chapter 2 chemical properties Flashcards
the smallest chemical unit of matter
atom
define what atom mean
the smallest chemical unit of matter
define what element is
matter composed of one type of atom
matter composed of one type of atom and name some examples
element
ex: carbon, nitrogen, oxygen, sodium
two or more atoms combine to form
a molecule
different two or more atoms combine
compound
what charge does protons have?
positive charge
what charge does neutrons have ?
neutral charge
true or false, every atom as a centrally located nucleus but does not contain a net positive charge?
false, it does contain a centrally located nucleus however it also contains a net positive charge
__ and is stable and does not participate in chemical reactions.
Nucleus
name 3 characteristics of electrons
1)circle the nucleus and are negatively charged
2)stabilize the positive charge of the nucleus
3)an equal number of electrons and protons will give a net charge equal to neutral
Unlike protons and neutrons, which are densely packed in the nucleus, the lighter _____ orbit the nucleus in shells.
Electrons
True or false. Electron shells correspond to different energy levels
True
How do chemical bonds form between atoms ?
through interactions of electrons in their outer shells
How do every atoms become chemically stable, and how do you achieve this?
by filling its outermost shell with electrons
how do atoms achieve a full complement of electrons?
by combining together to form molecules
if an atom lose an electron it has an overall what charge?
positive
if an atom gains an electron it has an overall
negative
define what an ion is
an atom (or group pf atoms) that has a positive or negative charge is an ion
defined what an cation is
loss of an electron
define what an anion is
gained of an electron
name the 3 kinds of chemical bonds found in living organisms
1) ionic
2)covalent
3)HYDROGEN BONDS
result from attraction between ions of opposite charges
ionic bonds
what forms ionic bonds to neutralize their changes
anion and cation
attraction holds the ions together to form a ______
compound
this type of bond form when atoms share pairs of electrons
covalent bonds
this type of bond is found in many compounds, especially those that contain carbon
covalent bond
true or false. Covalent bonds are not very strong bonds, ionic are stronger
false, they are a very strong bonds
True or false, carbon atoms can form up to 4 covalent bonds
True
define what hydrogen bonds are
occur between covalently bonded molecules that display polarity
Name the example: When hydrogens are bonded to oxygen, the larger oxygen atom tends to pull the electrons closer to itself
hydrogen bonds
True or false. Hydrogen bonds creates a region with partial negative charge (O) and a region with partial positive charge (H).
True
name some more characteristics of hydrogen bonds
1)loose attraction between oppositely charged regions of different molecules
2) weaker than ionic and covalent bonds
3)serve to bridge separate molecules together
Approx. how much percentage if the cell weight of water
75%
Define the charge distribution of water.
Water has an unequal charge distribution
True or false.
Each water molecule can form up to four hydrogen bonds with other molecules, in which gives its unique properties
True
Water as the solvent of life (point #3 and #4)
makes water resist rapid changes in temperature and imparts a high boiling point (100).
is water a polar solvent?
yes
water as the solvent of life, unequal charge distribution allows it to dissolve many covalent compounds
False, unequal charge distribution allows it to dissolve many ionic compounds
Water as the solvent of life:
positive regions of water molecules surround negative ions and negative regions surround positive ions
True or false
True
water as the solvent of life holds the ions in solution
Yes, it does hold the ions in solution
Polar nature of water and gives it following characteristics
- High boiling point, strong attraction between water molecules
2.due to polarity: many polar substances undergo dissociation (they dissolve positive portion of solute molecule attracted to neg. O, and negative portion of solute attracted to positive H.
therefore, salt like nacl tends to separate into cations and anions.
Name the other 2 characteristics of polar nature.
3.water is key for digestive processes: large molecules broken down into smaller.
also for synthetic reactions: important source of H and O atoms that are incorporated into numerous organic compounds in living cells.
4.heat absorption by molecules tends to increase kinetic energy and their rate of motion. With water, heat first results in breaking H-bonds rather than increasing rate of motion.
True or false.
water’s polarity facilitates the splitting and joining of hydrogen ions (H+) and hydroxide ions (OH-).
