CHM02 WW2.1 Reviewer
Which of the following is an intermolecular force exhibited in a solution of CH3OCH3 in CH3OH? Select all that apply.
- Dispersion forces - Hydrogen bonding - Dipole-dipole forces
Which of the following intermolecular forces help to stabilize a DNA double helix? Select all that apply.
- Ion-dipole forces - Hydrogen bonds - Dispersion forces
Will HCl (g) or NaCl (s) be more soluble in the solvent CH3OCH3? Why?
- The dipole-dipole forces in an HCl solution are similar in strength to the dipole-dipole forces between CH3OCH3 molecules. - HCl (g) will be more soluble in CH3OCH3.
A solution contains 44.0 mL of benzene (C6H6; d = 0.877 g/mL) in 125 mL of hexane (C6H14; d = 0.660 g/mL). Select all the options that correctly show the calculations needed to calculate both the mass % and the volume % of the solution.
- mass of hexane = 82.5 g - mass % = 38.6g/121.2g × 100 = 31.8% w/w - The molecular formulas and molar masses of the compounds are not required for this calculation.
For very dilute solutions, two terms are often used to express concentration (type the abbreviation):
- mass of solute/mass of solution x 10^9=ppb - mass of solute/mass of solution x 10^6=ppm
Which of the following options give the correct formula to calculate the concentration of a solution in ppm and ppb by mass? Select all that apply.
- ppm = mol of solute/mass of solution x 10^6 - ppb = mol of solute/mass of solution x 10^9
A solution contains 16.5 g naphthalene (C10H8; molar mass = 128.16 g/mol) in 53.3 g of benzene (C6H6; molar mass = 78.11 g/mol). Select all the options that show the correct calculations required to determine the mole fraction of naphthalene.
0.159 and 0.682 mol
A solution is prepared by mixing 10.5 g of NaCl (molar mass 58.44 g/mol) with 147 g of H2O (molar mass 18.02 g/mol). The final volume of the solution is 150. mL. Which of the following options are the correct values for molarity (M) and molality (m) of the solution? Select all that apply.
1.20 M and 1.22 m
Concentrated aqueous HCl contains 38% w/w HCl. Calculate the mass of water present in 250. g of this solution.
155 g
What mass of CCl4 is required to prepare a 0.25 m solution using 115 g of hexane? (Molar mass of CCl4 = 153.81 g/mol and molar mass of hexane = 86.17 g/mol.)
4.42 g CCl4
A solution of volume 150. mL contains 0.015 g of Pb2+ ions. Calculate the concentration of Pb2+ in ppm if the density of the solution is 1.02 g/mL.
98.0 ppm
Ion-induced dipole forces
A nonpolar solute in a polar solvent that also contains dissolved ions
Concentrated
A relatively large amount of solute dissolved in a given quantity of solvent
Dilute
A relatively small amount of solute dissolved in a given quantity of solvent
Unsaturated
A solution that contains less than the equilibrium concentration of dissolved solute; more solute added will dissolve
Ion-dipole forces
An ionic solute in a polar solvent
Hydrogen bonding
CH3OH in H2O
Molarity to molality
Density of the solution
The lower part of the phospholipid (B)
Fatty acid chains or nonpolar tail
Helical and sheetlike segments
H bonds between C=O of one peptide bond and the H-N of another
Dispersion forces
I2 in hexane (C6H14)
Stacked N-containing bases
Interact via dispersion forces
Exterior sugar-phosphate groups
Interact with aqueous surroundings via ion-dipole forces
Protruding side chains into the surrounding cell fluid
Ion-dipole forces and H bonds
Mole fraction to molality
Molar masses
Ion-dipole
NaCl in CH3CH2OH
The upper part of the phospholipid (A)
Organophosphate group or polar-ionic head
Dispersion forces
Present in all solutions; principal intermolecular force when both solvent and solute are nonpolar
Solvent
The component present in the largest amount
Solute
The component present in the smallest amount
Solubility
The maximum amount of solute that can dissolve in a given amount of solvent at a given temperature and pressure
Miscible
The substances are soluble in each other at any quantity
True or false: All gases are miscible with each other.
