DAT Chemistry Test Practice
Questions and Answers90
Which of the following interactions is the strongest?
a) hydrogen bonds
b) dipole-dipole forces
c) hydrophobic interactions
d) ionic bonds
e) London dispersion forces - ANSWERS-Ionic bonds (complete transfer of electrons)
Hydrogen bonds are the strongest intermolecular force but not stronger than ionic
What is the maximum # of electrons the d sub shell can hold?
a) 2
b) 6
c) 10
d) 14
e) 18 - ANSWERS-10
S=2
P=6
D = 10
F = 14
etc
,Calcium chlorate (CaCrO4) is a yellow solid with a Ksp of 7.1 x 10^-4. Determine the ion product
constant and whether precipitate would form when an aqueous solution contains 26mM of
Ca2+ and 29 mM of CrO42- - ANSWERS-1. Write out reaction and IP equation:
CaCrO4 (s) -> Ca2+ (aq) + CrO42-
IP = [Ca2+][CrO42-]
2. Convert mM to mole and plug into equation:
IP = 0.026M x 0.029 (moves 3 decimal places)
= 0.000754 = 7.54x10^-4
3. Compare IP value above to Ksp.
IP > Ksp = shift left and ppt forms
IP < Ksp = shift right and ppt doesn't form
A container holds 4.0L of gas at 3.5 atm and a temp of 27 degrees C. If the pressure is reduced
to 0.8 atm without a change in temperature, what would be the volume of the gas? - ANSWERS-
Use: P1V1/n1T1 = P2V2/n2T2
Can assume that n1 = n2 since no change in gas molecules and also for T since it is constant.
Therefore, P1V1=P2V2
(3.5atm)(4.0L)=(0.8)(V2)
V2 = (3.5)(4.0)/(0.8)
V2 = 18
dividing by 0.8 = slightly larger number
,A NaOH solution has a molarity of 2.00M and is titrated with 75mL of 0.5M H2SO4. What
volume of NaOH is needed to reach end point? - ANSWERS-end point - colour change
(equivalence point)
NaOH + H2SO4 -> Na2SO4 + 2H2O
1. Find moles of H2SO4 = molarity x volume
= (0.5mol/L) x 0.0750 L
= 0.0375 x 2 = 0.0750 mol of NaOH
Find volume of NaOH: 0.0750 mol/ 2 mol/L = 0.03650 L
What is the bond angle that exists within a molecule of SO3?
a) 90
b) 104.5
c) 107
d) 109.5
e) 120 - ANSWERS-SO3 = trigonal planer = 120 degree bond angles
An aqueous mixture contains CuF2 and BaF2 (Ksp = 3.0x10^-6). What should be added to the
solution in order to precipitate CuF2?
a) NaF
b) H2O
c) Ba(NO3)2
d) Cu(NO3)2 - ANSWERS-Cu(NO3)2
, According to the following reaction, how many grams of hydrogen gas are formed when 15g of
aluminum react with the excess acid?
2Al + 6HCl -> 2AlCl3 + 3H2 - ANSWERS-1. Determine limiting reagent. Since HCl is the acid
(excess) we know Al will be limiting.
2. Find moles of Al:
mol = mass/ molar mass
mol = 15g/27g/mol
3. Find moles of hydrogen present relative to Al moles: 3 moles of H2 for every 2 Al
moles of H: moles of Al x mole ratio of H to Al
mol of hydrogen = 15/27 x 3mol H2/2mol Al
Al cancels out so (15)(3)/ (27)(2)
4. Find mass of hydrogen: mol of H x molar mass
[(15)(3) / (27)(2)] x 2 (cancels out so) (15)(3)/27
Which of the following elements exists as a diatomic gas and contains a double covalent bond?
a) krypton
b) oxygen
c) nitrogen
d) bromine
e) chlorine - ANSWERS-oxygen (must form double bond)
Also remember nitrogen must form a triple bond
recall: hydrogen, nitrogen, fluorine, oxygen, iodine, chlorine, bromine are all diatomic
Questions and Answers90
Which of the following interactions is the strongest?
