Chapter 2 Biology study guide

Given a pH of a particular solution, determine if that solution is acidic, basic, or neutral.

1-7 acidic 7-14 basic 7 neutral

Use the periodic table to determine an atom's atomic number, atomic mass, and number of electrons, and describe the relationship between atomic number and atomic mass.

Atomic number = number of protons in nucleus. Atomic mass number = number of all particles in nucleus = protons + neutrons.

8. Compare and contrast ionic and covalent bonds.

Covalent bonds are the strongest kind in which two atoms share one or more pairs of outer-shell electrons. Iconic bond is an attraction between ions of opposite charge. one atom tranfers an electron to another. Transfer of an electron from one atom to another results in a positive ion (cation) and a negative ion (anion)

Describe and recognize examples of the properties of water created by the formation of hydrogen bonds between water molecules

Large numbers of water molecules orient themselves so that the negative side of one molecule is near the positive side of another. Hydrogen bonds form between the relatively positively charged hydrogen atoms and the relatively negatively charged oxygen atoms of adjacent water molecules. properties of water: 1. Cohesion: Water molecules bind to each other due to hydrogen bonding. Water molecules can pull up adjacent water molecules to which they have hydrogen-bonded. 2. Large heat capacity: because water resists warming, it takes a lot of energy to change the temperature of water even a small amount. When we heat water, the added energy doesn't immediately increase the movement of the individual water molecules. Rather, it disrupts some of the hydrogen bonds between the molecules. The hydrogen bonds form again somewhere else, and since the water molecules themselves don't increase their movement, the temperature doesn't increase. 3. Low density as a solid: As the cooling molecules slow down, they pack together more and more efficiently-and densely. Water, however, becomes less dense, this unusual property is due to hydrogen bonding. As the temperature drops and water molecules slow down, each V-shaped water molecule bonds with four partners, via hydrogen bonds, forming a crystalline lattice in which the molecules are held slightly farther apart than in the liquid, causing ice to be less dense than water. 4. Good solvent: If you put a pinch of table salt into a glass of water, it will quickly dissolve. This means that all the charged sodium (Na+) and chloride (Cl-) ions that were ionically bonded together become separated from one another. The sodium and chloride ions were initially attracted to each other because they carry a slight opposing charge. Water is able to pry them apart because, as a polar molecule, it, too carries charges. The positively charged sodium ions are attracted to the negatively charged side of the water molecules, and the negatively charged chloride ions are attracted to the positively charged side. The ionic bonds holding together the ions are broken, and each ion becomes surrounded by water molecules. Water pries apart ionic bonds, dissolving ionic compounds.

Given appropriate information, draw examples of atoms using the electron shell model

Nitrogen: 7 nuetrons,7 protons, 7 electrons

10. Determine the types of bonds formed in molecules such as: a) O2 b) NaCl c) CH4 d) H2O

O2: A double covalent bond is where two pairs of electrons are shared between the atoms rather than just one pair. Two oxygen atoms can both achieve stable structures by sharing two pairs of electrons as in the diagram. NACl: The type of bonding found in sodium chloride is called ionic bonding. Ionic bonding is the attraction between two atoms with opposite charges. In sodium chloride, sodium has a positive charge and chlorine has a negative charge; therefore, they attract one another and form a bond. CH4: molecule exhibits single covalent bonds. Covalent bonding involves the sharing of electrons. In the methane molecule, the four hydrogen atom share one electron each with the carbon atom. H2O: H2O, is comprised of covalent bonds. These incredibly strong bonds hold the hydrogen and oxygen molecules together. Water molecules are polar molecules, which maintain a bent shape.

5. Define and differentiate between an atom, a molecule, ion, isotope, and radioactive isotope.

The difference between atoms, ions and isotopes is the number of subatomic particles. atom- is the smallest molecule of an element molecule- a group of atoms bonded together ions- the number of electrons differs, positively and negatively charged atoms isotopes- the number of neutrons varies radioactive isotopes- is one in which the nucleus decays spontaneously, giving off particles, and energy.

Describe the relationship between hydrogen ion concentration, hydroxide ion concentration, and pH

The term pH followed by a number indicates a solution's relative hydrogen ion concentration compared to hydroxide concentration (Thibodeau, pg. 588). The overall pH range is expressed on a logarithmic scale of 1 to 14. A change of 1 pH unit represents a tenfold difference in the concentration of hydrogen ions in a solution. As the concentration of H+ ions increases, the solution becomes increasingly acidic and the pH decreases. If OH- concentration increases, the pH value also increases and the solution becomes more alkaline. A pH of 7 is neutral; a pH of 1 is very acidic, and a pH of 13 is very alkaline (Thibodeau, pg. 588).

Differentiate between an atom and an element

atom: A fundamental building block containing a nucleus and surrounding electron shells. Inside the nucleus there are Neutrons and Protons. Orbiting the nucleus are Electrons. element: Substances made up of only one atom there are 118

Define and interrelate the following terms: chemical reaction, reactants, products, and conservation of matter.*

chemical reaction: making and breaking chemical bonds -chemical reactions may change the composition of matter reactants interact -> leading to products the number of atoms stays constant on both sides of the equation.. due to the conservation of matter matter is anything that occupies space and has a mass and is either a solid, liquid or gas

9. Define and interrelate the following terms: electronegativity, polar covalent bond, ion, nonpolar covalent bond, and ionic bond.

electronegativity nonpolar covalent bond: occur when electrons are shared equally between atoms. polar covalent bond: the pulling of shared, negatively charged electrons closer to the more electronegative stom makes that atom partially negative and the other atom partially positive.

Define and interrelate the following terms: acid, base, pH scale, and buffer

pH: The measure of a solutions' potential to attract Hydrogen ions. The measure of how acidic or basic a solution is. Acid: A solution that has a higher concentration of hydrogen ions (H+) than hydroxide ions (OH-). A proton (H+) donor. Base: A solution that has a higher concentration of hydroxide ions (OH-) than hydrogen ions (H+). A proton (H+) acceptor. Buffer: solutions that can resist changes in pH, are key to maintaining stable H^+ biological conesntration. Buffers typically consist of an acid-base pair, with the acid and base differing by the presence or absence of a proton (a conjugate acid-base pair).

Define and interrelate the terms solute, solvent, and solution

solute: the substance dissolved in a solution solvent: the liquid in which a solute is dissolved to form a solution solution: a solute dissolved in a solvent solute+solvent=solution