Chapter 2 Flashcards
Covalent bonds
may be single, double, or triple bonds and can vary in orientation and share one or more electron pairs
What is the molecular formula and approximate atomic weight of the following biological molecule?
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH
C14H28O2; 228 Da
Oxygen (O) has an atomic number of 8. What is the approximate atomic mass of an oxygen atom in daltons?
16
Which defines a compound?
A pure substance with a fixed ratio of two or more elements that are combined through bonds
Which particles determine how an atom interacts with other atoms?
Electrons
A(n) _______ is an atom that has gained or lost one or more electrons. A(n) _______ bond is created by a(n) _______ attraction between two _______ atoms.
ion; ionic; electrical; charged
When a chemical reaction occurs, changes in the form of _______ occur, which represents the capacity of the reaction to do _______.
energy; work
A cation has the opposite charge from a(n)
anion.
A helium atom contains
two negatively charged electrons.
The term hydrophobic is the opposite of
hydrophilic
Biological organisms are made of
atoms, elements, water, other molecules, and ions.
If 1 calorie of energy is needed to raise 1 g of water by 1°C, what is the amount of energy needed to raise 15 g of water by 3°C?
45 calories
Water has _______ nonbonding electrons pair(s) and _______ bonding electron pair(s).
2,2
What is the significance of Avogadro’s number?
It is the number of molecules in a mole
How many electrons occupy the 2s orbital in an oxygen atom?
2
What is not an example of a chemical bond or interaction?
Electronegativity
Which six elements provide most of the mass of biological organisms?
C, O, N, H, P, S
What is the maximum number of electrons contained in a single p orbital?
2
Van der Waals interactions are most similar to
weak nonpolar interactions
In the periodic table, when elements are in the same vertical column, they share a similar
number of valence electrons
Buffers demonstrate which important chemical principle?
The law of mass action
Another term for atomic weight is
relative atomic mass
The electronegativity of an atom is a relative measure of the
affinity an atom has for electrons and its ability to capture additional electrons.
Why does sodium chloride (NaCl) dissolve in water?
Water is a polar solvent
The equation C4H10 + 7 O2 → 4 CO2 + 6 H2O + energy is incorrect because
two hydrogen atoms are missing from the reactants
P orbitals are not
found in all atoms with atomic number 2 and higher.
A molecule’s three-dimensional shape varies by _______ without changing the bond angles or its stability.
rotating atoms around a covalent bond
The _______ in an aqueous solution is water.
solvent
______ capacity is a term used to describe the ability of a solution to prevent large changes in pH with the addition of a base or acid.
Buffering
An aqueous solution with a mixture of a _______ acid and its corresponding _______ is called a(n) _______.
weak; base; buffer
In which column/group in the periodic table would you expect to find elements with five valence electrons?
The group that starts with N
Which atom, sodium or chloride, is more electronegative? Which will “steal” an electron from the other?
chloride; chloride
In the periodic table, why are hydrogen, lithium, and sodium in the same column?
They have the same number of unpaired electrons
If carbon dioxide has a molecular weight of approximately 44, then 0.25 moles of carbon dioxide has
a molecular weight of 11
Which orbitals would you expect to be occupied in a fluorine atom?
1s, 2s, 2px, 2py, 2pz
H3C - CH3
Nonpolar
_______ is the heaviest isotope of the element whose atomic number is 1.
Tritium
Living organisms obey the same laws of _______ and _______ as everything else on our planet.
chemistry; physics
The Bohr model of an atom does not emphasize
the relationship between s orbitals and p orbitals
Why does a water molecule have a tetrahedral shape?
Because oxygen bonds to two hydrogen atoms and oxygen contains two sets of unpaired electrons
H3C - OH
Polar
A double covalent bond involves how many electrons?
4
An orbital determines the _______ and _______ of its corresponding electron shell.
energy level; orientation and geometry
What best explains how atoms change partners when propane combusts?
Oxygen breaks a bond with oxygen and forms a bond with carbon or hydrogen.
Hydrogen bonds are most similar to
polar interactions.
