Chemistry Intro

Section 1-1

What is chemistry? The study of the composition, structure, and

properties of matter and the changes it undergoes.

Branches of Chemistry

Organic chemistry – study of carbon-containing compounds

Inorganic chemistry – study of all substances not classified as organic (those substances that don’t contain carbon)

Physical chemistry – study of matter and energy

Branches of Chemistry

Biochemistry – study of substances and processes occurring in living things

Theoretical chemistry – use of mathematics and computers to design and predict the properties of new compounds.

Analytical chemistry – identification of the components and composition of materials.

What is a chemical? Any substance that has a definite

composition. Examples: sugar, toothpaste, salt, ATP Chemical unnatural

Why is research important?

So that we can understand the world around us and how things work

So that we can make things that help people So that we can improve the way things work Many reasons that research is important!

Basic Research

Basic Research – to increase knowledge. Driven by curiosity Main motivation is to expand man’s

knowledge, not to invent or create something Often, basic research results in chance

discoveries.

Basic Research

Examples of basic research questions How did the universe begin? What are protons, neutrons, and electrons

composed of? How do slime molds reproduce? What is the specific genetic code of the fruit

fly?

Applied Research

Applied Research – to solve practical problems of the modern world

Examples: improve agricultural crop production treat or cure a specific disease improve the energy efficiency of homes,

offices, or modes of transportation

Technological Development

Technological Development – production and use of products that improve our quality of life

Science is knowledge, and technology is the application of that knowledge for practical purposes.

Examples: Computers, non-stick cookware, fiber optics,

cellular phones, etc.

Which branch of chemistry?

designing new compounds using computer modeling ____theoretical ________

 investigating energy relationships for various reactions ____physical ________ 

comparing properties of alcohols with those of sugars ____organic _________

studying reactions that occur during food digestion____biochemical__________

carrying out tests to identify unknown substances____analytical __________

What type of research?

A new drug is created to cure a disease __applied research___________

Man-made element #115 is created by Russian scientists ___basic research

Intel creates a faster computer chip applied research

Mobile phone service began in 1946 by AT&T technological development

Section 1-2: Matter and Its Properties

What does everything you see around you have in common?

Matter

EVERYTHING you see around you has two basic things in common…it takes up space, and it “weighs” something.

VOLUME - is the amount of three dimensional space an object occupies. Everything you see has a volume.

MASS - is a measure of the amount of “stuff” in that space (volume). How much “stuff” an object has or is made up of.

Matter

Matter is anything that has mass and takes up space (i.e., volume)

In other words, it’s the “stuff” that makes up the universe

Mass vs. Weight

What is the difference between MASS AND WEIGHT?

Mass vs. Weight

WEIGHT is a measure of the earth’s gravitational attraction for matter. How hard the earth pulls on an object.

MASS is a measure of the quantity of matter. How much “stuff” is in an object.

Mass vs. Weight

A rock has a mass of 50kg and weighs 110 lbs.

On the moon, the same rock has a mass of _50__kg and weighs __18.3__lbs.

Mass doesn’t change, weight depends on gravity.

In chemistry, we will be dealing with MASS.

What makes matter?

ATOMS - The smallest unit of an element that maintains the properties of that element.

ELEMENT - Is a pure substance made of only one kind of atom.

What do you get when you combine Iron (Fe) and Oxygen (O)? You get the COMPOUND rust (Iron III Oxide). A COMPOUND is a substance that is made

from the atoms of two or more elements that are chemically bonded. (you cannot take it apart by physical means)

A MOLECULE is the smallest unit of an element or compound that retains all of the properties of that element or compound.

The way we can identify unknown substances is by noting their characteristics or properties

Usually, if not always, it is necessary to use several properties in order to identify a substance.

Properties are either intensive or extensive.

Extensive vs. Intensive properties

EXTENSIVE - depend on the amount of matter present (mass, length, volume, etc.)

INTENSIVE - do not depend on the amount of matter present (melting point, boiling point, density, ductility, malleability, color, temperature, etc.)

PROPERTIES AND CHANGES OF MATTER

PROPERTIES - Are characteristics that enable us to distinguish one kind of matter from another.PhysicalChemical

PHYSICAL PROPERTIES

Can be observed or measured without altering the identity of a material. Described both quantitatively (#’s) and

qualitatively (descriptions)Examples: odor, color, volume, state,

density, length, melting point, boiling point, etc.

