Molecules and Bonds Flashcards
What are the subatomic particles?
Protons, neutrons, and electrons
What is atomic mass?
Protons and neutrons in the nucleus
What is atomic number?
Number of protons in the nucleus
What is an isotope?
An atom with a different ratio of protons and neutrons
What determines the type of bond an atom can form?
electronegativity, or the amount of pull it has for its electrons
What are the electronegativity values?
0.0-0.4 = nonpolar covalent
0.4-2.0 = polar covalent
2.0-4.0 = ionic bond
What is nonpolar covalent bond?
electrons shared equally
What is polar covalent bond?
electrons shared unequally, can lead to partial negative and partial positive
What is ionic bond?
electrons transferred
What are some weak bonds?
ionic bonds, hydrogen bonds, van der Waals (induced dipole within 5 nm)
Why do we want weak interactions?
Cells need reversible reactions for cellular processes
What are important properties of water?
- Cohesion
- High heat capacity
- Its less dense as a solid than liquid
- It dissolves polar molecules
- It surrounds non-polar molecules
What are molecules that have both hydrophobic and hydrophilic properties?
Amphipathic molecules.
What happens when you mix oils in water?
Water forms a cage around hydrophobic molecule. This is not energetically favorable
What is an amphipathic material in the cell?
Phospholipids which are found in membranes.
What is autohydration?
At very low frequencies, water can transfer its hydrogen atom to another. Making hydronium (H3O+) and hydroxide (OH-)
What does pH measure? What is high vs low?
pH measures hydronium (H3O+) ions or [H+].
Low pH = more [H+]
High pH = less [H+], more [OH-]
What is the range of pH?
0 pH is very acidic
7 pH is neutral
14 pH is very basic
Is urine acidic or basic?
acidic
What is a buffer?
chemicals in solutions that minimize change in pH when acids or bases are added