True
Coupled complementary bases on each side of the double helix chain
connect via H bonds
To convert a concentration unit based on mass to one based on volume, the _____ of the solution will be required.
density
The terms "concentrated" and "dilute" describe the relative amounts of dissolved solute in a given solvent. A(n) _____ solution has a smaller amount of solute in the same amount of solvent than a(n) _____ solution.
dilute;concentrated
I2 (s) has a very low solubility in H2O (l) because the weak _____ forces between I2 and H2O are not strong enough to replace the _____ between the H2O molecules.
dipole-induced dipole;hydrogen bonds
A solution is _____ mixture, meaning it exists in one phase, whereas a colloid is a _____ mixture with two or more phases in its composition.
homogenous;heterogenous
Solvent water molecules will cluster around dissolved ions to form _____, which stabilize the solute in the aqueous solution.
hydration shells
Substances that have similar _____ forces are able to dissolve in each other, giving rise to the phrase "_____."
intermolecular;like dissolves like
Phospholipids self-assemble in water into a lipid bilayer because of _____ intermolecular attractive forces between the polar heads and water and _____ intermolecular attractive forces between the nonpolar tails within the bilayer interior.
ion-dipole;dispersion
Formula for Parts by mass
mass of solute/mass of solution
Formula for Molarity (M)
mol of solute/L of solution
Formula for Molality (m)
mol of solute/kg of solvent
Formula for Mole fraction (X)
mol of solute/total no. of moles present
The ratio mol of solute/L of solution mol of solute L of solution is called the _____ of a solution (symbol M), whereas the _____ (symbol m) of the solution is expressed as mol of solute/kg of solvent mol of solute kg of solvent. For an aqueous solution, these two quantities will be very similar if the solution concentration is _____.
molarity;molality;low
Gases with stronger intermolecular forces are generally _____ soluble than gases with weaker intermolecular forces in a polar liquid like water. A gas that reacts with a solvent will appear to have a _____ solubility.
more;high
The function of a soap molecule arises from its dual polarity. Its nonpolar "tail" interacts with grease while its polar "head" interacts with a solvent like water to wash the grease away.
nonpolar "tail";polar "head"
Proteins that are soluble in water have _____ exteriors and _____ interiors.
polar ionic;nonpolar
The self-assembly of phospholipids into a lipid bilayer is energetically favorable due to the ion-dipole forces that occur between the _____r heads and water at the surface of the bilayer and the _____ forces that occur between the nonpolar tails.
polar;dispersion
An alcohol possesses a(n) _____ hydroxyl (-OH) group and a(n) _____ hydrocarbon chain. Due to this dual polarity, an alcohol is able to dissolve in both polar and nonpolar solvents.
polar;nonpolar
Water-soluble proteins have _____ exteriors and _____ interiors.
polar;nonpolar
A solution that contains the maximum amount of dissolved solute in a fixed quantity of solvent at a particular temperature is called a(n) _____ solution. This type of solution will have some undissolved solute present, which will be in equilibrium with the _____ solute.
saturated;undissolved
When an ionic solute dissolves in water, the ions _____ and each ion becomes surrounded by a cluster of H2O molecules called a(n) _____ shell.
separate;hydration
A solution forms when the attractive forces between the solute and solvent are _____ in strength to the solvent-solvent and solute-solute attractions and are therefore able to replace them.
similar
_____ alcohols are more soluble in water and _____ alcohols are more soluble in nonpolar solvents like hexane
smaller;larger
The most abundant component of a solution is usually called the _____ whereas the other dissolved components are called the _____
solvent;solute
A phospholipid molecule consists of _____ and a(n) _____ head.
two fatty acid chains;organophosphate group
Which of the following statements correctly describe solubility? Select all that apply.
- A concentrated solution contains a relatively large amount of solute in a given amount of solvent - The solubility of a given substance in a particular solvent varies with temperature
Which of the following statements correctly describe gas-liquid solutions? Select all that apply.
- A nonpolar gas will not dissolve readily in a polar solvent. - Gases appear to be more soluble in aqueous solution if they react with H2O after dissolving. - A polar gas will dissolve readily in a polar solvent.
Both soaps and cell membranes rely on the behavior of molecules with dual polarity. Which of the following statements correctly describe this behavior? Select all that apply.
- A soap functions because the nonpolar "tails" of the molecules bond to grease and the polar "heads" carry the grease into the solvent. - The lipid molecules that make up a cell membrane have a nonpolar hydrocarbon portion and a polar-ionic "head." - A cell membrane maximizes contact between parts of the lipid molecules that have the most similar types of intermolecular forces.
Which of the following statements correctly describe the effect of alcohol structure on solubility? Select all that apply.
- As the hydrocarbon chain increases in length, the alcohol becomes less soluble in polar solvents - Smaller alcohol are more soluble in H2O than larger alcohols
Which of the following statements correctly describe solutions consisting of gases and/or solids? Select all that apply.
- Gas-gas solutions form readily because all gases are miscible with each other. - Gas-solid solutions are important as catalysts. - A gas may dissolve in a solid by occupying the spaces between the solid particles.
Which of the following statements correctly describe gas-liquid solutions? Select all that apply.
