Chapter 2-4: Chemistry Flashcards
What does it mean if two atoms have equal electronegativity?
They share electrons evenly
What does it mean if two atoms have unequal electronegativity?
They share electrons unevenly
What does it mean if two electrons have extremely unequal electronegativity?
They do not share electrons at all
Ionic bonds form between __________.
A metal and a nonmetal
Eg, Na and Cl form an ionic bond as Ana donates an electron to Cl.
Why do ionic bonds form?
When there is extremely unequal electronegativity.
After the electron has transferred, the positive cation (Na) attracts the anion (Cl).
Covalent bonds form between ________.
Two nonmetals
Equal electronegative sharing = ______ covalent bond.
Unequal electronegative sharing = ________ covalent bond.
Nonpolar
Polar
Is methane polar or nonpolar?
Nonpolar because of equal sharing
H
|
H - C - H
|
H
No electrons left over
Is H2O (water) polar or nonpolar?
Polar because of unequal sharing .. \: O - H | H
Oxygen has extra electrons leftover
If a compound has:
N, O, F
And H, C
it is ________.
Polar
Eg, H2O
If a compound has either:
N, O, F
Or H, C
it is ________.
Nonpolar
Eg, CH4
What are the 3 hydrogen bond requirements?
- H atom covalently bonded to N, O, F on first molecule
- H atom covalently bonded to N, O, F on second molecule
- The partial S+ of a H atom is attracted to partial S- of N, O, F atom
Eg, water with water, NH3 with HF, not CH4 with water
What are emergent properties?
Properties that the original complex does not have, but gains as it advances.
What are the 4 emergent properties of water?
- Cohesion and Adhesion
- Cohesion: water attracted to water
- Adhesion: water attracted to other molecules
- Moderation of Temperature
- Water has a high specific heat
- Ice is less dense that water
- Ice has more hydrogen bonds, meaning it has more air, that’s why it floats
- In water, hydrogen bonds are constantly breaking and reforming, therefore it is heavier and liquidy
- Water is a good solvent
- This is because water is polar, its partial charges interact with other molecules (such as Na and Cl)
If something is hydrophilic, what does it mean?
- Water loving
- Polar
- Ionic compounds
If something is hydrophobic what does it mean?
- Water fearing
- Nonpolar
- Nonionic compounds
What does an acid do? What is the concentration of H+ in comparison to the concentration of OH-?
Increases H+ concentration in a solution
(“Donates H+”)
[H+] > [OH-]
What does a base do? What is the concentration of H+ in comparison to the concentration of OH-?
Reduces the H+ concentration in a solution
(“Accepts H+”)
[H+] < [OH-]
pH = ?
-log[H+]
Compared to an acidic solution at pH 5, a basic solution at pH 8 has
A. 3 times more hydrogen ions
B. 3 times fewer hydrogen ions
C. 1,000 times more hydrogen ions
D. 1,000 times fewer hydrogen ions
D.
Step 1
• 8 - 5 = 3
• 10^3 = 1,000
Step 2
• pH 8 is basic, meaning it has fewer H+ ions
When there’s a high pH and low H+ concentration, the solution is ______.
Basic
When there’s a low pH and high H+ concentration, the solution is ______.
Acidic
Which functional group is this? What are its characteristics?
- OH
Alcohol/Hydroxyl
- Polar / Hydrophilic
- H-Bonding
O is S- and H is S+
Which functional group is this? What are its characteristics?
O
||
- C -
Carbonyl
- Polar / Hydrophilic
- H-Bonding
O is S- and C is S+
Which functional group is this? What are its characteristics?
- COOHO
|| - C - OH
Carboxylic acid
(Combo of hydroxyl and carbonyl)
- Polar / Hydrophilic
- H-Bonding
Which functional group is this? What are its characteristics?
- NH2
H
/
- N
\
H
Amino
- Polar / Hydrophilic
- H-Bonding
N is S- and H is S+
Which functional group is this? What are its characteristics?
- SH
Sulfhydryl
- Somewhat Polar
Which functional group is this? What are its characteristics?
- OPO3^2-
O
||
- O - P - O
|
O
Phosphate
- Polar / Hydrophilic
- Ionic bonding
Which functional group is this? What are its characteristics?
- CH3
H | - C - H | H
Methyl
- Nonpolar / Hydrophobic
