Chapter Two: The Chemical Basis of Life Flashcards
Atom
Smallest unit of matter
What is the mass of both Neutrons and Protons?
1
What is the mass of an Electron?
Zero
What is a Neutral Atom?
The number of protons and electrons are the same
What 4 elements make up 96% of living matter
Carbon
Hydrogen
Oxygen
Nitrogen
What is the Atomic Number the same as?
Number of protons
What does the Atomic Weight (Mass #) equal?
Neutrons + Protons
How do you find the number of neutrons?
Atomic Weights - Atomic Number = Neutrons
What is an isotope?
Atoms of the same element, who have the same number of protons and electrons, but have a different number of neutrons
Where are neutrons and protons located?
The nucleus
Where are electrons located?
Orbitals
What is the Octet Rule?
The tendency of most atoms to need 8 valence electrons for stability
Covalent Chemical Bonds:
Result from the sharing of one or more pair(s) of electrons
Are all compounds molecules?
Yes
Are all molecules compounds?
No
What determines how an atom combines with another atom?
Number of Electrons
Where do electrons move when they gain energy?
Farther from the nucleus
What is required to move negatively charged electrons farther away from positive protons?
Energy
How many orbitals are in the first energy level
One
How many electrons can fit in the single orbital within the first energy level
Two
How many orbitals can the second and third energy levels have?
Four
How many electrons can be held in the four orbitals within the second and third energy levels?
Eight
What are the 5 different bonds? (greatest to least)
- Covalent Bonds
- Ionic Bonds
- Hydrogen Bonds
- Hydrophobic Interactions
- van der Waals Interaction
What is the strength of Covalent Bonds? (Kcal/Mole)
50-110
What is the strength of Ionic Bonds? (Kcal/Mole)
3-7
What is the strength of Hydrogen Bonds? (Kcal/Mole)
3-7
What is the strength of Hydrophobic Interactions? (Kcal/Mole)
1-2
What is the strength of van der waals interaction? (Kcal/Mole)
1
What are ions?
Charged Atoms
Anions
negatively charges ion which has gained electron(s)
Cations
Positively charged ions which have lost electron(s)
Define Electronegativity:
An atom’s attraction for electrons
What is the electronegativity of Oxygen?
3.5
What is the electronegativity of Carbon?
2.5
What is the electronegativity of Hydrogen?
2.1
What is the electronegativity of Nitrogen?
3.0
Is it polar or non-polar when electrons are shared equally?
Non-polar
Is it polar or non-polar when electrons are not shared equally?
Polar
What is the electronegativity difference for polar atoms?
0.5 to 1.6
What is the electronegativity difference for non-polar atoms?
0.2 to 0.5
What type of bond is temporary?
van der waals interaction
What do ionic bonds form from?
The transfer of electrons between atoms (due to large differences in electronegativity)
What is a hydrophobic interactions?
When non-polar molecules in an aqueous solution draw together due to their mutual hatred of water
What does chemical properties depend on?
Number of electrons
Are polar molecules hydrophobic or hydrophilic?
Hydrophilic
Are non-polar molecules hydrophobic or hydrophilic?
Hydrophobic
What is a free radical?
an atom or molecule containing one or more unpaired electrons in the outermost shell and is capable of independent existence.
Can cause chain reaction
What can donate electrons to free radicals without becoming one itself?
Antioxidants
True or False:
Atoms with different electronegativity will not share electrons equally
True
When do Hydrogen Bonds form?
Result from the attraction between opposite partial charges in different molecules
Define Endergonic
When energy has to be input to produce larger, more complex molecules
Define Exergonic:
When energy is given off in breaking down large complex molecules to smaller, less complex molecules
What is the measure of energy in chemical reactions?
Calorie
What is a calorie
Amount of heat energy needed to raise the temperature of one gram of pure water form 14.5 to 15.5 degrees Celsius
Define Concentration:
How much substance is dissolved in water
What is concentration measured in?
Molarity
CH4
Methane
C6H12O6
Glucose
C6H12O6
Fructose
Equation for finding how much substance is needed to make something:
MW x M x L
What is Avogadro’s Number?
6.023 x 10^23
Define Mole:
The amount of pure substance whose weight in grams is numerically equal to the Molecular Weight of the substance
What is an acid?
A proton donor, when a substance gives off a proton
What is a base?
Anything that accepts a proton and decreases Hydrogen Ion concentration
What is pH a measure of?
How many H+ ions are present in
What range of pH is acidic?
0-7
High hydrogen ion concentration
What range of pH is basic?
7-14
low hydrogen ion concentration but higher hydroxyl ion concentration
What is the neutral pH
7
When the pH of a solution changes from 3 to 5 the Hydrogen ion concentration decreases by…?
100x
When the pH of a solution changes from 8 to 5, the Hydrogen ion concentration increases by…?
1000x
What is a buffer?
Compounds that resist pH changes
What are most buffers combinations of?
weak acids and weak bases
What is the normal pH of blood?
7.4
What decreases Hydrogen ion concentration?
Bases
What increases Hydrogen ion concentration?
Acids
What is the measure of pH?
How many Hydrogen ions are present
What do isotopes help do?
Tag molecules to follow biochemical pathways and cancer treatment
What is the equation to calculate the amount of substance needed?
MW x M x L