PHYSICAL CHANGE

Is any change in a property of matter that does not result in a change in identity of the substance.EX. Tearing paper, grinding a rock into

sand, boiling water, melting iron, etc.

Changes of state

Is a physical change of a substance from one state to another.

States of Matter

Solid - has a definite volume and definite shape.

States of Matter

Liquid -Has a definite volume but an indefinite shape.

States of Matter

Gas - Has neither definite volume nor definite shape.

States of Matter

Gas has the highest kinetic energy, solid lowest.

SOLID

LIQUIDGAS

Melting

Freezing

Sublimation

Boiling or Evaporation

Condensation

Deposition

CHEMICAL PROPERTIES Refers to the ability of a substance

to undergo a change that alters its identity (changes into different substances)

Chemical properties are observed when substances are converted to new substances with different characteristic properties.

Chemical Change (Chemical Reaction.)

Any change in which one or more substances are converted into different substances with different characteristic properties.

Reactants (Reagents)

The substance or substances that react in a chemical change

Products

The new substance or substances that are formed by the chemical change.

EX. Sodium + Chlorine Sodium Chloride

(table salt) Solid sodium metal plus chlorine gas reacts

to yield (or form) solid sodium chloride (table salt)

Reactants Products

Lawexpressed using either equations or

statements that describe “accurately” behaviors in nature.

Law of Conservation of Matter

Matter cannot be created nor destroyed by ordinary chemical or physical changes

In 1905 Einstein developed his ideas concerning particles moving at or near the speed of light...result E = mc2

C = 3.0 x 108 meters/second

Energy Is the ability to cause change or the

ability to do work.2 types, kinetic and potential

Kinetic EnergyEnergy of motion. for example: Brownian Motion, a

moving car, a bullet shot from a gun, etc.

Potential EnergyEnergy that an object has because

of its position or composition “Stored Energy”

i.e. gasoline, water behind a dam, a rock on top of mountain, etc.

Law of Conservation of Energy

Energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical changes.

Classification of Matter

All matter can be “lumped” into one of two categories: Mixtures or pure substances

Mixtures

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

Kool Aid, candy bar, cookies, alloys. Alloys are mixtures of metals. Examples:

14K gold, 18K gold, brass, bronze, steel, etc.

Tw o typ es o f M ix tu res

Hom og en eou s -Mixtu res th at are u n iform in com p osition

H eterog en eou sM ixtu res th a t a re n o t u n ifo rm in com p os iton

M ixtu res

Pure Substances

Has a fixed composition and differs from a mixture in the following ways: 1. Every sample of a given pure substance has

exactly the same characteristic properties. 2. Every sample of a given pure substance has

exactly the same composition.

HomogeneousMixtures

HeterogeneousMixtures

Is thecomposition

uniform?

Mixtures

Compounds Elements

Can it be decomposedby ordinary

chemical means?

Pure substances

Can it be separated?

Matter

Yes No

Yes Yes NoNo

Burnt Sugar

SO WHAT EXACTLY IS THE DIFFERENCE BETWEEN A MIXTURE, A COMPOUND, AND A PURE SUBSTANCE?

LET’S DO A DEMOOOOOOOOOOOO!

Assignment Handouts:

Section 1-2 Textbook Problems1-2 Chapter Review Problems

Due Thursday BOP

Read “Secrets of the Cremona Violins” pg. 19

Chemical or Physical change?

crushing a can   melting an ice cube   boiling water   mixing sand and water   breaking a glass   dissolving sugar and water   shredding paper   chopping wood   mixing red and green marbles   sublimating dry ice

Chemical or Physical change?

rusting of iron   combustion (burning) of wood   metabolism of food in the body   mixing an acid and a base, such as hydrochloric acid (HCl)

and sodium hydroxide (NaOH)   cooking an egg   digesting sugar with the amylase in saliva   mixing baking soda and vinegar to produce carbon dioxide

gas   baking a cake   electroplating a metal   using a chemical battery

Some questions…

Select all of the following that could represent a chemical change.

Formation of gas Color change Heat given off Dissolving Formation of a solid Breaking Rusting

Which of the following is a chemical property? Choose only one.

Soft and fluffy Paper has the ability to burn     Water boils at 100 degrees C Density = 1 g/ml Green

Select the following items that are homogeneous.

distilled water granola bar Brass chocolate chip cookies bronze statue beach sand