples chemical and physical properties to separate different components of a solution.

For example, a mixture of sand and sugar can be separated in water:

Sand sinks to bottom, sugar dissolves.Pour off water, evaporate water, sugar is left.

Experiment #1

What is density?

“Mass per unit volume”

Ex: the density of H20 is 1g/mL

So… 10mL of H20 is how many g?

Experiment #1

Relationship of Mass, Volume, and Density

Density=Mass/Volume (D=M/V)

If the density of H20 is 1g/mL and the volume is 10mL…

1g/mL=M/10mL

We can solve for M and arrive at 10g!

Experiment #1

Rearranging the density equation:

D=M / V

M=D x V

V=M / D

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In science, we use the METRIC SYSTEM

Temperature: ºC vs. ºF

Volume: liters vs. gallons

Length: meters vs. yards

Mass: grams vs. ounces

Always include these units in calculations!

Experiment #1

It is important to be able to convert between english and metric units.

The boiling point for water is 212 ºF, what is the B.P. in ºC?

Experiment #1

Temperature conversions

212 ºF to ºC

ºC=(5/9) º F-32ºC=(5/9) 212 ºF-32ºC=(5/9) (180)ºC=100 ºC

Experiment #1

Temperature conversions

Water freezes at 0 ºC, how about in ºF?

ºF=(9/5) ºC + 32

ºF=[(9/5) 0ºC] +32

ºF=(0) + 32

ºF=32 º freezing temperature

Experiment #1

10mm in 1cm

100cm in 1m

1000m in 1km

100ųL in 1mL

1000mL in 1L

100ųg in 1g

1000g in 1kg

Interconverting Metric Units

Experiment #1

What is energy?

Technically: the capacity for doing work.

Forms: thermal, mechanical, electrical, and chemical.

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LAW OF CONSERVATION OF ENERGY

AKA First Law of Thermodynamics

ENERGY IS NEVER CREATED OR DESTROYED! It may, however, be transformed from one form into

another. The amount of energy in the universe is constant.

Experiment #1

LAW OF CONSERVATION OF MASS/MATTER

AKA -Lavoisier Law

Mass can be neither created nor destroyed during a chemical reaction- only changed from

one form to another.

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Scientific Notation

… a method for “compacting” very large or small numbers.

Ex: 1.3 x 106 or 3.2 x 10-2

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Scientific Notation

1.3x106

Move the decimal point to the RIGHT (+) six places…

1,300,000Or… take out the decimal and add 5 0’s after the

number

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Scientific Notation

3.2x10-2

Move the decimal point to the LEFT (-) two places…0.032

Or… take out the decimal and add one 0 before the number

(The zero before the decimal isn’t ESSENTIAL, but it is helpful…)

Experiment #1

For today’s lab… Follow directions outlined in lab manual. Record results on worksheets- NOT IN BOOK. ASK QUESTIONS!