Chemistry Flashcards
The equilibrium constant of a chemical reaction…
is the value of the reaction quotient when the reaction has reached equilibrium.
An equilibrium constant value is independent of the…
concentrations of the reactant and product species in a mixture.
An equilibrium constant value depends on…
temperature and ionic strength.
Known equilibrium constant values can determine…
the composition of a system at equilibrium.
Define the equilibrium constant (K) for the following reaction aA + bB -> cC + dD
K = (C^c * D^d)/(A^a * B^b)
Define pH
It is roughly the negative of the logarithm to base 10 of the concentration, measured in units of moles per liter, of hydrogen ions or H+.
An object is chiral if
it can be distinguished from its mirror image.
Is there a greater change in free energy, between reactants and products, in the presence of a catalyst?
No.
Peptides are…
biologically occurring short chains of amino acid monomers linked by peptide (amide) bonds.
Amino acids are…
biologically important organic compounds containing amine (-NH2) and carboxylic acid (COOH) functional groups, usually along with a side chain specific to each amino acid.
In biochemistry, which group of amino acids are particularly important?
Those where the amine and carboxylic acid groups are attached to the first alpha carbon atom. These are known as alpha amino acids.
The generic formula of an alpha amino acid is
H2NCHRCOOH
where R is an organic substituent known as a side chain.
A peptide bond
is a covalent chemical bond formed between two amino acid molecules. Also known as an amide bond.
In biochemistry, a condensation is when…
two amino acids form a dipeptide through a peptide bond.
What does each amino acid lose during condensation?
One loses a hydrogen and oxygen molecule from its carboxyl group and the other loses a hydrogen from its amino group. Thus, a molecule of water is produced.
General formula of a peptide bond
-CO-NH-
If a non-volatile and unreactive solute is added to a solvent, the vapour pressure…
above the resulting solution is less than the vapour pressure above the pure solvent. This is Raoult’s Law.
The pressure exhibited by a vapour present above a liquid suface…
is known as vapour pressure.
The vapour pressure above a solution is equal to…
the vapour pressure of each component multiplied by its mole fraction (molar proportion). Raoult’s Law.
A hydroxyl is a…
chemical functional group containing one oxygen atom connected by a covalent bond to one hydrogen atom.
A covalent bond is a…
chemical bond that involves the sharing of electron pairs between atoms.
Hydroxyl is sometimes called the
alcohol functional group.
IUPAC stands for
International Union of Pure and Applied Chemistry
How does IUPAC distinguish between the terms hydroxyl and hydroxy
the term hydroxyl refers to the radical OH only, while the functional group -OH is called the hydroxy group.
A hydroxyl group bonded covalently to the carbon of a carbonyl group produces…
a carboxyl group.
(C(O)OH).
This is the defining group of carboxylic acid.
beta-hydroxyacids is a colloquial term for
organic acids that have a hydroxy group and on the second carbon from the carboxylic acid group.
Mevalonic acid is a precurser to…
the production of cholesterol in the body.
Drugs such as statins lower the cholesterol…
by stopping the production of mevalonate by inhibiting HMG-CoA reductase.
What is peculiar about carbon’s outer shell?
To obatin an outer shell, carbon must gain or lose four electrons a energetically impossible state under normal conditions. Therefor, carbon bonds covalently in all its elemental forms and compounds.
To catenate is
to bond to oneself.
Being a small atom carbon forms…
relatively short, storng bonds.
A functional group is…
a specific combination of bonded atoms that reacts in a characteristic way no matter in which molecule it occurs.
Monosaccharides are…
the most basic units of carbonhydrates. They can not be further hydrolised in to simpler compounds. They include, glucose (dextrose), fructose and galactose.
A racemic mixture…
or racemate is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule. A racemate is optically inactive, meaning that there is no net rotation of plane-polarized light.
An enantiomer,
is one of two stereoisomers that are mirror images of each other that are non-superposable (not identical), much as one’s left and right hands are the same except for being reversed along one axis (the hands cannot be made to appear identical simply by reorientation).
A dimer is…
an oligomer, consisting of two structurally similar monomers.
A homodimer is sometimes used when they are identical.
hydrolysis
generally means the cleavage of chemical bonds by the addition of water.
Allotrope
Different structural modifications of an element. For example, diamond and graphite are different structures of carbon.
Aryl group
any aromatic ring
A drop in oxidation number =
a gain in electrons
=
reduction
=
this species is the reduction agent.
FeCl2(aq) + H2S(g) –> FeS(s) + 2HCl(aq)
What type of reaction is this?
Double replacement.
What change must occur in an oxidation and reduction equation?
Elements must change their oxidation numbers.
Which element has the electron configuration 1s2 and what is peculiar about it?
Helium. Helium is in the S block, however is also a noble gas (Group VII).
