Semester 1 Final: Chemical Context of Life

Question 1

main elements of life

Answer 1

carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur

Question 2

ionic bonds

Answer 2

a chemical bond that forms due to the complete transfer of electrons from one atom to another (formed between ions of opposite charges)

Question 3

covalent bond

Answer 3

A covalent bond is a chemical bond that forms via the sharing (not complete transfer) of valence electrons.

When the electrons are shared unequally, the bond is polar covalent.
When the electrons are shared equally, the bond is nonpolar covalent.

Question 4

hydrogen bond

Answer 4

Hydrogen bonds are intermolecular, which means they occur between two or more different molecules.

a weak chemical bond that forms when a hydrogen atom with a partial positive charge of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule

Question 5

electronegativity

Answer 5

the attraction of an atom for the electrons of a covalent bond
(i.e. electronegativity of oxygen atom in a water molecule results in polarity)

Question 6

van der Waals interactions

Answer 6

weak attractions between molecules or parts of molecules that are brought about by localized charge fluctuations

Question 7

chemical reactions

Answer 7

make and break chemical bonds
reactants are converted into products; most reactions are reversible
chemical equilibrium: the point at which the rate of the forward chemical reaction equals the rate of the reverse reaction (concentration of reactants and products have stabilized at a particular ratio)