CHEM 10.01 Reviewer PDF

MODULE 1.1 SCIENCE AND THE SCIENTIFIC METHOD Science is a: ​ Perspective (A way to look at the natural world) ​ Practice (An application) ​ Institution (A consensus of expert ideas) Science: ​ Has assumptions and limitations ​ Cannot be explained by Gods or ghosts ​ Is not static...

MODULE 1.1 SCIENCE AND THE SCIENTIFIC METHOD Science is a: ​ Perspective (A way to look at the natural world) ​ Practice (An application) ​ Institution (A consensus of expert ideas) Science: ​ Has assumptions and limitations ​ Cannot be explained by Gods or ghosts ​ Is not static nor perfect–not absolute, it is dynamic ​ Is a social exercise–scientists collaborate The Theory of Spontaneous Generation ​ Living organisms could arise from nonliving matter (articulated first by Aristotle) ​ Francesco Redi disproved this theory in 1668 ​ Louis Pasteur fully disproved the theory in 1862. He said “Life only comes from life.” Thinking Scientifically vs Unscientifically Scientific Unscientific ​ Critical thinking and healthy ​ Disregards logic and methodology of skepticism scientific practice ​ Collective wisdom ​ Inflexible ​ Based on the principles of its practice, ​ Authority based on unverifiable belief not claims ​ Unable to criticize and accept criticism ​ Rejects perspective different from their own The Scientific Method ​ It is a process; a way of learning ​ Many methods, no clear form ​ Non-linear, you can start anywhere *Perception precedes understanding. Perception is the key element to acceptance. Discovery - lies between hypothesis and serendipity Categories of Scientific Investigation ​ Observation Investigation → uses all senses to explore ​ Controlled What-if? Experiment → requires controlled data to compare with new data ​ Explanation-seeking Experiment → looking for an explanation for the phenomena ​ Modelling What-if? Experiment → requires assumptions to make predictions ​ Problem-solving Approach → action to accomplish the investigation  MODULE 1.2 SCIENTIFIC MEASUREMENTS IN THE OLD DAYS: ​ Grains of barley or corn for the mass of metals ​ Cubit = length of the forearm from elbow to tip of middle finger ​ Mille Passus = 1000 paces of Roman feet ○​ Problem: everyone’s forearms and feet had different lengths PRESENT TIME: International System of Units (1960, 7 standardized units for different quantities) ​ Time ​ Length ​ Mass ​ Electric current ​ Thermodynamic temperature ​ Amount of substance ​ Luminous intensity Accuracy - how close data is to true value Precision - how close data points are to each other Uncertainty in Measurements ​ All measurements are not accurate ​ Degree of uncertainty → ± (e.g. a graduated cylinder’s degree of uncertainty ±1mL) Parallax Error - change in apparent position of an object when viewed from different points Significant Figures (Sig Figs) ​ Digits in a measurement that contribute to its PRECISION ​ Includes the uncertain digit at the end Rules to follow for Sig Figs: ​ Non-zero digits are always significant → 4300 = 2 sig figs ​ Any zeros between two significant digits are significant → 5003 = 4 sig figs ​ A final zero or trailing zeros in the decimal portion only are significant ​ → 512.0000 = 7 sig figs ​ → 3000. = 4 sig figs ​ → 0.00010540 = 5 sig figs *year 2025 is not a measurement, infinite sig figs Calculating with Sig Figs: Multiplication/Division → 1.2 x 3.54 = 4.248 Then round it off according to the value with the least number of sig figs = 4.2 ✓ Addition/Subtraction → 1.234 + 5.6 = 6.834 Round off according to the value with the least number of decimal places = 6.8 ✓ In rounding off, REMEMBER! ❖​ Multiplication/Division → least # of sig figs ❖​ Addition/Subtraction → least # of decimal places Exercise: 4.3 x 9.624 + 10.42 = 51.8032 = 51 ✓ *apply the rules in every computation  MODULE 2.1 MATTER Matter is anything that has mass and occupies space. It can exist in several states. States of Matter 1.​ Solid - strong forces of attraction; closely packed particles 2.​ Liquid - weak forces of attraction; loose particles 3.​ Gas - very weak forces of attraction; particles are far apart Phases of Matter Phase - distinct forms of the states of matter State = Phase ↓ Solid = Ice Liquid = Water Gas = Vapor Difference of State and Phase State - relates to particle distance Phase - relates to different properties within states Properties of Matter Physical Chemical ​ Observed without changing matter ​ Observed when matter reacts with (color, temperature, and mass) another type of matter ​ Can be observed without any ○​ Combustion undergoing change ○​ Oxidation (e.g. Rusting) ​ Can only be observed when undergoing a chemical change Changes of Matter Physical Chemical ​ Change in physical appearance ​ Change in composition of matter that without altering the composition of is different from the original matter composition ○​ e.g. Melting ice, Folding paper ○​ e.g. Rusting, Metabolism, Burning wood  Classifications of Matter Substances Mixtures ​ Elements ​ Homogenous ○​ Most basic form of matter; ○​ Cannot be separated cannot be broken down into mechanically simpler substances ​ Heterogenous ○​ e.g. Atoms (Monatomic ○​ Can be separated Elements) and Molecules (Two mechanically or more atoms) ​ Compounds *mixtures are any combination of substances ○​ Combination of two or more elements  MODULE 2.2 ATOMS Leucippus & Democritus ​ Greek philosophers that thought there was a certain particle that could not be cut up anymore and that it is the smallest particle ​ Atom - “a tomos” (Greek word): indivisible ○​ Smallest particle of matter 2200 years: ‘Death of Chemistry’ ​ 400 BC to 1780s ​ NO new discoveries ​ People believed what Ancient Greek philosophers had said about matter ○​ “All matter was made out of four elements: Fire, Air, Earth, and Water.” - Aristotle