Chemical Basis of Life Flashcards
What is the atomic number of an atom?
The number of protons is has.
What is the atomic mass (or mass number) of an atom?
The sum of the number of protons and neutrons.
How are called different atoms that have a different number of protons and neutrons?
Isotopes. (different atoms of the same element that differ in their number of neutrons)
Where is the mass of an atom concentrated?
In the nucleus
Can the precise location of an electron at a given time be found?
No (modern physics)
What are the four most common elements in living organisms?
Carbon, Hydrogen, Oxygen, Nitrogen (CHON)
Are iodide (I) and zinc (Zn) found in living organisms?
Yes, but only in trace amounts
What are the 8 most common elements in living organisms after C, H, O, N?
Sodium (Na), chlorine (Cl), phosphorus (P), sulfur (S), calcium (Ca), magnesium (Mg), iron (Fe), and potassium (K)
What is cohesion?
The tendency of molecules (water?) to stick together due to the presence of hydrogen bonds
What is adhesion?
Polar molecules are attracted to other polar molecules. E.g., water is adhesive to any substance it can form hydrogen bonds with
How are polarity and the possible formation of hydrogen bonds related?
Polar molecules can form hydrogen bonds with other polar molecules. Hence why polar molecules are good solvents for other polar molecules?
What does the term “hydrophilic” refer to?
Any substance that has affinity for water.
What does the term “hydrophobic” refer to?
Any substance that repels water.
Why does water have a high heat of vaporization?
Hydrogen bonds must be broken first.
Why does water have a high specific heat?
Hydrogen bonds absorb heat when they break and release heat when they form. This minimizes temperature changes.
