Organic Chem - Ch 1, 2, & 3 Practice

Which of the following statements correctly describe dipole-dipole interactions? (Select all that apply.)

A molecule must have a permanent dipole to exhibit dipole-dipole interactions. Dipole-dipole interactions are attractive forces that exist between two polar molecules.

Which of the following statements correctly describe the components of a neutral atom? (Select all that apply.)

A neutron has zero electrical charge, whereas a proton is positively charged. The electron cloud that is found outside of the nucleus comprises most of the volume of the atom. The electrons are located outside the nucleus of the atom. Neutral atoms contain equal numbers of protons and electrons. The nucleus contains positively charged protons.

Which of the following statements correctly describe the solubility of different types of compounds?

An organic substance that contains an O or N atom and has five or fewer C atoms is soluble in H2O. Ionic substances generally have low solubility in organic solvents. Ionic substances are generally soluble in H2O.

Which of the compounds shown exhibits the strongest intermolecular forces?

B. Reason: 2-Methylbutane (B) is larger than 2-methylpropane (C) and has a greater surface area than 2,2-dimethylpropane (A). It will therefore have the strongest van der Waals forces.

The ____________ point of a compound is the temperature at which it is converted from a liquid to a gas.

Boiling

Which of the following statements correctly describe the relationship between polarizability and boiling point?

CH3Br is more polarizable than CH3Cl, and so CH3Br will have a higher boiling point

Which of the following statements correctly describe the attractive forces that exist within and between covalent compounds? (Select all that apply.)

Covalent compounds are composed of discrete molecules. Individual molecules attract each other and are held together by intermolecular forces.

Which of the following statements correctly describe the processes involved in the formation of a solution? (Select all that apply.)

Energy required to break up the interactions between the molecules or ions of a solute comes from new interactions between the solute and solvent. Solute-solvent interactions must be similar to solute-solute interactions.

Molecules containing which of the following functional groups are capable of hydrogen bonding with water?

Ethers Amides Carboxylic acids

True or false: A covalent bond between O and H is also called a hydrogen bond.

False. Reason: Correct. The bond between O and H within any molecule is a covalent bond. A hydrogen bond is a non-covalent attraction between a H atom and a lone pair of electrons on an O, N, or F atom in another molecule or a different part of the same molecule. A hydrogen bond cannot exist between two atoms that are already covalently bonded. To participate in hydrogen bonding a H atom must be bonded to N, O, or F.

Which of the following statements correctly describe hydrogen bonding? (Select all that apply.)

Hydrogen bonds are electrostatic attractions between a H atom bonded to N, O, or F and the lone pair of an O, N, or F atom on another molecule. Hydrogen bonding is the strongest type of intermolecular force.

An organic compound tends to be water soluble if it contains one polar functional group that is capable of _______________________ bonding for every _________________ C atoms it contains.

Hydrogen; Five

A polar head matches with ________________________.

Hydrophilic Portion

A non-polar tail matches with ________________________.

Hydrophobic Portion.

Which of the following statements correctly describe vitamin C?

In humans, vitamin C must be obtained from the diet. Vitamin C is water soluble.

Select all statements that correctly describe ionophores.

Ionophores have central cavities that contain O atoms whose lone pairs complex with a given cation. Ionophores move across cell membranes as their hydrophobic exterior interacts with the hydrophobic tails of the phospholipid. The size of the central cavity of an ionphore determines the size of the cation with which the ionophore complexes. Ionophores are organic molecules that complex cations. Ionophores bind ions on one side of the cell membrane in their polar interior.

Which of the following are common biomolecules (organic molecules that are found in biological systems)?

Lipids Alanine(Alanine is an amino acid.) Carbohydrates

The ____________ point of a compound is the temperature at which it is converted from a solid to a liquid.

Melting

Which of the following structural features must remain the same when drawing resonance forms for a species? (Select all that apply.)

Placement of atoms Number of unpaired (single) electrons Placement of single bonds Different resonance forms may have different numbers of lone pairs, but the number of unpaired (i.e., single) electrons remains the same.

Select all factors that influence the strength of van der Waals forces experienced between the molecules of a particular substance.

Surface area of the molecules Polarizability of the molecules

Which of the following statements correctly describe the structure and reactivity of the carbonyl group? (Select all that apply.)

The O atom can act as a basic site. The group is reactive because the π bond is readily broken. The carbon atom is electron deficient.

Which of the following statements correctly describe the changes that occur when a covalent compound boils?

The compound becomes less ordered and intermolecular forces are broken. The stronger the intermolecular forces, the greater the amount of energy required for the change from liquid to gas.

Which of the following can contain a maximum of 2 electrons? (Select all that apply.)

