AP Chem Unit 1

Chemistry is the study of _________________

matter and the changes it undergoes; everything around us.

Anything that has mass or takes up space.

Matter

Matter can be understood in terms of what?

Arrangement of atoms.

Matter that is definite and uniform in composition and volume.

Substance

Examples of substances

• Ozone

• TTX

• Water

• Diamond

• Sugar

• Lithium Metal

How is ozone formed?

Oxygen comes in contact with UV radiation and fuses together to make ozone.

In the mid-1980s, scientists detected thin areas in the ozone layer over Antarctica. What did they find to be the cause of those thin areas?

Chlorfluorocarbons (CFC’s)

What are CFC’s and what impact did they have on the ozone layer?

• CFC’s are chemicals used as coolants, propellants, etc

• They were considered safe and nontoxic, but that was soon proven wrong

• As they floated into the atmosphere, the, chlorines from the CFC would break down ozone into oxygen, thus destroying the layer

Define the following:

A) a measurement that reflects the amount of matter

B) A measure of mass and gravity’s force on an object.

A) Mass

B) Weight

What do we mean when we say that matter and its behavior is macroscopic?

It can be seen without a microscope.

The structure, composition, & behavior of all matter can be described on the ___________ level.

submicroscopic (atomic)

Verbal, visual, or mathematical explanation of experimental data.

Modeling

Identify the five branches of chemistry based on the following definitions:

1) carbon-containing chemicals

2) non-carbon containing chemicals

3) components and composition of substances

4) behavior and changes of matter

5) processes of living organisms

1) Organic

2) Inorganic

3) Analytical

4) Physical

5) Biochemistry

A systematic approach to pose and test solutions to questions, and assess the results of those tests

The Scientific Method

Steps of the Scientific Method

1) Observations

2) Hypothesis

3) Experiments

4) Conclusion

5) Revised Hypothesis

************************************************************

6) Theory

7) Experiments

8) Revised Theory

Qualitative vs Quantitative Data

Qualitative: relates to characteristics that can be observed through the 5 senses

Quantitative: numerical observations that explain how big/small/fast/slow etc.

A relationship in nature that is supported by many experiments and has no exceptions.

Scientific Law

Ex: Newton’s Law of Gravity

Pure vs Applied Research

Pure Research: knowledge for the sake of knowledge

Applied Research: addresses a specific goal

When scientists receive results that are far from what was expected

Ex:

• Penicillin

• X-Rays

Chance Discovery

Define the three states of matter

1) Solids

• have a definite shape and volume

2) Liquids

• have a definite volume but take the shape of their container

3) Gases

• have no definite shape or volume

The gaseous state of a substance that is a solid/liquid at room temperature.

Vapor

Two Properties of matter

Physical & Chemical.

Physical Properties of Matter can be observed without doing what? What are the two types?

They can be observed without changing the sample’s composition.

Two Types:

Extensive: dependent on the amount of substance present

ex: mass, length, volume

Intensive: independent of the amount of substance present

ex: density, color

Chemical Properties of Matter

Ability of a substance to combine w/ or change into one or more other substances.

Ex: iron forming rust; copper turning green in the air

A chemical reaction can simply be defined as:

Breaking bonds and forming new ones

Physical change

Alters a substance without changing it’s composition.

Ex: crumpling, cutting

Transition of matter from one state to another.

Phase change

5 Phase changes

1) Boiling

2) Freezing

3) Melting

4) Condensation

5) Sublimation

Chemical change

A change that involves a substance(s) turning into a new substance(s).

Examples of chemical changes

• Bubbling

• Change of smell

• Light

• Decomposing

• Rusting

• Exploding

• Burning

• Oxidizing

Law of conservation of mass

• states that mass is neither created nor destroyed in a chemical reaction, it is conserved

• mass of the reactants = mass of the products

• WHAT GOES IN MUST COME OUT

Combination of two or more pure substances in which each pure substance retains its individual chemical properties.

Mixture

Homogeneous vs Heterogeneous Mixtures

Homogeneous: mixture where the composition is constant throughout

Ex: Vinegar

Heterogeneous: mixture where the individual substances remain distinct

Ex: Salad dressing

Identify the 5 ways to separate mixtures based on the definitions.

1) Uses a porous barrier to separate solid from liquid in a heterogeneous mixture.

2) Uses the differences in boiling points of substances in homogeneous mixtures.

3) The formation of pure solid particles from a solution containing the dissolved substance.

4) Process of a solid changing directly to gas, which can be used to separate mixtures of solids when one sublimates and the other doesn't.

5) Separates the components of a mixture on the basis of the tendency of each to travel across the surface of another material.

1) Filtration

2) Distillation

3) Crystallization

4) Sublimation

5) Chromatography

Element

A pure substance that cannot be separated into simpler substances by physical or chemical means.

Ex: lithium; gold; sodium; zinc

How many natural elements occur on earth?

92.

Compound

A pure substance made up of two or more chemically combined elements.

Ex: salt; water; hydrogen peroxide

T or F: Elements can be separated, but compounds cannot

False; Elements cannot be separated, but compounds can be broken into components by chemical means.

Percent by Mass= mass of element/mass of compound x 100

Law of Definite Proportions

When different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in whole number ratios.

Law of Multiple Proportions

The change of the amount of substance in a chemical reaction over time.

Rate

The study of heat energy associated with a chemical reaction.

