Chapter 2 Flashcards
What is energy?
The ability to do work, move matter
What is matter?
Any material that takes up space
Name 4 major elements.
Hydrogen
Oxygen
Nitrogen
Carbon
Name the 4 parts of an elements box on the periodic table.
Atomic number
Element name
Element symbol
Atomic mass
What is an atom made up of? And where are each located?
Protons- nucleus
Neutrons- nucleus
Electrons- surrounds nucleus
What is the charge and mass of the 3 particles an atom is made up of?
Proton-pos (+) charge, mass of 1
Neutron- neutral charge, mass of 1
Electron- neg (-) charge, mass of 0
What is an ion?
An atom (or group of atoms) that have gained or lost an electrons, giving it an electrical charge
What is the atomic number represent?
The number of protons in an atom.
What is the mass number?
The total number of protons and neutrons in its nucleus.
Explain an isotope.
When the number of neutrons varies among atoms of the same element. (Each isotope therefore has a dif mass number)
What is the atomic weight?
Average mass (weight) of all isotopes
How do you determine the number of neutrons in an element?
Subtract the atomic number from the atomic mass
(P+N)-P= N
What is an element?
A fundamental type of substance
What’s an atom?
Smallest unit of an element that retains the characteristics of that element.
What is a molecule?
Two or more chemically joined atoms
What is a compound?
Molecules made up of two or more different elements. Exp: H2O
What are energy shells? And how many electrons does each one hold?
Orbitals carrying electrons on the same level.
The lowest energy shell holds 2 electrons, the next shells can hold up to 8.
When are Atoms most stable? And how does that occur?
They are most stable when their valence shell is full. It occurs with chemical bonds.
What is a valence shell?
Outermost occupied energy shell.
Name three chemical bonds.
Covalent, ionic, and hydrogen
Explain covalent bonds.
When 2 Atoms share pairs of electrons to fill their valence shells.
What are the two types of covalent bonds?
A nonpolar (equal) covalent bond is when both atoms exert approximately equal pull on their shared electrons. A polar (unequal) covalent bond is when one nucleus exerts stronger pull on the shared electron.
What is electronegativity?
The measure of an atom’s ability to attract electrons.
In the molecule H2O, describe which Atom has slightly negative charge and which atom has slightly positive charge and why?
H (2.2)
O (3.4)
The two hydrogen atoms are slightly positive (+) and the oxygen atom is slightly negative (-) because of the electronegativity difference. Oxygen has stronger pull.
What happens in an ionic bond?
When one atom transfers electrons to another Atom because of the electrical attraction between two ions with opposite charges.
An Atom that loses an electron is…
An atom that gains an electron is…
Positively charged Negatively charged (Ions)
If Na has 11 electrons, that leaves 1 in the valence shell. Cl has 17, leaving 7 in valence shell. Explain the bond that can occur and why.
An ionic bond will occur because the one electron in sodium will be donated to the chlorine atom to fill its valence shell making them both stable. This creates ions sodium (+) chloride (-) also known as table salt.
What is a hydrogen bond?
Weak chemical bond between opposite partial charges onto molecules or within one large molecule.
H20 to H20
What is a chemical reaction?
When Two or more molecules swap their atoms to yield different molecules.
What is the reactant?
Starting material
What is the product?
Result of reaction
Exp:
CH4 + 2O2 —-> CO2 + 2H2O
methane + oxygen –> carbon dioxide+ water
What are five properties of water?
Cohesion
Solvent
Evaporating (regulates temps)
Freezing (stable bonds, less dense) Chemical reactions (reactant or product of many)
What is cohesion?
The tendency of water molecules to stick together
How do water molecules stick together?
Hydrogen bonds
What is a solvent?
Chemical in which other substances dissolve
What is a solute?
Dissolved substances
What is a solution?
One or more solutes dissolved in a liquid solvent
Scientist divide chemicals into two categories based on solubility in water. What are they? Explain.
Hydrophilic-Substances are either polar or charged so they are readily dissolved in water (water loving).