The first shell The 1s orbital A 2p orbital (The second shell can contain a maximum of 8 electrons (2s22p6).)

Which of the following statements correctly describes the term polarizability?

This is a measure of how the electron cloud around an atom responds to its electronic environment.

True or false: A ketone is nucleophilic at the carbonyl oxygen and electrophilic at the carbonyl carbon.

True. The oxygen atom has two lone pairs that make this a nucleophilic site. The polar C=O bond makes the carbonyl carbon an electrophilic center.

Three different types of intermolecular forces that operate between covalent molecules ranked in increasing strength.

Van der Waals, Dipole-Dipole Interactions, Hydrogen Bonding

Retinol is also called _____.

Vitamin A

Select all statements that correctly describe vitamin A.

Vitamin A is fat soluble, and insoluble in water. Vitamin A contains a single OH group and is insoluble in water. Vitamin A has 20 carbons to the single OH group. Vitamin A is an organic compound. Vitamin A is essential to proper functioning of the eyes. Vitamin A is known as retinol.

Which of the following vitamins have several different types?

Vitamin B; Reason: The different B vitamins are differentiated by a subscript (B3, B12, etc.).

Select all statements that correctly describe vitamins.

Vitamins are necessary for normal cell function. Vitamins are organic compounds. Vitamins are identified by a letter, such as A, C, D, E, and K. There are several different B vitamins so a numerical subscript is added to distinguish them. Vitamins must be obtained from our diet. Vitamins can be either fat soluble or water soluble, depending on the functional groups present.

Which of the following options correctly describe the conventions used to represent a tetrahedral arrangement of atoms on a flat plane? Select all statements that apply.

Wedges and dashes are used to represent groups that are aligned one behind another. There will always be one dashed line and one wedged line in the drawing. Solid lines are used to represent any bonds in the plane of the page. There will always be two solid lines showing bonds to the central atom.

Which of the following statements correctly characterize the intermolecular forces involved in the solubility of compounds in polar and nonpolar solvents?

When an ionic compound dissolves in water, the strong ion-ion interactions are replaced by many weaker ion-dipole interactions. Nonpolar organic compounds dissolve in nonpolar solvents because they only display van der Waals forces.

Naturally occurring compounds found in biological systems are called _____.

biomolecules

The attraction between two partial charges on adjacent polar molecules is called a _____ interaction. This interaction is _____ than the van der Waals forces experienced between temporary dipoles.

dipole-dipole; stronger

The greater the surface area of a molecule, the _____ the strength of the van der Waals forces between two such molecules. The strength of the van der Waals forces also depends on the ______ of the molecule.

greater, polarizability. Reason: Molecular shape also has an effect on the strength of van der Waals forces.

The cell membrane is composed of phospholipid bilayers. Phospholipids _____.

have a polar ionic head group have two long hydrocarbon chain The head group of a phospholipid is charged.

Boiling requires energy to overcome the _____ forces between the liquid particles. The stronger these forces, the _____ the amount of energy required to overcome them and the _____ the boiling point will be.

intermolecular; greater; higher

Which of the following molecules can facilitate the transport of cations across a cell membrane?

ionophores. Sucrose is a disaccharide. Ionophores are organic molecules that complex cations, and can help transport them across a cell membrane. Alanine is an amino acid. Ionophores are organic molecules that complex cations, and can help transport them across a cell membrane. Ionophores are organic molecules that complex cations, and can help transport them across a cell membrane.

For two compounds with similar functional groups, the _____ the surface area, the _____ the boiling point.

larger; higher smaller; lower

The boiling point of a compound is the temperature at which a _____ is converted to a _____.

liquid; gas

Acetone (shown) can dissolve in a nonpolar organic solvent such as CCl4 because it has a _____ C-H skeleton and can therefore interact effectively with the CCl4. Acetone can also dissolve in H2O because it has a small C skeleton and the carbonyl group can interact through _____ with H2O.

nonpolar, hydrogen bonding. Reason: C-H bonds are nonpolar since there is a negligible difference in electronegativity between these two atoms. The O atom in acetone is a hydrogen bond acceptor.

The lone pairs on the oxygen atom of the carbonyl group allow it to act as a(n) _____ and as a(n) _____, while the electron-deficient carbon acts as a(n) ______.

nucleophile; base; electrophile

Which of the following are components of soap, at the molecular level?

polar head nonpolar tail

A phospholipid contains one _____ and two _____.

polar head; nonpolar tails

The term _____ is used to describe how well the electron cloud around an atom responds to changes in its electronic environment. A larger atom will hold its valence electrons _____ tightly than a smaller atom and will therefore have a greater response to the presence of a charged or polar particle nearby.

polarizability, less