Thermochemistry

The state in which there are no observable changes as time goes by (observed on a macroscopic level).

Equilibrium

What are two things about matter that ancient scientists believed?

1. Matter was composed of such things as earth, water, air, and fire.

2. Matter could be endlessly divided into smaller and smaller pieces.

Greek Philosophers Democritus vs Aristotle

___________: 1st person to propose the idea that matter was not infinitely divisible, and was made up of individual particles called atomos (atoms).

_____________: disagreed w/ the other philosopher because he didn’t believe empty space could exist.

Democritus; Aristotle

Characteristics of matter according to Democritus

• Solid

• Homogeneous

• Indestructible

• Indivisible

The conservation of mass in a reaction is the result of the combination, separation, or rearrangement of atoms.

Dalton’s Theory

Characteristics of atoms according to Dalton

• Indivisible & Indestructible

• Atoms of a specific element are different from those of another element

• Different atoms combine in whole-number ratios to form compounds

The conservation of mass in a reaction is the result of the combination, separation, or rearrangement of atoms.

ATOM

Tool that allows individual atoms to be seen.

Scanning tunneling microscope (S.T.M)

Stream of particles carrying electrons.

Cathode Ray

The emission and transmission of energy through space in the form of waves

Radiation

Won the Nobel Prize in 1906 for identifying the first subatomic particle— the electron.

JJ Thomson; also responsible for plum pudding model

Charge of an electron

6.022 × 10^-19

Used the oil-drop apparatus to determine the charge of an electron.

Robert Milikan

Since the some of the alpha particles bounced back from the gold foil, he determined that 1. atoms are mostly empty space, and 2. the atoms’ positive charge most of its mass is contained in its center, the nucleus

Ernest Rutherford’s Gold Foil Experiment (leading to proton discovery)

Why did the alpha particles deflect in Rutherford’s Gold Foil Experiment

Because of the repulsive force between the positively charged nucleus and the positive alpha particles

Won the Nobel Prize in 1935 for his discovery of neutrons

James Chadwick

How do electrons travel around the nucleus

By their attraction to the nucleus’ positive charge

Protons and neutrons are composed of subatomic particles called _______

quarks.

Mass number

Sum of protons and neutrons.

Isotopes

Atoms with the same number of protons and different number of neutrons.

One atomic mass unit (amu) is defined as what?

1/12th of the mass of a carbon-12 atom.

Weighted average mass of the isotopes of an element.

Atomic mass

The chemical properties of an element are determined primarily by what subatomic particles?

Protons and electrons.

What type of reactions can change one element into another element?

Nuclear reactions.

When substances spontaneously emit radiation.

Radioactivity

When unstable nuclei lose energy by emitting radiation, forming a stable one.

Radioactive Decay

When an atom undergoes radioactive decay and emits an alpha particle.

Alpha radiation

Radiation that emits negatively charged particles called beta particles.

Beta radiation

What charge do beta particles have?

They are electrons/positrons with a positive charge

Radiation where a photon of energy is emitted from an unstable nucleus.

Gamma radiation

Gamma rays have no _____ and no _____

mass; charge.

_________ rays account for most of the energy lost during radioactive decay

Gamma

Atoms that contain too many or too few neutrons are ________ and _____ energy through radiactive decay to form a stable nucelus.

unstable; lose.

An element’s chemical behavior is related to the ________ of _______ in its atoms

arrangement; electrons.

The shortest distance between equivalent points on a continuous wave.

Wavelength

The number of waves that pass a given point per second.

Frequency

The wave’s height from the origin to a crest.

Amplitude

3.00 × 10^8 m/s

Speed of light

What natural phenomenon contains a continuous range of wavelengths and frequencies?

Sunlight

Prism

Separates sunlight into a continuous spectrum of colors.

Electromagnetic spectrum

Includes all forms of electromagnetic radiation.

A vibrating disturbance by which energy is transmitted.

Wave

2 Components of an electromagnetic wave

1) Electric Field

2) Magnetic Field

The electric and magnetic field have the same speed, but they travel in _______ planes.

perpendicular

Atoms and molecules emit energy only in certain discrete quantities, or quanta

Planck’s Quantum Theory

Quantum (E)

The minimum amount of energy that can be gained or lost by an atom.

Value of Planck’s Constant

6.626 × 10^-34 J x s

Einstein’s Photoelectric Effect

The phenomenon that occurs when electrons are ejected from a metal surface because a light of the threshold frequency shined on it.

The particles in a beam of light

Photons

In 1905, Albert Einstein proposed what?

The idea that light has particle-wave duality.

The set of frequencies of the electromagnetic waves emitted by the atoms of an element.

The Atomic Emission Spectrum

Who correctly predicted the frequency lines in hydrogen’s atomic emission spectrum?

Neil Bohr.

Ground state

The lowest energy state of an atom; most stable state

What state is an atom in when it gains energy?

An excited state.

Principal Quantum Number (n)

Indicates the relative size and energy of atomic orbitals.

Three types of Quantum Numbers

1) Principal Quantum Number

2) Angular Momentum Quantum Number

3) Magnetic Quantum Number

Identify the type of quantum number based on the definition:

1) Values 1,2,3 and so forth

2) Tells us the shape of the orbital (depending on the value of n)

3) Describes the ortientaition of the orbital in space

1) PQN

2) AMQN

3) MQN

What is the quantum number for the ground state of an electron?

n = 1; As energy is added, the quantum number increases.