Intro and chemical bonds Flashcards
Equal volumes of watery solutions with same pH contain the same amount of
Protons
Rank the forces in order of strength:
hydrophobic interactions, H-bonds, covalent bonds
Covalent, H-bonds, hydrophobic
What is the mass number of an atom?
number of protons + neutron
What are isotopes and what is a main example?
Elements with same number of protons but different amount of neutrons. Mains example is carbon 14 as it allows for dating of objects (long decay period)
What are the main properties of water?
Adhesion, Cohesion, higher density as fluid, surface tension, high specific heat capacity, ice forms crytal latice, water doesn’t
What are the Van der Waals interactions?
Small attarctive forces that occur due to fluctuation of charges
What is the definition of an acid?
Releases/donates H+ ions (proton)
What is the difference between a strong and a weak acid?
A strong acid fully dissociates while a weak acid only dissocaites partially and reversibly
What is the definition of a base?
They accept H+ (realease OH-)
What is an example of an important acidic group? of a basic group?
-COOH (carboxyl) for the acid and -NH2 (amino) for the base
How does titration work?
We add a strong base into a solution with a weak acid to see the increase of pH. The pH is expected to increase dramatically btu due to the presence of the undissociated acid molecules the increase is slow. As well, adding an acid would decrease the pH slowly because the added protons would reform the undissociated form of the weak acid. Principle behind buffers
How can a buffer for both acid and base be made? Why is this the case?
If you want to make a buffer that buffers in both directions, you have to add
equal amounts of weak acid and its conjugate base to reach the half-
equivalence point of the titration curve. Becauase As can be seen
from the titration curve, a weak acid on its own can only buffer added base (and vice-verza)
What is the buffering range?
Range at which the buffer is able to effectively maintain the pH at equilibrium
Why are buffers important?
In many species, buffers can be found (like in blood) to maintaint the homeostasis of the individual
What else can you read off from a titration curve?
The protonation state,
e.g. at pH7, the COOH group discussed here will largely be COO-
Why is carbon a very important element?
It can form 4 cvalent bonds which can create an infinity of sturcutres
What are the main functional groups? What are their function?
Hydroxyl (-OH, polar, weak acid), Phospate (breaking O-P bonds releases a lot of energy), Sulfhydryle (SH, can from S-S bonds that stabilize proteins), Carbonyls( C=O, reacts with other elements), Carboxyl (COOH, acts as an acid)
What is biochemical unity and what is an advantage of it?
All biological organisms are made up of the same componentes. This is advantageous as all living organsism can feed of of one another to gain energy from digestion
What are the two main reactions in metabolism?
Condensation: release of one water molecule to add a monomer to form polymers (anabolic)
Hydrolysis: Breaking of covalent bond by addition of a water molecule (catabolic)
Chem vs Bio bond formation or breaking. Which one requires energy and which one releases energy.
Keep in mind that breaking a single covalent bond requires energy, whereas
forming a single covalent bond releases energy. When a biology textbook
talks about ATP hydrolysis releasing energy or breaking a starch polymer
into monomers releasing energy, they mean the entire chemical reaction,
which involves at least 2 covalent bonds being broken and 2 covalent bonds
being formed.