- Gases appear to be more soluble in aqueous solution if they react with H2O after dissolving. - A polar gas will dissolve readily in a polar solvent. - A nonpolar gas will not dissolve readily in a polar solvent.
A solution of glycerol (C3H8O3; molar mass = 92.09 g/mol) in ethanol (C2H5OH; molar mass = 46.07 g/mol) has a molality of 2.45 mol/kg. Correctly order the steps required to calculate the mole fraction of glycerol in this solution.
- If the molality is 2.45 mol/kg, there are 2.45 mol of glycerol in 1.00 kg of ethanol - 1.00 kg ethanol = 1000 g x 1 mol/46.07 = 21.7 mol ethanol - Total moles = 2.45 mol + 21.7 mol = 24.2 mol = Xglycerol = 2.45/24.2 = 0.101
Which of the following statements correctly describe the molality and molarity of a solution? Select all that apply.
- M must be calculated using the volume of the solution, not the volume of the solvent. - For a dilute aqueous solution molality and molarity are nearly equal. - Both molarity and molality express concentration in terms of moles of solute.
Which of the following statements correctly describe the effect of alcohol structure on solubility? Select all that apply.
- Smaller alcohols are more soluble in H2O than larger alcohols. - As the hydrocarbon chain increases in length, the alcohol becomes less soluble in polar solvents.
Which of the following options describe situations in which hydrogen bonding will be observed between the solute and the solvent? Select all that apply.
- Solvent contains OH and NH groups, solute contains N, O, or F atoms - Solvent contains N, O, or F, solute contain OH or NH groups - Solvent and solute both contains OH or NH groups
Which of the following statements correctly describe different types of mixtures? Select all that apply
- The composition of any mixture is variable - A heterogenous mixture contains two or more different phases - Differences in particle size account for the main differences between solutions and colloids
Certain substances such as alcohols are able to dissolve fairly readily in both polar and nonpolar solvents. Which statements correctly explain this behavior? Select all that apply.
- The hydrocarbon portion of the alcohol interacts with the nonpolar solvent through dispersion forces - Alcohols form strong interactions with both types of solvent - Alcohols have dual polarity since they possess a polar OH group as well as a nonpolar hydrocarbon portion
Which of the following statements correctly describes the action of Gramicidin A and similar antibiotics? Select all that apply.
- The polar interiors of these antibiotics pass along ions using ion-dipole forces. - Vast numbers of ions pass through the antibiotic per second. - These antibiotics form channels in the cell membrane of the bacterium.
An aqueous solution of KCl (molar mass = 74.55 g/mol) has a molality of 0.25 mol/kg and a density of 1.05 g/mL. Which of the options correctly reflect the steps needed to calculate the molarity (M) of the solution? Select all that apply.
- The solution contains 18.6 g of KCl per kg of water - 0.26 M
Which of the following options correctly describe the different ways of expressing the concentration of a solution? Select all that apply.
- To calculate mole fraction for a given mass of a reactant or product, the masses of all solution components must be known. - The unit for molality (symbol m) is mol/kg.
Calculate the mole fraction of KBr (molar mass 119.00 g/mol) in a solution made by dissolving 0.30 g KBr in 0.400 L of H2O (d = 1.00 g/mL; molar mass 18.02 g/mol).
22.2 mol H2O
A person is considered legally intoxicated in most states with a blood alcohol level of 80.0 mg/dL. Calculate this concentration in ppm if the density of blood plasma is 1.023 g/mL.
782 ppm
Dipole-induced dipole forces
A nonpolar solute in a polar solvent
Supersaturated
A solution containing more than the equilibrium concentration of solute; the solution is unstable and solute will separate from it readily
Saturated
A solution containing the maximum amount of dissolved solute; more solute added will not dissolve
Which of the following compounds are expected to be soluble in carbon tetrachloride (CCl4) based on structure? Select all that apply.
C6H6;CO2
Attractions between nonpolar side chains in the protein's interior
Dispersion forces
Mass percentage to molarity
Molar masses and density of the solution
Dipole-induced dipole
O2 (g) in aqueous solution
A protein is a macromolecular polymer consisting of _____ acids covalently bonded together. The _____ of the side chains of these components determine the intermolecular forces between different parts of the same protein molecule, thus influencing the overall _____ and function of a particular protein.
amino;polarity;shape
Gramicidin A and similar _____ function by forming a channel through the cell membrane. The _____ groups along the outside of the channel interact with the membrane interior through _____ forces, while the inside of the channel is lined with polar groups, which allow K+ and Na+ ions to pass through the cell via ion-dipole interactions.
antibiotic;nonpolar;dispersion
Solubility is defined as the _____ amount of solute that is able to dissolve in a fixed amount of a particular solvent at a particular _____ and pressure
maximum;temperature