Basic Concepts:Basic Concepts:Matter and MeasurementMatter and Measurement

Introduction:The scientific method

Macro and Particulate Concepts

Goals:

1. Classify matter.2. Recognize elements, atoms, compounds, and

molecules.3. Identify physical and chemical properties and

changes.4. Apply the kinetic-molecular theory to the properties

of matter.5. Use metric units and significant figures correctly.6. Understand and use the math’s of chemistry.

The scientific methodThe scientific method• InquiryInquiry – pose a reasonable QUESTION: ?

– Look for what others have done.

• Form a __________________________ – tentative explanation or prediction of experimental observations.– Perform experiments.– Summarize observations in the form of a general rule.

• If the hypothesis is always true it may become a _______ – concise verbal or mathematical statement of a relation that seems always to be the same under the same conditions.

• If the human mind conceives a __________ – a unifying principle - to explain the observations.

Always changing!!!

Chemist’s views of matterChemist’s views of matter

What is matter?What is matter?What are the states of matter?What are the states of matter?

• Matter is __________________________.

There are other two states of matter. Do you know what are they?

SOLID: rigid shape, fixed volume

LIQUID: no shape of its own, fixed volume

GAS: no fixed volume, it is determined by the size of the container

What is the kinetic-molecular What is the kinetic-molecular theory?theory?

• The theory which describes matter as extremely tiny particles (atoms and molecules) in constant motion.

• Also, the higher the temperature the ________ the particles move. The kinetic energy (energy of motion) acts to overcome the forces of _________ between the particles.

What are physical What are physical properties?properties?

• Physical properties:Physical properties: properties which can be observed and measured without changing the identity composition of a substance.Examples: Color, state of matter, melting point, boiling point, density, hardness, odor.

• Physical changes:Physical changes: - boiling of a liquid- melting of a solid- dissolving a solid into a liquidto give a homogeneous mixture(a solution).

• Density: important and useful physical property.– ratio of the mass of an object to its volume.

Which one has moremass per unit volume?

Which one would be heavier on Earth?

DensityDensity

21.5 g/cm21.5 g/cm33

Aluminum

2.7 g/cm2.7 g/cm33

Platinum

Density =mass

volume

DensityDensity• Density is an INTENSIVE property of

matter – does NOT depend on quantity of matter.

• EXTENSIVE properties – depend on the quantity of matter analyzed.

Students should become familiar with

using density in calculations.

Temperature MassMelting Point LengthColor VolumeHardness

Mercury (Hg) has a density of 13.6 g/cmMercury (Hg) has a density of 13.6 g/cm33. . What is the mass of 95 mL of Hg in grams? What is the mass of 95 mL of Hg in grams?

In kilograms?In kilograms?

Solve the problem usingSolve the problem using

DIMENSIONAL ANALYSISDIMENSIONAL ANALYSIS-carrying on UNITS--carrying on UNITS-

*Calculations need to be done in same units.

1 cm3 = 1mL

1. Calculate mass:

2. Calculate mass in Kg:

Mercury (Hg) has a density of 13.6 g/cm3. What is Mercury (Hg) has a density of 13.6 g/cm3. What is the the massmass of 95 mL of Hg in grams? In kilograms? of 95 mL of Hg in grams? In kilograms?

Density =mass

volume

What are chemical properties?What are chemical properties?• Chemical properties:Chemical properties: those which describe the way

a substance may change, or react, to form other substances. Example: Flammability

• Chemical change or Chemical reaction:Chemical change or Chemical reaction:transformationof one or moreatoms ormoleculesinto one or moredifferentmolecules.

Chemical vs. Physical Chemical vs. Physical PropertiesProperties

ExplosivenessCorrosivenessFlammabilityToxicityTemperatureMassVolumeColorDensity

How do we classify matter?How do we classify matter?

Ask: Do the substance has an even texture (to the microscopic level)?YES – homogeneousNO - heterogeneous

How can we separate How can we separate mixtures?mixtures?

