Welcome to Chemistry 100!

“O Lord, how manifold are thy works! In wisdom hast thou made them all”Psalms 104:24

“Lift up your eyes on high and behold who hath created these things, that bringeth out their host by number: he calleth them all by names, by the greatness of his might, for that he is strong in power, not one faileth.”

Isaiah 40:26

Chapter 1Chemistry in our Lives

Chemistry

• Chemistry is the study of the composition, structure, reactions, and properties of matter– Often referred to as the “central science”– Builds necessary foundation for all other

branches of science

Matter

• What all materials are made of

• Has mass

• Occupies space

• Has characteristic physical and chemical properties

States of Matter

• Solid– Definite volume and shape

• Liquid– Definite volume, takes on the shape of the

container

• Gas– No definite volume or shape

Changes of State

• Very common– e.g. freezing, evaporation, sublimation

• Water– Solid ice melts to form liquid water– Liquid water evaporates to form gaseous vapor

Ice Water Water vapormelting

freezing

evaporation

condensation

Did you know? Even though icebergs float, only about 12% is visible above water.

Changes of State

A change of state is also a change of ENERGY and ORGANIZATION

Physical Properties

• Physical properties can be observed and measured without changing the identity of the substance

• Examples– Boiling point– Color– Malleability– Odor– Density

Physical Change

• A physical change in a substance occurs when there is:– A change in state– A change in the physical shape

• But NOT when there is:– A change in identity or composition

• Examples?

Chemical Properties

• Describe the ability of a substance to interact with and change into other substances

• Examples:– Reactivity with water or oxygen– Behavior with acid or base– Radioactive decay

Chemical Change

• In a chemical change (or “chemical reaction”), a new substance forms– New composition– New physical properties– New chemical properties

• Examples?

Did you know? The Statue of Liberty is one giant chemical change: copper into copper sulfate because of acid rain.

The Scientific Method

• Chemists, and all other scientists, use the Scientific Method– A set of general principles that describe a

scientist’s approach to research

• You have probably used this method, without even knowing it!– You make an observation, ask “why?”, then

find the answer

The Scientific Method

1. Observations: facts and measurement noted from nature

2. Hypothesis: a statement that explains the observation

3. Experiments: controlled procedures to test the hypothesis

4. Theory: a model that describes how the observations occur using the experimental data

• Holds true until disproved by further experiments

The Scientific Method

Scientific Method in Action

• Observation: a rosebush in my front yard has brown leaves, a drooping stem, and no flowers.

• Hypothesis: the bush needs more water

• Experiment: Rather than the usual 2L once a week, I will give the bush 3L once a week for 3 weeks.

• Observation: the rosebush is still dying!

Scientific Method in Action• Hypothesis: The bush needs more water.• Hypothesis: The bush needs less water.• Hypothesis: The bush needs a different watering schedule.• Hypothesis: The bush needs more direct sunlight.• Hypothesis: The bush needs less direct sunlight.• Hypothesis: The bush needs more fertilizer.• Hypothesis: Something in the soil is toxic to the bush.• Hypothesis: Something in the water is toxic to the bush.• Hypothesis: The temperature is too hot.• Hypothesis: The temperature is too cold.• Hypothesis: The bush is infected or infested.

The Scientific Method• Based upon OBSERVATION and REASONING

– “A few observations and much reasoning leads to error; many observations and a little reasoning leads to truth.”

— Alexis Carrell

– “Observation—activity of both eyes and ears.”— Horace Mann

– “Nothing has such power to broaden the mind as the ability to investigate systematically and truly all that comes under thy observation in life.”

— Marcus Aurelius

– 2 Ne. 4:16: “Behold, my soul delighteth in the things of the Lord; and my heart pondereth continually upon the things which I have seen and heard.”

Scientific Notation

• A system of number placement dependent on the decimal

• Every change of the decimal is a change of 10

1 0 0 0 . 0 0 4 3 5

thousandshundreds

tensones tenths

hundredthsthousandths

ten thousandthshundred thousandthsten thousands

• How would you write 0.00007 in scientific notation?

• Try writing 32,100,000 in scientific notation.

• Convert 5.65 x 10-3 from scientific notation into regular notation.

7 x 10-5

3.21 x 107

0.00565

• The estimated diameter of the known universe:

117,313,920,000,000,000,000,000 miles

(117 billion trillion miles)

• The estimated diameter of an electron:

0.00000000000124 miles

(124 trillionths of a mile)

Units of Measurement

Units of MeasurementQuantity U.S. Metric

Length 1 foot = 12 inches 1 km = 1000 m1 yard = 3 feet 1 m = 100 cm

1 mile = 5280 feet 1mm = 0.001 m

Volume 1quart = 2 pints 1 L = 1000 mL1 pint = 2 cups 1 mL = 0.001 L

1 gallon = 4 quarts 1 mL = 1 cm3

Mass 1 lb. = 16 oz. 1 kg = 1000 g1 g = 1000 mg1 mg = 0.001 g

Time 1 hour = 60 minutes 1 hour = 60 minutes1 minute = 60 seconds 1 minute = 60 seconds

1 day = 24 hours 1 day = 24 hours

Temperature Fahrenheit CelciusKelvin

Density

Quiz Yourself!• Change 9,500 into scientific notation.

• Change 2.47 x 10-4 into regular notation.

• 145 cm = ? m

• What is the volume of a 14.3g piece of lead with a density of 2.47g / mL ?

9.5 x 103

0.000247

1.45 m

5.79 mL