Hydrophobic-nonpolar molecules made mostly of carbon and hydrogen, they do not dissolve, or form bonds, in water (water fearing).
The polarity (+,-) of water molecules helps water dissolve ____.
Ions
What is evaporation?
The conversion of liquid into vapor
The pH scale is based on The amount of _____ in a solution.
H+
Acidic solutions have a ____ pH and a ____ H+ concentration.
Low
High
Basic solutions have a ____ pH and a ____ H+ concentration.
High
Low
Bases have more ____ ions than ____ ions.
OH-
H+
PH scale range is ____.
1-14
Neutral on the pH scale is considered ____.
7
What is a buffer system?
Pairs of weak acids and bases that resist pH changes.
Solution that consumes or releases H+ to maintain constant pH.
What is pH for?
Scale that measures how are acidic or basic a solution is, & measurement of # H+ ions
What does neutral represent on the pH scale?
Same amount of H+ as OH-
What is an acid?
Molecules that release H+ when dissolved in H2O
What is a base?
Substance that removes H+ from solution
What are the four main types of organic molecules?
Proteins lipids carbohydrates and nucleic acids
What two elements do organic molecules contain?
Carbon and hydrogen
What is a monomer?
Single unit of a carbohydrate protein or nucleic acid
What is a polymer?
Joined monomers
What is dehydration synthesis?
An enzyme binding to monomers releasing a water molecule (h2o)
What is hydrolysis?
The reverse reaction of dehydration synthesis. Water (h2o) is used to break polymers into monomers.
What are the monomers and polymers of carbs?
Monosaccharides and polysaccharides
What are the most common polysaccharides? (4) and their function.
Cellulose-plant structure
Starch-Storage molecules (plants)
Glycogen- storage molecules (animal/fungal)
Chitin-cell wall (insects/fungi)
Lipids are not built from chains of monomers, true or false?
TRUE
What are two groups of lipids?
Triglycerides and sterols
What does a triglyceride contain?
Glycerol link to three fatty acid’s
What is glycerol?
A three carbon molecule that forms the triglycerides backbone
What are fatty acids?
Three long hydrocarbon chains with a carboxyl group at the top (c=o)
Name the two types of fatty acid. Explain their differences.
Saturated, “saturated with hydrogen” and is solid at room temperature the chains are straight.
Unsaturated, kinked chains
What are sterols?
Lipids that have for interconnected carbon rings. Example cholesterol.
What is the monomer and polymer of protein?
Amino acids and proteins
What is the general structure of amino acids?
Central Carbon Atom, linked with an amino group, carboxyl group, and R group (variable).
How are dipeptide, tripeptide and polypeptides formed?
Dehydration synthesis, linking two, three, and more (long chains) of amino acids.
What is a peptide bond?
Covalent bond that links each amino acid to its neighbor
What are the four levels of protein structure? And explain.
Primary (1): linear amino acid sequence of the polypeptide chain
Secondary (2): The first folding of amino acids into coils cheats and loops resulting from hydrogen bonds between parts of the polypeptide.
Tertiary (3): overall shape of a polypeptide, interacting with the R group, enzymes,more folding,hydrogen bonds, covalent bonds.
Quaternary (4): overall protein shape arising from the interactions between multiple polypeptide subunits of the same protein.
What is Denatured?
If it’s structure is modified enough to destroy its function. Examples heat, excessive salt, and wrong pH can destroy the hydrogen bonds that maintain second and tertiary structure
What are the monomers and polymers of nucleic acid?
Five nucleotides
And nucleic acids
What are the two types of nucleic acid’s?
DNA and RNA
What are the three basic components of nucleotides?
Five carbon sugar (2), nitrogenous base (5), and a phosphate group
What are the two types of five carbon sugar’s?
Deoxyribose (DNA) ribose (RNA)
What are the five types of nitrogenous bases? And which sugar uses each?
(Both DNA/RNA): Adenine cytosine guanine
(DNA): thymine
(RNA): uracil
