CHM 142 FINAL EXAM 2024 QUESTIONS AND
ANSWERS (VERIFIED)
What is the total concentration of ions (in mol/L) in a solution obtained by dissolving 3.51 g of Cr(NO3)3
in enough water to make 351 mL of solution?
(Molar mass of Cr(NO3)3: 238.01 g/mol)
0.168 +/- 1%
What is the concentration of sodium ions (in mol/L) in a solution obtained by mixing 90.5 mL of 0.181 M
solution of Na2SO4 and 65.5 mL of 0.147 M solution of Na3PO4?
Assume that volumes are additive.
0.395
Which of the following molecules is polar?
IF5
What is the mole fraction of ethanol in a solution obtained by mixing 4.87 g of C2H5OH and 13.9 g of
H2O?
0.121
Which of the following four compounds
,CH3Cl, CH3NH2, CH3COOH, CH3CH3
can form strong hydrogen bonds with water molecules? (Drawing Lewis structures is useful.)
CH3NH2 and CH3COOH
Which one of the following compounds is most soluble in hexane (C6H14)?
ethanol (CH3CH2OH)
Which one of the following compounds is least soluble in water?
-methylamine (CH3NH2)
-potassium chloride (KCl)
-methanol (CH3OH)
-ethylene glycol (HOCH2CH2OH)
-pentanol (CH3(CH2)4OH)
pentanol (CH3(CH2)4OH)
Carbon tetrachloride (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), carbon disulfide (CS2) and
acetonitrile (CH3CN) are common solvents. How many of them can be used to dissolve polar substances
and how many to dissolve nonpolar substances?
(Hint: draw Lewis structures of all five compounds and determine their polarity.)
3 can dissolve polar substances, 2 can dissolve nonpolar substances.
Which of the following statements is true?
, -The solubility of gases in water increases with increasing temperature.
-When two substances are mixed the entropy usually increases.
-The weaker attractions between the solute and solvent molecules result in a greater solubility.
-Ionic substances tend to dissolve in nonpolar solvents.
-Substances with different intermolecular attractive forces tend to be soluble in one another.
When two substances are mixed the entropy usually increases.
What conditions of pressure and temperature among those given below will result in the highest
concentration of O2 in water?
P = 2.0 atm, T = 15 ºC
P = 1.0 atm, T = 10 ºC
P = 5.0 atm, T = 5 ºC
P = 2.0 atm, T = 5 ºC
P = 5.0 atm, T = 25 ºC
P = 5.0 atm, T = 5 ºC
What is the total concentration of ions (in mol/kg) in a solution obtained by dissolving 3.69 g of
Zr(NO3)4 in 330.6 g of water?
(Molar mass of Zr(NO3)4 = 339.24 g/mol)
0.164
What is the molality (in mol/kg) of a 9.191 mol/L aqueous solution of solute A (molar mass = 47.84
g/mol)? The density of this solution is 1.045 g/mL.
15.18
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