Untitled Quiz

Introduction to Chemistry

• Science is well-tested knowledge based on observations and experiments.
• Chemistry is the branch of science concerned with matter, its composition, properties, and reactions.
• Chemistry also deals with the study of matter's changes.

Atoms

• Atom is the smallest part of a substance that cannot be broken down chemically.
• Atoms consist of a nucleus (center) composed of protons (positive particles) and neutrons (neutral particles) with electrons (negative particles) orbiting the nucleus.
• Atoms are also classified by the number of protons they have.

Types of Molecules

• Monatomic molecules: Made of a single atom, examples are noble gases.
• Diatomic molecules: Made of two atoms of the same or different elements, e.g. N2, Cl2, HCl, NO, CO.
• Polyatomic molecules: Made of more than two atoms, e.g., triatomic like H2O, SO2, O3; tetraatomic like BF3, SO3, NH3, P4.

Substances

• Substances: Pure matter with uniform composition and a fixed melting and boiling point, classified as elements and compounds.
• Elements: A substance made of atoms with the same atomic number.
• Compounds: Two or more elements chemically combined in fixed proportions.

Mixtures

• Mixtures: A matter composed of two or more substances that are not chemically combined.
• Mixtures can be homogeneous or heterogeneous, depending on their uniform composition.

Atomic Number and Mass Number

• Atomic number (Z): The number of protons in the nucleus of an atom.
• Mass number (A): The total number of protons and neutrons in an atom's nucleus.
• Isotopes: Atoms of the same element with different mass numbers due to differing neutron numbers (while having the same number of protons).

Chemical Symbols

• Chemical symbols are shorthand representations of elements.
• Elements are represented by one or two letters of their name, with the first letter capitalized.

Chemical Formulas

• Chemical formula is a shorthand notation for compounds, showing the number of each type of atom.
• Molecular formula represents the actual number of atoms in a molecule of a substance.
• Empirical formula represents the simplest whole number ratio of atoms in a compound.
• Structural formula represents the arrangement of atoms in a molecule.

Solutions

• A solution is a homogeneous mixture of one or more solutes dissolved in a solvent.
• A binary solution is a solution formed by mixing two substances.
• Solute is the substance that dissolves to produce a homogeneous mixture.
• Solvent is the substance in which a solute dissolves to produce a homogeneous mixture.
• Supersaturated solution is a solution that contains more solute than a saturated solution at a temperature.
• Dilute solution contains a small amount of solute.
• Concentrated solution contains a large amount of solute.
• Concentration is the amount of solute present in a given volume of solvent.

Acids, Bases, and Salts

• Acids are substances that release hydrogen ions (H+) in aqueous solutions.
• Bases are substances that release hydroxide ions (OH-) in aqueous solutions.
• Salts are substances formed by the reaction of an acid and a base.
• There are different theories about acids and bases (Arrhenius, Lowry-Brønsted, and Lewis).

Electrolytes

• Electrolytes are substances that allow electric current to pass through them in dissolved or molten state.
• Strong electrolytes completely dissociate into ions in solution.
• Weak electrolytes partially dissociate into ions in solution

Electrochemical Cells

• Electrochemical cells are systems in which chemical energy is converted into electrical energy or electrical energy is converted into chemical energy.
• Electrolytic cells use an external current to drive a non-spontaneous chemical reaction.
• Galvanic cells produce an electric current from a spontaneous chemical reaction.

Water Cycle

• Water is essential for life on Earth.
• Water continuously circulates through the atmosphere, land, and bodies of water, via evaporation, condensation, precipitation/runoff, and infiltration.
• Water is important for human survival (drinking water, agriculture).

Water Properties

• Water is a polar molecule, meaning it has a slightly positive end and a slightly negative end.
• Water molecules can form hydrogen bonds and other molecules.
• Water has high heat capacity, heat of vaporization, and surface tension.
• Water exist in three states — solid, liquid and gas
• Water's density is an unusual property.

Water Hardness

• Hard water is water that does not readily produce lather with soap and contains dissolved minerals/cations.
• Soft water is water that readily produces lather with soap.
• There are two main categories of hard water (temporary and permanent) which can be softened via different processes

Urinalysis

• Urinalysis is a medical test that examines urine for various substances.
• Urinalysis helps diagnose or monitor different health conditions (e.g., urinary tract infections, diabetes, kidney disease).

Lipids

• Lipids are hydrophobic organic compounds (fatty acids, triglycerides, phospholipids, steroids, and waxes).
• Lipids are an important structural component of cell membranes in living organisms.
• Lipids store energy and provide insulation to the body.

Proteins

• Proteins are polymers made of amino acids.
• Proteins play many crucial roles.
• Proteins are categorized by functions and shape.