Making these ions unavailable for chemical reactions.
True
What does pH scale describes as a concentration
pH scale describes the concentration of H+ ions in a solution.
measure of acidity: and gives it description
pH 7=
pH below 7=
pH above 7=
pH 7= neutral (pure water)
pH below 7= acidic
pH above 7= basic or alkaline
organic molecules, is any molecule that contains both what?
carbon and hydrogen
True or false.
Because each C atom can participate in 4 covalent bonds, carbon can be used to build an enormous variety of compounds.
true
What are the four major classes of organic molecules that make up the building blocks of life
1) carbohydrates
2) lipids
3) proteins
4)nucleic acids
large group of compounds including sugars and starches
carbohydrates and all contain the elements of CHO , and they are generally polar and ready source of energy for cells.
types of carbohydrates
1)monosaccharides
2)disaccharides
3)polysaccharides
polysaccharide are often soluble in water?
no, it is not usually soluble
What does lipids include?
lipid includes fats, complex lipids(phospholipids) and steroids and is essential to the structure and function of membranes
lipids is used for something else, and not energy storage
false, it is used for energy storage
what does hydrophobic mean?
water hating
Define this :
Made from glycerol backbone +1 or more fatty acids.
Fats
monoglycerides
1 fatty acid
diacyglycerides
2 fatty acids
triacyglycerides
3 fatty acids
fatty acids can be saturated or unsaturated. What does that mean?
saturated means no double bonds and unsaturated mean double bonds
complex lipids such as phospholipids contain what
glycerol,2 fatty acids, and a phosphate group.
the phosphate group is polar which means what?
hydrophilic
The fatty acid tails are non-polar which means what?
Hydrophobic
saturated fatty acids tend to form membranes that are more…..
solid
unsaturated fatty acids tend to be more…..
fluid
biological membranes , what a re they made from and what are they? and name a characteristic
are made from phospholipids bilayers
are semi-fluid(contain a mix of saturated and unsaturated fatty acids)
separate the watery inside of the cell from the watery environment.
what is another type of lipids?
steroids
what is structurally different from other lipids?
steroids
built, on a hydrophobic 4 ring structure, generally found in eukaryotes and not prokaryotes, example are cholesterol and ergosterol and vitamin d.
steroids(sterols)
what are the building blocks of proteins?
amino acids
proteins all contain what…?
C H O N and some have S
required in all aspects of cell structure and function, some are structural, and most act as enzymes in which increase the rate at which chemical reactions take place in living organisms.
proteins
proteins typically contain how many amino acids
20 different amino acids
true or false. proteins typically have at least one amino (-NH2) and one carboxyl (-COOH) group.
true
proteins typically contain side groups which determines what ?
properties
amino acids are joined to make proteins by
covalent peptide bonds
What is a polypeptide
it is a protein chain of amino acids
___ and ___ of the protein is determined by the sequence of amino acids.
shape and function
what does dna and rna stand for?
deoxyribonucleic acid
ribonucleic acid
nucleic acids built of building blocks is called
nucleotides
what are the 3 parts of nucleic acids?
nitrogenous base
pentose sugar
phosphate
name the nitrogenous bases
purine= 2 ring =adenine or guanine
pyrimidine=1 thymine and cytosine and uracil
how many sugar does pentose habe?
5 sugars
ribose,deoxyribose
what are joined together by covalent bonds to form a strand of nucleic acids?
nucelotides
name the characteristics of dna
double stranded
nitrogenous base: A,T,C,G
stores genetic info of all cellular organisms
name the characteristics of rna
A, G, U , and C
sugar ribose
single stranded
involved in communicating and instructions stored in DNA
dna structure:
each strand is built from a
sugar phosphate backbone
dna structure:
two strands are held together by what
and what do they form?
hydrogen bonds in between nitrogenous bases
they form double helix
name the base pairing in rna and dna
a t
c g in dna
a u
cg in rna
Proteins acts as enzymes which decreases the rate at which chemical reactions take place in living organisms?
false. they increase the rate at which chemical reactions take place in living organisms.