a) hydrogen bonds
b) dipole-dipole forces
c) hydrophobic interactions
d) ionic bonds
e) London dispersion forces - ANSWERS-Ionic bonds (complete transfer of electrons)
Hydrogen bonds are the strongest intermolecular force but not stronger than ionic
What is the maximum # of electrons the d sub shell can hold?
a) 2
b) 6
c) 10
d) 14
e) 18 - ANSWERS-10
S=2
P=6
D = 10
F = 14
etc
,Calcium chlorate (CaCrO4) is a yellow solid with a Ksp of 7.1 x 10^-4. Determine the ion product
constant and whether precipitate would form when an aqueous solution contains 26mM of
Ca2+ and 29 mM of CrO42- - ANSWERS-1. Write out reaction and IP equation:
CaCrO4 (s) -> Ca2+ (aq) + CrO42-
IP = [Ca2+][CrO42-]
2. Convert mM to mole and plug into equation:
IP = 0.026M x 0.029 (moves 3 decimal places)
= 0.000754 = 7.54x10^-4
3. Compare IP value above to Ksp.
IP > Ksp = shift left and ppt forms
IP < Ksp = shift right and ppt doesn't form
A container holds 4.0L of gas at 3.5 atm and a temp of 27 degrees C. If the pressure is reduced
to 0.8 atm without a change in temperature, what would be the volume of the gas? - ANSWERS-
Use: P1V1/n1T1 = P2V2/n2T2
Can assume that n1 = n2 since no change in gas molecules and also for T since it is constant.
Therefore, P1V1=P2V2
(3.5atm)(4.0L)=(0.8)(V2)
V2 = (3.5)(4.0)/(0.8)
V2 = 18
dividing by 0.8 = slightly larger number
,A NaOH solution has a molarity of 2.00M and is titrated with 75mL of 0.5M H2SO4. What
volume of NaOH is needed to reach end point? - ANSWERS-end point - colour change
(equivalence point)
NaOH + H2SO4 -> Na2SO4 + 2H2O
1. Find moles of H2SO4 = molarity x volume
= (0.5mol/L) x 0.0750 L
= 0.0375 x 2 = 0.0750 mol of NaOH
Find volume of NaOH: 0.0750 mol/ 2 mol/L = 0.03650 L
What is the bond angle that exists within a molecule of SO3?
a) 90
b) 104.5
c) 107
d) 109.5
e) 120 - ANSWERS-SO3 = trigonal planer = 120 degree bond angles
An aqueous mixture contains CuF2 and BaF2 (Ksp = 3.0x10^-6). What should be added to the
solution in order to precipitate CuF2?
a) NaF
b) H2O
c) Ba(NO3)2
d) Cu(NO3)2 - ANSWERS-Cu(NO3)2
, According to the following reaction, how many grams of hydrogen gas are formed when 15g of
aluminum react with the excess acid?
2Al + 6HCl -> 2AlCl3 + 3H2 - ANSWERS-1. Determine limiting reagent. Since HCl is the acid
(excess) we know Al will be limiting.
2. Find moles of Al:
mol = mass/ molar mass
mol = 15g/27g/mol
3. Find moles of hydrogen present relative to Al moles: 3 moles of H2 for every 2 Al
moles of H: moles of Al x mole ratio of H to Al
mol of hydrogen = 15/27 x 3mol H2/2mol Al
Al cancels out so (15)(3)/ (27)(2)
4. Find mass of hydrogen: mol of H x molar mass
[(15)(3) / (27)(2)] x 2 (cancels out so) (15)(3)/27
Which of the following elements exists as a diatomic gas and contains a double covalent bond?
a) krypton
b) oxygen
c) nitrogen
d) bromine
e) chlorine - ANSWERS-oxygen (must form double bond)
Also remember nitrogen must form a triple bond
recall: hydrogen, nitrogen, fluorine, oxygen, iodine, chlorine, bromine are all diatomic
