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Example Questions
Example Question #1 : Intermolecular And Intramolecular Forces
Which of the following best explains the main difference between strong and weak acids or bases?
Weak acids and bases dissociate completely in water
Strong acids and bases are more concentrated than weaker ones
Strong acids and bases always have multiple protons to donate or accept
None of these
Strong acids and bases ionize completely in water whereas weak ones do not
Strong acids and bases ionize completely in water whereas weak ones do not
Molarity has no determination in whether an acid or base is strong or weak. Rather, molarity specifies the concentration of hydroxide or hydrogen ions in a solution. Weak Acids do not completely dissociate in water, while strong acids do. Polyprotic acids, those with more than one proton to donate, do not necessarily determine if an acid is strong (e.g. hydrochloric acid is an example of a strong, monoprotic acid).
Example Question #1 : Intermolecular And Intramolecular Forces
Which of the following molecules would you expect to have the highest boiling point?
In order to answer this question correctly, you must remember the different types of intermolecular forces and their effects.
only contains London dispersion forces. Since it is a smaller molecule compared to the others, it cannot have the highest boiling point.
also only contains London dispersion forces. However, since it is a bigger molecule, it will have a higher boiling point than
.
While contains both London dispersion forces and dipole-dipole interactions, it lacks hydrogen boding as the fluorine atom is attached directly to the second carbon.
has the highest boiling point because it contains London dispersion forces, dipole-dipole interactions, and hydrogen bonding.
Example Question #1 : Intermolecular And Intramolecular Forces
Which molecule will not form hydrogen bonds?
A hydrogen bond refers to the attraction between a hydrogen attached to an electronegative atom of one molecule and an electronegative atom of another molecule. The atoms which commonly form hydrogen bonds are oxygen, nitrogen, and fluorine, which are very electronegative. When a hydrogen bond forms between hydrogen and one of these three atoms, hydrogen gains a partial positive charge while the electronegative atom gains a partial negative charge. Carbon is not a very electronegative atom and thus cannot form a hydrogen bond.
Example Question #1 : Intermolecular And Intramolecular Forces
Is an atomic element, molecular element, molecular compound, or ionic compound?
Ionic compound
Atomic element
Molecular element
Molecular compound
Ionic compound
is an ionic compound because it is composed of a metal and a nonmetal.
Example Question #201 : College Chemistry
Is an atomic element, molecular element, molecular compound, or ionic compound?
Atomic element
Molecular compound
molecular element
ionic compound
Molecular compound
is a molecular compound because it consists of a nonmetal connected to another nonmetal.
Example Question #1 : Intermolecular And Intramolecular Forces
classifying compounds/elements
Is xenon an atomic element, molecular element, molecular compound, or ionic compound?
Molecular compound
Atomic element
Molecular element
Ionic compound
Atomic element
Xenon is an atomic element because its elemental form consists of one atom.
Example Question #4 : Intermolecular And Intramolecular Forces
Which of the following C-N bonds is the shortest?
The C-N bond in .
The C-N bond in .
The C-N bond in .
The C-N bond in .
The C-N bond in .
Drawing the Lewis Diagrams for these molecules reveals that the C-N bond in is a triple covalent bond, whereas the C-N bonds in
and
are double covalent bonds and the C-N bond in
is a single covalent bond. Triple covalent bonds between two given atoms are always stronger than double bonds between these same two atoms, and similarly double bonds are even stronger than single bonds. Bond length is inversely related to bond strength; therefore a shorter bond is a stronger bond, and triple covalent bonds are shorter than either double or single covalent bonds. Thus, the C-N bond in
is the shortest in length.
Example Question #11 : Molecules And Compounds
Three types of intermolecular forces include: hydrogen bonding, London dispersion forces, and dipole-dipole interactions. Which of these is the strongest intermolecular force?
Hydrogen bonding
These are all equally strong
London dispersion forces
Dipole-dipole interactions
Hydrogen bonding
London dispersion forces are the weakest of the three. Every molecule is composed of electrons, which are free to move around. This can create a temporary charge, on any molecule, at any time. When two molecules come close together, their varying charges can orient such that one end of a molecule may be slightly positive, while the end of a nearby molecule may be slightly negative. This leads to a slight attraction between the two molecules, called London dispersion forces until they move around again. This is a weak, temporary force.
Dipole-dipole interactions develop when polar compounds line up and are attracted to each other. These forces are stronger than London dispersion forces due to the permanency of the dipoles, but weaker than hydrogen bonds.
Hydrogen bonds are the strongest force of the three. The name refers to the attractive force between the hydrogen attached to one electronegative atom (usually oxygen, nitrogen, or fluorine) and an electronegative atom of a different molecule. The electronegative atom gains a partial negative charge, while the hydrogen gains a partial positive charge. These forces are responsible for many of the qualities of water.
Example Question #1 : Intermolecular And Intramolecular Forces
Which of the following elements does not exist as a diatomic molecule?
Ne
N
Cl
O
Ne
Ne is the only element that does not exist as a diatomic molecule because it is a noble gas, meaning it has a stable resting valence electron configuration, and exists simply as an atomic molecule. By comparison, N, O, and Cl can all achieve stable states by forming a diatomic molecule. and
are held together by a single covalent bond, or shared electron pair.
is held together by sharing two electron pairs (two covalent bonds), and
by sharing three pairs.
Example Question #2 : Intermolecular And Intramolecular Forces
Molecules experiencing which of the following intermolecular forces will tend to have the highest melting point?
Dispersion/van der Waals forces
Hydrogen bonding
Dipole-dipole interaction
Ion-ion interaction
Ion-ion interaction
Generally, the stronger the intermolecular forces between molecules, the higher a compound's melting point. This trend is due to the fact that in melting, the distance between molecules increases, a process which is counteracted by any intermolecular forces pulling them together. The ion-ion interaction forces between ionic compounds - the attraction of positively charged and negatively charged ions - are the strongest. The greater strength of this intermolecular force is due to the greater separation of charge between species. In decreasing order of strength after that would be hydrogen bonding, dipole-dipole interaction, and dispersion forces. Thus, molecules undergoing ion-ion interactions will have the highest melting point, followed by those undergoing Hydrogen bonding, dipole-dipole interaction, and dispersion in that order.
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