Chemistry Chapter 1 Quiz

Law vs. Theory

• Laws describe a body of facts, while theories explain a body of facts.

States of Matter

• Solids: Atoms are in a fixed shape, vibrating.
• Liquids: Atoms take shape, more hitting.
• Gases: Atoms all over, most space.

Homogenous vs Heterogenous Mixtures

• Homogenous: Solution (e.g., steel, milk)
• Heterogenous: Mixture (e.g., blood, brass)

Separation Methods

• Filtration: Coffee filter
• Distillation: Heating flask
• Chromatography: Ink separation
• Electrolysis: Compounds into elements (e.g., H₂O)

Density

• Density (D) = mass (m) / volume (V) or V = m/D or m = D x V

Extensive vs Intensive Properties

• Extensive properties depend on the amount of substance (e.g., mass, volume, heat).
• Intensive properties do not depend on the amount of substance (e.g., melting point, boiling point, density).

Physical vs Chemical Changes

• Physical change: Alterations in a substance's physical properties (e.g., melting, boiling).
• Chemical change: Alterations that create new substances by rearranging atoms (e.g., reactions, burning).

Kinetic vs Potential Energy

• Kinetic Energy: Energy of motion (e.g., thermal, mechanical, electrical, acoustic).
• Potential Energy: Stored energy of position or status (e.g., gravitational, electrostatic, chemical, nuclear).

Law of Conservation of Energy

• Endothermic: Absorbs heat
• Exothermic: Emits heat

Qualitative vs Quantitative

• Qualitative: Physical appearance or feel.
• Quantitative: Numbers or units.

Temperature Conversions

• °C + 273.15 = K
• K - 273.15 = °C

Precision vs Accuracy

• Precision: How close measurements are to each other.
• Accuracy: How close measurements are to the true value.

Relative Error

• Relative error = (observed value - accepted value) / accepted value x 100%

Percentage Yield

• % yield = (actual yield / theoretical yield) x 100%

Significant Figures (Sig Figs)

• Rules for addition/subtraction: Least significant decimal place after the decimal point
• Rules for multiplication/division: Least significant figure present

Scientific Discoveries

• Rutherford: Atomic nucleus
• Millikan: Electron charge
• Thomson: Charge/mass ratio of electron
• Dalton: Atomic weight
• Becquerel/Curie: Radiation (radioactivity)

Atomic/Mass/lonic Numbers

• Atomic number (# of protons)
• Mass number (# of protons + neutrons)
• lonic charge: Ions
• Protons → lonic charge
• Proton + Neutrons

Isotopes

• Atoms of the same element with different numbers of neutrons
• (relative abundance) x (atomic mass) / 100.
• Sum it to find X

Periodic Table Trends

• Electronegativity increases across a period and decreases down a group, reflecting the tendency to gain electrons
• Ionic compounds: Metal + nonmetal, roman numerals.

Covalent Compounds

• Nonmetal + nonmetal (prefixes: mono, di, tri, tetra, penta, hexa, hepta, octa, and nona,deca).

Oxidation States

• Oxidation state: The charge an atom would have if all bonds were ionic.
• Free elements have an oxidation state of 0.
• Fluorine is always -1.
• Oxygen is usually -2.
• Group 1: +1, Group 2: +2, Group 3: +3.
• Hydrogen is usually +1; with nonmetals, +1; with metals, -1

Oxidation-Reduction (Redox) Reactions

• Oxidation: Loss of electrons
• Reduction: Gain of electrons
• Oxidizing agent: Substance causing oxidation
• Reducing agent: Substance causing reduction

Acid-Base Reactions

• Acids react with bases to produce water and a salt.
• H₂SO₄ + NaOH → H₂O + Na₂SO₄.

Stoichiometry

• The quantitative relationships between reactants and products in a chemical reaction (balancing).
• Limiting reactant: The reactant that is completely used up first in a reaction

Molarity

• Moles of solute / Liters of solution

Percent Composition

• % element = ((Molar mass of element) / (Molar mass of compound)) × 100

Empirical Formula

• Simplest whole-number ratio of atoms in a compound

Molecular Formula

• Actual number of atoms of each element in a molecule

Gram-Molecular Mass

• The mass in grams of one mole of a substance. (Molar Mass)

Mole Conversions

• Moles = mass / molar mass
• Moles = number of particles / Avogadro's number

Photons

• E photon = hc / λ

Electromagnetic Radiation

• The energy-carrying waves; radio-infrared-microwaves-visible-ultraviolet-x-rays-gamma
• Wavelength-Frequency

Bohr Theory

• Electron orbits around the nucleus.

Electron Configurations

• Arrangement of electrons in orbitals and sublevels
• Quantum numbers (n, l, ml, and ms).

Hybridisation

• The concept of hybridization describes the mixing of atomic orbitals in an atom to form hybrid orbitals that participate in chemical bonding.