• Filtration

• Distillation• Chromatography

What is an element?What is an element?Element: substance composed of ____________ ______________. Pure substance that cannot be decomposed by ordinary means to other substances.

Students should become familiar with the

periodic table - symbols and names of the elements.

Aluminum

Bromine

The Periodic TableThe Periodic TableDmitri Mendeleev (1834 - 1907)Dmitri Mendeleev (1834 - 1907)

Try to answer: Why are elements organized in such a way?

What is an atom?What is an atom?

• An atom is ___________________ _______that retains the chemical properties of that element.

Copper atomsCopper atomson silica surface.on silica surface.

Distance across = 1.8 nanometer (1.8 x 10-9 m)

What are atoms composed What are atoms composed of?of?

An atom consists of

• a nucleus– of _________ and __________

• and _____________ in space around the nucleus.

Electron cloud

Nucleus

What is a compound?What is a compound?

• Compounds: substance composed of two or more different ________; it can be decomposed into those __________.– Have distinctly different properties from their

parent elements.– Have a definite percentage composition (my

mass) of their combining atoms.– Might be composed of ions (electrically charged

atoms, or group of atoms) or molecules (the smallest discrete units that retain the chemical characteristics of the compound).

– Can be represented by their formula.

A compound:A compound:

The red compound is composed of• nickel (Ni) (silver)• carbon (C) (black)• hydrogen (H) (white) • oxygen (O) (red)• nitrogen (N) (blue)

The red compound is composed of• nickel (Ni) (silver)• carbon (C) (black)• hydrogen (H) (white) • oxygen (O) (red)• nitrogen (N) (blue)

What is a molecule?What is a molecule?

• A molecule is the ___________ ________that retains the chemical characteristics of the ____________.

• Composition of molecules are given by a MOLECULAR FORMULA.

HH22OOCC88HH1010NN44OO22 - caffeine - caffeine

Label: Elements vs. Label: Elements vs. CompoundsCompounds

What are SI base units?What are SI base units?

• SI – International System of UnitsInternational System of Units. It is based on the metric systemmetric system.

• Give the units with their symbol for:Mass kilogram (kg)Length ___________Time ___________

Temperature ___________

Learn Table 1.2 in your textbook (page 26).

LengthLength

1 m = 100 cm = 1000 mm

1 mm = 1x 10-3 m

1 nm = 1 x 10-9 m O—H distance O—H distance ==9.58 x 109.58 x 10-11 -11 mm9.58 x 109.58 x 10-9 -9 cmcm0.0958 nm0.0958 nm

O—H distance O—H distance ==9.58 x 109.58 x 10-11 -11 mm9.58 x 109.58 x 10-9 -9 cmcm0.0958 nm0.0958 nm

Students should become familiar with:1. equivalents of units and their

conversions.

2. exponential notation and prefixes.

Unit ConversionUnit Conversion

0.0958 nm to m

Look for conversion factor(s):

Temperature ScalesTemperature Scales

Notice that 1 kelvin = 1 degree Celsius1 kelvin = 1 degree Celsius

Boiling point Boiling point of waterof water

Freezing point Freezing point of waterof water

CelsiusCelsius

100 ˚C100 ˚C

0 ˚C0 ˚C

100˚C100˚C

KelvinKelvin

373 K373 K

273 K273 K

100 K100 K

FahrenheitFahrenheit

32 ˚F32 ˚F

212 ˚F212 ˚F

180˚F180˚F

Students should learn the rules for significant figures!

Temperature ScalesTemperature Scales

100 oF38 oC311 K

oF oC K

T(oC) = 5oC

9oF [T(oF) – 32]

T(K) = 1 K

1oC [T(oC) + 273.15 oC]

RememberRemember

• Go over all the contents of your textbook.

• Practice with examples and with problems at the end of the chapter.

• Practice with OWL tutor.• Practice with the quiz on CD of

Chemistry Now.• Work on your assignment for Chapter

1.