Chemistry Solutions and Properties Quiz

Atomic Structure

• Matter is a substance with mass and occupies space
• Matter exists in three forms: solid, liquid, and gas
• All matter is composed of atoms
• Atoms are the smallest particles exhibiting element's chemical properties
• There are 92 naturally occurring elements
• Elements are organized in the periodic table
• Elements are categorized as major, minor, or trace elements based on their percentage in the human body
• Major elements comprise almost 99% of the body's weight
• Minor elements comprise less than 1% of the body's weight
• Only 12 elements occur in living organisms in larger quantities
• Atoms are composed of protons, neutrons, and electrons
• Protons have a positive charge and a mass of 1 amu
• Neutrons have no charge and a mass of 1 amu
• Electrons have a negative charge and a mass of 1/800th the mass of a proton or neutron
• Protons and neutrons are located in the atomic nucleus
• Electrons are located in orbitals or shells around the nucleus
• Each shell (orbital) has a limited capacity for electrons
• Electrons fill the innermost shells first
• Atoms achieve stability by filling their outermost electron shell, often eight electrons
• Isotopes are atoms of the same element with the same number of protons and electrons but a different number of neutrons
• Radioisotopes are unstable isotopes that emit radiation as they decay
• The atomic number represents the number of protons in an atom
• The average atomic mass represents the mass of protons and neutrons

Ions and Ionic Compounds

• Ions are atoms or groups of atoms with a net electrical charge
• Cations are positively charged ions (formed by losing electrons)
• Anions are negatively charged ions (formed by gaining electrons)
• Polyatomic ions are groups of atoms with a net charge
• Ionic bonds are formed by electrostatic attractions between oppositely charged ions
• Salts are compounds formed from ionic bonds
• Electrolytes are substances that conduct an electric current in solution; many important ions are electrolytes

Covalent Bonding

• Covalent bonds are formed when atoms share electrons
• Molecules are groups of atoms held together by covalent bonds
• Molecular compounds are formed from covalent bonds
• Covalent bonds can be single, double, or triple
• Electronegativity is the ability of an atom to attract electrons in a covalent bond; differences in electronegativity between atoms in a bond affect its polarity
• Nonpolar covalent bonds have equal sharing of electrons
• Polar covalent bonds have unequal sharing of electrons; one end has a partial positive charge, the other a partial negative charge
• Intermolecular attractions, such as hydrogen bonds, are attractions between molecules

Molecular Structure of Water

• Water is a polar molecule (oxygen is slightly negative, hydrogen is slightly positive)
• Water molecules form hydrogen bonds with each other
• Water has high surface tension, high specific heat, and a high heat of vaporization
• Water is a universal solvent
• Substances can dissolve in water if they are polar or charged (hydrophilic)
• Substances that do not dissolve in water are nonpolar (hydrophobic)

Acidic and Basic Solutions

• Water can dissociate into hydrogen ions (H⁺) and hydroxide ions (OH⁻)
• Acids are substances that release hydrogen ions when dissolved in water
• Bases are substances that release hydroxide ions or accept hydrogen ions when dissolved in water
• The pH scale measures the concentration of hydrogen ions in a solution
• pH values below 7 are acidic
• pH values above 7 are basic
• A neutral solution has a pH of 7
• Buffers resist changes in pH

Water Mixtures

• Suspensions are mixtures where undissolved particles settle out over time.
• Colloids are mixtures where particles do not settle out, but are very small
• Solutions are homogeneous mixtures of dissolved substances
• Concentrations of solutes can be described using various units (mass/volume, percentage, etc.).

Biological Macromolecules

• Four major classes: carbohydrates, lipids, proteins, and nucleic acids
• Monomers are the building blocks of macromolecules
• Polymers are formed by linking monomers together
• Dehydration synthesis is the process of joining monomers to form polymers
• Hydrolysis is the process of breaking polymers into monomers by adding water
• Lipids are hydrophobic and function in energy storage and membrane structure
• Carbohydrates are hydrophilic and function in energy storage and structural support
• Proteins have diverse functions, including catalyzing reactions, transporting molecules, and providing structural support.
• Nucleic acids store and transmit genetic information