Antoine Lavoisier (Father of Modern Chemistry) ​ Law of Conservation of Mass ○​ Mass is neither created nor destroyed ○​ Appearance may change, but mass is still the same ○​ The total mass of the products must come from the mass of the reactants ​ Oxygen Theory of Combustion Joseph Proust ​ Comparison of natural and artificial copper carbonate ​ Same composition by mass ​ Law of Definite Proportions ○​ A compound has a set of proportion of elements ○​ Compounds always contain the same elements in the exact same proportions by mass Jöns Jacob Berzelius ​ One of the founders of Modern Chemistry ○​ Discovered several elements (cerium, selenium, thorium) ​ Gave credit to Proust in 1812 John Dalton ​ Another founder of Modern Chemistry ​ Billiard Ball Model ○​ All matter is composed of extremely small particles called atoms ○​ Atoms cannot be subdivided, created, nor destroyed; in chemical reactions, atoms are combined, separated, or rearranged ○​ Elements are made of just one TYPE of atom that is unique to that element ○​ Compounds are formed when atoms of different elements combine in fixed proportions  ​ Law of Multiple Proportions ○​ When two elements combine with each other to form two or more compounds, the ratios of the masses of one element that combine with the fixed mass of the other are simple whole numbers. ○​ Elements can combine in different ratios, resulting to a different compound depending on the ratio Eugen Goldstein ​ Discovered Canal Rays (light emitted from the positive electrode) Cathode Ray - negative electrode or Cathode; Cathode Rays consist of charged particles allowing it to be deflected or bent by magnetic or electric fields Canal Ray - positive electrode or Anode J.J. Thomson ​ Cathode Rays consist of charged particles called “corpuscles” aka electrons ​ Plum Pudding Model ○​ Theorized that atoms are divisible ​ Electrons are scattered in a positively charged space ○​ First atomic model to include subatomic particles Robert Millikan ​ Determined and calculated the charge of a single “corpuscles” ​ Electrons are negatively charged particles Ernest Rutherford ​ Discovered Alpha and Beta particles, the Nucleus, the Nuclear Model, and the Gold Foil Experiment ​ Nuclear Model ○​ Atoms consist mostly of empty space; concentrated positively charged nucleus (consisting of protons) ○​ Electrons orbit around the nucleus ○​ Alpha particles → positively charged; Beta particles → negatively charged Niels Bohr ​ First to apply Quantum Theory ​ Planetary Model ○​ Theorized that electrons would orbit at different energy levels, first atomic model to use quantum theory Erwin Schrödinger ​ Formulated Schrödinger’s Equation ○​ A partial differential equation that describes the wave function of a quantum-mechanical system ​ ĤΨ = EΨ ○ Ĥ= hamiltonian operator ○ Ψ= wave function ○ E= energy ​ Quantum Model ○​ Wave functions provides the probabilities of where electrons can be around nucleus aka electron cloud model ○​ Most widely accepted model of the atom ​ Clouds of Probability = Orbitals ○​ Where electrons are likely to be found ○​ within each shell of an atom there are combinations of orbitals (subshells) James Chadwick ​ Discovered a different particle with no charge as part of the nucleus; neutrons Subatomic Particles ​ Every atom has Electrons surrounding the Nucleus containing Protons and Neutrons 1.​ Electrons (e-) ​ Negatively charged unit of atom, much tinier than other subatomic particles 2.​ Protons (p+) ​ Positively charged unit of atom; does not move; characterizes an element 3.​ Neutrons (n) ​ Neutral unit of atom Nucleus → Protons + Neutrons Formulas: ​ Charge = Protons - Electrons ​ Neutrons = Mass Number - Protons ​ Mass Number = Protons + Neutrons ​ Atomic Number = # of Protons ​ Electrons (Neutral) = # of Protons ​ Electrons (if charge if -1) = Protons + 1 Isotopes ​ Atoms of an element with a different mass number ○​ Number of protons are always the same, but number of neutrons may vary Ions ​ Charged atoms; stable form of atoms ​ Disproves a Dalton’s atomic theory ○​ Elements are NOT made of just one type of atom that is unique to that element ​ Cation & Anion ○​ Cation → atom with more protons than electrons–excess positive charge ○​ Anion → atom with more electrons than protons–excess negative charge  MODULE 3.1 THE PERIODIC TABLE Discovery of Elements (18th to 19th Century) ​ Triadic relationship according to atomic mass ​ Every 7th element had similar properties, later discovered to be every 8th element after the discovery of Noble Gases = “Law of Octaves” Dmitri Mendeleev (Father of the Modern Periodic Table) ​ Organized the elements by atomic mass ​ Observed patterns while arranging elements ​ Theorized the properties of missing elements Atomic Radius - distance between nucleus and outermost electron Ionization Energy - energy needed to be absorbed by an atom to release an electron Electronegativity - tendency of atoms to attract electrons  MODULE 3.2 ELECTRON CONFIGURATION States of an Electron GROUND STATE EXCITED STATE ​ Lowest energy level in an atom ​ Energy levels above the ground state ​ Nearest to the nucleus ​ Where electrons are when an atom ​ Where electrons are when no energy absorbs a quantum of energy has been absorbed Electron Configuration ​ Arrangement of electrons in the orbitals of an atom ​ Describes where electrons can be found around the nucleus Aufbau Principle - electrons fill the orbital with the lowest energy first Electron Configuration & Atomic Radius ​ As more electrons fill the orbital, the protons pull the electrons inward more, causing a decrease in the radius Ionization Energy - the more electrons in the outermost shell, the harder it is to move Electronegativity - The closer the shell is to being filled, the easier it is to attract an electron