Chemistry Fundamentals Quiz

Chemistry Fundamentals

• Chemistry is the study of matter, encompassing solids, liquids, and gases.
• Matter is anything that occupies space.

Changes in Matter

• Physical change: a transformation without altering chemical structure (e.g., wood to wood chips).
• Chemical change: results in the formation of new substances (e.g., burning wood).

Elements and Atoms

• Elements are substances that cannot be simplified further; they consist of millions of atoms.
• Four primary elements (Carbon, Hydrogen, Oxygen, Nitrogen - CHON) constitute 96% of body weight.
• An atom is the smallest unit of an element, made of protons (+), neutrons (0), and electrons (−).

Atomic Structure

• Atomic number indicates the count of protons in an atom's nucleus.
• Atomic weight is the sum of protons and neutrons in the nucleus.
• Isotopes differ in atomic weight but have the same atomic number (e.g., heavy hydrogen).

Chemical Bonds

• Molecules form when two or more atoms bond (e.g., O2, H2O).
• Chemical bonding is driven by the desire of outer shells to achieve stability (8 electrons).
• Ionic bonds involve the transfer of electrons, stabilizing the atoms involved.
• Covalent bonds entail the sharing of electrons between atoms, creating strong connections.

Organic and Inorganic Chemistry

• Organic chemistry focuses on carbon-containing compounds.
• Inorganic chemistry deals with non-carbon substances.

Water and Its Importance

• Water is considered the universal solvent and plays critical roles in temperature regulation, lubrication, and chemical reactions.

Ions and Electrolytes

• Ions are charged particles, which can be cations (positively charged) or anions (negatively charged).
• Important cations include Na+ (sodium), Ca2+ (calcium), Fe2+ (iron), H+ (hydrogen), K+ (potassium), and NH4+ (ammonium).
• Key anions include Cl− (chloride), HCO3− (bicarbonate), and PO4^3− (phosphate).
• Electrolytes conduct electrical charges, crucial for bodily functions.

pH and Acid-Base Balance

• The pH scale measures acidity and alkalinity, with 7 being neutral.
• Normal blood pH ranges between 7.35 and 7.45; values outside this can indicate acidotic (pH < 7.35) or alkalotic (pH > 7.45) conditions.
• Buffers help regulate pH by neutralizing excess acids and bases.

Energy and Its Forms

• Energy is the capacity to perform work and exists in various forms:
  • Mechanical energy causes physical movement.
  • Chemical energy is stored in chemical bonds.
  • Electrical energy results from charged particle movement.
  • Radiant energy travels in waves, such as light.
  • Thermal energy transfers due to temperature differences.
  • Nuclear energy is released during radioactive decay.

Mixtures

• Mixtures combine two or more substances that can be separated by physical methods.

Summary of Atoms and Charges

• Protons carry a positive charge, neutrons have no charge, and electrons have a negative charge.
• Acidic substances (e.g., vinegar, lemon juice) display pH values below 7, while alkaline substances (e.g., soap, ammonia) have pH values above 7.
• Water has a neutral pH of 7, while stomach content is highly acidic (pH 1-4) and urine falls between pH 5-8.