General Chem 1 no. 2

• Solid

• Liquid

• Gas

• Plasma

State of Matter

Solid

-          Tightly packed particles

-          Kinetic energy is low

-          Definite shape

-          Definite volume

-          High density

-          Strong attraction

Attraction

Particles moving to each other

Repulsion

Moving away from each other

Density

The ability of a substance to float

Liquid

-          Indefinite shape

-          Definite Volume

-          Occupies space

-          Hydrogen ion is attracted to the metal

-          High density (compared to gases)

-          Flowability [like a wheel (the particles)]

-          Closely packed (but not arranged in a regular pattern like in solids)

-          Attraction (weaker than solids, but stronger than in gases

-          Kinetic energy à the particles have more energy than solids particles, allowing them to move and side past each other

Gas

 

-          Indefinite shape

-          Indefinite volume

-          Particles: far away from each other

-          Weak force of attraction

-          Random/independent (movement)

-          Collision energy increases temperature increases as well movement of gas particles also increases

-          Kinetic energy gas particles move rapidly in all directions with high kinetic energy

• Physical Property

• Chemical Property

Properties of matter

Physical Property

-          is a characteristic of a substance that can be observed or measured without changing its chemical composition or identity.

Extensive Property

-          Do depend on sample size

-          Ex. Volume, mass, size

• Extensive Property

• Intensive Property

Physical Property:

Intensive Property

-          Do not depend on the quantity of matter but quality

-          Ex. Include density, state of matter, and temperature

Chemical Property

-          Ability of a substance to undergo change to transform into a different substance

• Pure Substance

• Mixture

2 Types of Matter

Pure substance

-          No added substance/s

• Elements

• Compound

Pure Substance:

• Heterogenous

• Homogenous

Mixture:

Heterogenous

Physical appearance is observable

Homogenous

Uniform

• Solvent

• Solute

Solution:

Solvent

Dissolves solute

Solute

Being dissolved

• Colloids

• Suspension

Heterogenous Mixture

Colloids

Small particles

Suspension

(Big particles) mixture where particles we dissolve is still observable

Separation Techniques

-          Method that converts a mixture or solution of chemical substances into two or more distinct product mixtures

-          Scientific progress of separating two or more substance in order to obtain purity

• Decanting

• Sieving

• Filtration

• Evaporation

• Chromatography

• Distillation

Separation Techniques:

Decanting

-          a physical method of separating a liquid from a solid or another liquid by carefully pouring off the top layer without disturbing the bottom layer.

Sieving

-          Separating a mixture based on different sizes of components

-          Usually separated by hand

Filtration

-          Is a special form of sieving that separates very fine solid particles from liquid or gas mixtures

Evaporation

-          Is used for recovering dissolved solids from solutions. The solution is either boiled or simply left uncovered, Resulting in the evaporation of water and the crystallization of solutes

-          We get the solid

Vaporization

by-product where liquid turned into gas

Chromatography

-          Color

-          70% alcohol & 30% water

-          Is used to separate liquid or gas mixtures

-          separates substances because they travel at different speeds through a stationary material (such as paper).

Distillation

-          Is similar to evaporation, except that the evaporated substance, known as the distillate, is collected.

-          Evaporated substance is passed through a tube known as a condenser

-          We get the liquid

• John Dalton

• Michael Faraday

• William Crookes

• J.J. Thomson

• Ernest Rutherford

• Niels Bohr

• Erwin Shrödinger

People who contributed in Atoms

John Dalton

-          British chemist and physicist

-          Proposed the Solid Sphere Model in the early 19^th century

-          Shifted from philosophical ideas to scientific theory

-          First atomic model based on experimental evidence and quantitative observation

-          Paved the way for the development of modern atomic theories

Solid Sphere Model

-          Atoms are tiny balls, indestructible, same materials

isotopes

they have the same element but different masses

• Protons

• Neutrons

• Electrons

Subatomic Particles

Michael Faraday

• Nature of electricity

• An English Chemist who showed that there is a relationship between matter and electricity

William Crookes

-          Proved the idea of Faraday

-          Experiment = Cathode Rays is always attracted to the positive

Gas Discharge Tube Experiment

was performed to study how electricity behaves in gases. He used a glass tube with most of the air removed and placed two metal electrodes inside: a negative cathode and a positive anode. When a high voltage was applied, a beam called cathode rays traveled from the cathode to the anode.

 

Crookes observed that the rays traveled in straight lines, produced shadows when an object blocked them, and could even turn a small paddle wheel, showing that the rays carried energy and had mass. He concluded that cathode rays were made of tiny particles moving from the negative electrode to the positive electrode.

• Negative Cathode

• Positive Anode

Gas Discharge Tube Experiment two metal electrodes inside:

cathode rays

When a high voltage was applied, a beam called _______ traveled from the cathode to the anode.

J.J. Thomson

-          Used a similar experiment to prove that cathode rays are electrons, leading to the discovery of the first subatomic particle.

-          Nature of electrons

-          Proposed the Plum Pudding Model in the Late 19^th century

-          Discovered electrons

-          Understands from indivisible atom at subatomic particles

 

Ernest Rutherford

-          Nucleus in an atom

-          Nuclear Model

Gold Foil Experiment

To study the structure of the atom. He directed a beam of positively charged alpha particles at a very thin sheet of gold foil. Around the foil was a fluorescent screen that detected where the alpha particles landed.

 

Rutherford observed that most of the alpha particles passed straight through (neutron) the gold foil without changing direction. This showed that most of the atom is empty space. However, some particles were deflected, and a very small number bounced back toward the source (proton). This surprising result suggested that there was a tiny, dense, positively charged region inside the atom.

 

From these observations, Rutherford concluded that an atom has a small, dense, positively charged nucleus at its center, where almost all of its mass is concentrated.The electrons are found outside the nucleus, occupying the mostly empty space around it.

alpha particles

Gold Foil Experiment He directed a beam of positively charged ________ at a very thin sheet of gold foil.

neutron

Rutherford observed that most of the alpha particles passed straight through (_____) the gold foil without changing direction.

proton

However, some particles were deflected, and a very small number bounced back toward the source (_____).

Niels Bohr

-          Planetary Model

• K

• L

• M

• N

Niels Bohr shells

Erwin Shrödinger

-          Contribution to quantum mechanics

-          Proposed the Quantum Model

-          Wavelike structure

Quantized energy

means that electrons can only have certain fixed amounts of energy, not just any amount.

Light as wave

light travels in the form of electromagnetic waves. This explains why light can reflect, refract (bend), diffract (spread out), and interfere with other light waves.

Light as particle

light also behaves as tiny packets of energy called photons (4^th subatomic particle).

Photon

4th subatomic particle

Solid Sphere Model

John Dalton Model

Plum Pudding Model

J.J. Thomson Model

Nuclear Model

Ernest Rutherford Model

planetary model

Niels Bohr Model

Quantum Model

Erwin Shrödinger Model