Physical Science 1.1

• The universe is composed of 73% hydrogen, 25% helium, and 2% other elements.
• The Big Bang Theory explains the universe's origin as a rapid expansion from a singularity. The universe is calculated to be 13.7 billion years old.

First 3 Minutes of Big Bang

• Nuclear reactions began to form elements through the collision of protons and neutrons, forming isotopes.
• The early universe was hot enough to form tritium, the third isotope of hydrogen, along with hydrogen, helium, and lithium.

Nucleosynthesis

• Light elements (H, He, Li) formed by combining simple nuclei under extreme heat and pressure.

Stellar Nucleosynthesis

• Elements heavier than Beryllium (Be) to Iron (Fe) formed as the universe cooled, with protons and neutrons fusing into heavier nuclei.
• Hydrogen and most helium were made 100 seconds after the Big Bang, along with a small amount of lithium.
• Stars cease nuclear reactions at iron due to iron's stability and lack of neutron sources.

Supernova Nucleosynthesis

• Elements heavier than Iron (Fe) form during supernova events and take seven million years to fuse hydrogen and helium.
• Heavier elements like gold, mercury, and platinum are expensive due to their formation process.

Life Cycle Comparison

• Protostar corresponds to a fetus.
• Fusion ignition-main sequence corresponds to baby-adult.
• Red giant/supergiant corresponds to middle age.
• White dwarf corresponds to old age-death.

Greek Philosophers

• Empedocles (450 B.C.) believed all matter is made of earth, water, air, and fire and is credited with the idea that “Nothing comes from nothing”.
• Leucippus & Democritus proposed that matter is made of atoms, indivisible and uncuttable building blocks, where atomos means "not to be cut".

More Philosophers

• Plato (360 B.C.) coined the word "element" relating earth to a hexahedron/cube, water to an icosahedron, air to an octahedron, fire to a tetrahedron/ether.
• Aristotle (350 B.C.) modified an earlier theory that matter was made of four "elements": earth, fire, water, and air, and proposed that matter was continuous.

Alchemists' Contribution

• Alchemists identified metal elements like mercury, iron, and gold, and began investigating how materials could be changed.
• John Dalton, in 1808, proposed a modern atomic model based on experimentation: all matter is made of atoms, atoms of an element are identical, atoms are rearranged during chemical reactions, atoms of different elements combine in constant ratios, and atoms of one element cannot change into another.

Parts of an Atom

• Atoms have three parts: Protons (positive), neutrons (no charge), and electrons (negative).
• Protons and neutrons are found in the nucleus, and the electrons orbit the nucleus.

Development of Atomic Theory

• J.J. Thomson (1904) proposed atoms are made of electrons scattered within an elastic sphere of positive charge, called the "plum pudding model" and won a Nobel Prize in 1906
• Ernest Rutherford determined that all space in the center of the atom has a positively charged region called the nucleus.
• Henry Moseley used X-rays to study the sequence of chemical elements in Mendeleev's periodic table and demonstrated elements arrange by their atomic number.
• Niels Bohr improved the planetary model, electrons can be excited and move energy levels when energy is added. (Rutherford-Bohr Planetary Model)
• Erwin Schrodinger developed the quantum mechanical model.

Nuclear Reactions

• Alpha emission is represented by α or 2/4He
• Beta emission is represented by β, β-, or 0/-1e
• Positron emission is represented by β+ or 0/1e

Electronegativity

• Electronegativity (EN) measures the tendency of an atom to attract electrons chemically.

Covalent Bonds

• There are 3 classifications of covalent bonds: polar, nonpolar, and ionic.
• A Polar Covalent Bond involves unequal sharing of electrons (ΔEN: 0.5-1.7).
• Nonpolar Covalent Bonds occur when elements have the same electronegativity values (ΔEN < 0.4).
• Ionic Covalent Bonds have a ΔEN over 1.7.

Polar vs Nonpolar molecules

• Polar molecules have bonds that do not cancel out, making one part more negative than the other, and are hydrophilic (water-loving).
• Nonpolar molecules, equal sides, geometrically symmetrical, allowing polar bonds to cancel and is hydrophobic (water-fearing).

Dipole Moments

• Dipole moments measure of polarity, represented by an arrow pointing to EN atoms.
• Intermolecular forces are alternative forces between neighboring molecules.
• Intramolecular forces hold atoms together in a molecule.

Intermolecular Forces

• Intermolecular forces affect chemical properties which increase/decrease -Boiling point, melting point, viscosity, and surface tension increase as the strength of intermolecular forces increases. -Vapor pressure and volatility decrease with increasing strength of IMFA.

Examples of Intermolecular Forces

• Ion-Dipole forces are attractive forces between an ion and a polar molecule.
• Dipole-dipole forces bond polar covalent molecules together, where one end is partially positive and the other is partially negative.
• Hydrogen bonds are special dipole-dipole interactions between hydrogen atoms in a polar bond (N-H, O-H, or F-H) and an electronegative atom (O, N, or F).
• London Dispersion forces are weak attractive forces from temporary dipoles in atomsmolecules.

Physical Properties

• Boiling Point is the temp to vapor pressure of a liquid.
• Melting Point is the temp to make a solid into a liquid.
• Surface Tension is the energy needed to increase surface area
• Viscosity is the measurement of resistance of a liquid flow.
• Vapor is pressure substance in its gas state.
• Volatility is the evaporation ratio.

Biological Macromolecules

• Macromolecules are large molecules, such as polymers or proteins, consisting of smaller structural units.
• Polymers are long molecules of many building blocks
• Monomers are small building-block molecules with polymers/carbs being the three of the four classes of life's organic molecules

Synthesis/Breakdown

• Dehydration occurs when two monomers bond together through the loss of a water molecule
• Polymers turn into monomers through hydrolysis.

Carbohydrates

• Carbohydrates are a readily available source of short-term energy and are composed of hydrogen, oxygen, and colorless atoms (CHO)
• Glycogen is stored in the liver and muscle of animals, while starch stores energy in plants
• Monosaccharides are simple sugars (glucose, fructose, galactose).
• Disaccharides are two monosaccharides bound together (sucrose, lactose, or maltose).
• Polysaccharides are 3 or more monosaccharides (starch).

Lipids

• Lipids are storage energy, waterproof barrier, chemical messengers, and insulation that are hydrophobic and composed of fatty acids.
• There are two types of lipids: saturated fats and unsaturated fats. -Saturated fats are solid and unhealthy. -Unsaturated fats are missing at least one hydrogen.
• Oils are nonpolar molecules, including fats, oils, steroids, and waxes.

Proteins

• Proteins structure support (muscles, bone, hair, skin, nails, etc.), Enzymes (speeding up chemical reactions), Transport infection, and Hormones that are made of Hydrogen, carbon, oxygen, and Amino Acids that are protein that help to speed up transportation.

###Nucleic Acids

• Nucleic acids are biomolecules that contain the blueprints for making proteins.
• Nucleic acids store and transmit hereditary information (DNA), and aid in protein synthesis (RNA)

Collision of a Chemical Reaction, and Effects

• Collision theory states that atoms, ions, and molecules must collide to react.
• Factors include: frequency of collisions, energy with which particles collide, temperature, a catalyst, surface area of a solid, and concentration of a solution to form a balanced product.

Limiting Reagents

• Find moles of the reagents for an equation
• Divide to reach the limiting result, where the limiting reagent runs out first

###Percent Yield

• Theoretical yield is