Chemistry and Biology Lecture Notes Flashcards

Matter and Its States

• Matter has definite mass and occupies volume.

• The three states of matter are solid, liquid, and gas.

  • Solid: Definite mass and shape.

  • Liquid: Definite mass, takes the shape of its container.

  • Gas (or Vapor): Definite mass, takes the shape of its container.

• Plasma state: Ionized gas, considered the fourth state of matter.

Composition of Matter

• Matter is composed of pure substances (elements, compounds) or mixtures.

• Mixtures:

  • Homogeneous: One phase, such as solutions.

  • Heterogeneous: More than one phase (e.g., liquid and solid).

• Air is an example of a mixture.

Atomic Structure

• Nucleus: Contains protons (positively charged, mass) and neutrons (electrically neutral, mass).

• Orbits: Distinct energy levels containing electrons (negatively charged, very small mass).

Octet Rule

• Atoms tend to fill their outer shells with the required number of electrons to achieve a closed shell configuration.

• This can be achieved by adding or removing electrons.

• Cations: Positively charged ions formed by removing electrons (e.g., Na \rightarrow Na^{+1} + e^{-1}).

• Anions: Negatively charged ions formed by adding electrons (e.g., Cl + e^{-} \rightarrow Cl^{-1}).

Common Elemental Symbols

• H - Hydrogen

• C - Carbon

• O - Oxygen

• N - Nitrogen

• S - Sulfur

• P - Phosphorus

Elements

• Total number of elements: 118

• Naturally occurring elements: 92

• Man-made (synthetic) elements: 26

Periodic Table

• Polar Covalent Bonds: Uneven distribution of electrons around the molecule, leading to a dipole moment.

• Non-polar Covalent Bonds: Even distribution of electrons around the molecule.

Non-Bonding Associations

• Hydrogen Bonding: Attraction between hydrogen and electronegative elements (O, P, N), contributing to high boiling points.

• Dipole-Dipole Interactions: Attraction between the positive pole of one molecule and the negative pole of another. Stronger than Van der Waals.

• Van der Waals Forces: Weak, temporary dipole-dipole attractions arising from instantaneous dipoles in atoms. Important in ideal gases.

  • Ideal gas atoms should neither attract nor repel one another.

  • Real gas atoms have instantaneous dipoles.

  • Partial charges on one atom distort neighboring atoms due to electrostatic interactions.

  • Attractions between opposite partial charges cause atoms to "stick together" for a short time.

Water

• Essential for living organisms.

• Boiling Point (BP) = 100°C

• Melting Point (MP) = 0°C

• Density of liquid water = 1 gram/cc

• Frozen water (ice) is less dense than liquid water.

• Bent geometry contributes to its polarity.

• High Heat of Vaporization

• Good Solvent

• Cohesive Forces

• Adhesive Forces

• High Surface Tension

Periodic Table History and Properties

• First created by Dmitri Mendeleev, arranged by atomic weight, later revised by atomic number.

• Element properties relate to its atomic number (number of protons).

• Atomic mass is the sum of protons and neutrons in the nucleus.

• Isotopes: Forms of an element with differing atomic masses due to variations in neutron number.

• Half-life: Time for half the mass of a radioactive isotope to decay.

Radioactive Emissions

• Alpha particles: Helium nuclei (He^{+2}).

• Beta particles: High energy electrons.

• Gamma particles: High frequency light rays.

Atomic Weights

• Atomic weights are weighted averages based on the %abundance of isotopes.

• Formula: (% \text{ abundance of isotope 1} \times \text{mass of isotope 1}) + (% \text{ abundance of isotope 2} \times \text{mass of isotope 2}) + …

Electromagnetic Spectrum

• From low frequency/low energy to high frequency/high energy: Radiowaves, microwaves, infrared rays, visible light, ultraviolet rays, x-rays, gamma-rays.

Chemical Bonding

• Molecules: Formed by covalent bonding (sharing of electrons).

• Ionic compounds: Formed by electrostatic attraction between positively and negatively charged ions.

Properties of Molecules

• Boiling point

• Melting point

• Density (mass/volume)

• Shape of molecule

• Solubility

Buffers

• Chemicals that resist changes in pH within limits (buffering capacity).

• In humans, carbonic acid acts as a buffer to neutralize added hydrogen or hydroxide ions due to metabolic instability.

Life's Functions

• Growth

• Nutrient gathering (nutrition)

• Reproduction

• Eating

• Excretion

• Transport

• Regulation

Homeostasis

• Regulation of an organism's internal environment despite changing external conditions.

Classification Scheme

• Domain

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

• Example: Homo sapiens (classification for humans)

Scientific Method

• Observe: Use senses for identification.

• Make a Hypothesis: Educated guess.

• Design an Experiment:

  • Control: Contains everything except the variable of interest.

  • Experimental: Contains everything.

• Collect Data, Analyze Results: Avoid bias.

• Discuss Results: Draw a conclusion.

• Determine if the hypothesis was accepted or rejected.

Living Cells

• Definition: Capable of reproducing itself without external help.

• Viruses and prions are not considered living cells.

Cell Types

• Eukaryotes: Contain a true nucleus.

• Prokaryotes

Water and Its Properties

• Density of liquid water = 1 gram/cc

• Frozen water is less dense than liquid water

• Bent geometry

• Polar molecule

• High Heat of Vaporization

• Good solvent

• Cohesive forces

• Adhesive forces

• High surface tension

Water Importance in Humans

• Sweat/perspiration

• Thirst

• Digestion

• Excretion

• Blood

• Dehydration

• Water Toxicity

Water Composition of the Human Body

• Overall: 72% water

• Lungs: 90% water

• Blood: 82% water

• Skin: 80% water

• Muscle: 75% water

• Brain: 70% water

• Bones: 22% water

Acids and Bases

• Acids: Release hydrogen ions into solution.

• Bases: Release hydroxide ions into solution.

Acidity Measurement

• Measured by pH.

• pH scale: Ranges from 0 to 14, with 7 being neutral.