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WorksheetsAP Chemistry Midterm Practice
Total questions: 60
Worksheet time: 10hrs 0mins
What 2+ ion has this ground-state electron configuration?
Ca2+
Ni2+
Zn2+
Ge2+
Determine the standard enthalpy of reaction for the following reaction:
2 CH3OH (l) + 3 O2 (g) --> 2 CO2 (g) + H2O (l)
-440.6 kJ
-1276.8 kJ
-1452.8 kJ
-2407.6 kJ
Calculate the enthalpy of calcium carbonate for the following reaction:
CaO (s) + CO2 (g) --> CaCO3 (l)
-178.3 kJ
-965.3 kJ
-2235.5 kJ
-4077.5 kJ
Which of the following are correct Lewis structures for SO2?
1 only
2 only
3 only
2 and 3
How many sigma and pi bonds are in the following molecule?
two σ and nine π
two σ and seven π
seven σ and two π
nine σ and two π
Which of the following are resonance structures for nitrite ion, NO21-?
1 and 2
1, 2, and 3
2 and 3
3 and 4
What is K?
8.6 x 10-6
3.4 x 10-20
1.2 x 105
3.0 x 1019
Which of the following compounds is weak acid?
HCl
HNO3
HF
H2SO4
Which of the following molecules or ions is amphiprotic?
H3 PO4
NH41+
HCO31-
HBr
What is the pH of 4.5 x 10-3 M NaOH (aq) at 25 oC?
2.35
5.40
8.60
11.65
Which of the following compounds will give rise to an acidic solution in water?
KNO3
Na2CO3
NH4Cl
NaCH3COO
Which of the following species will give rise to a basic solution in water?
NH4Br
LiBr
KCN
Na2SO4
The Ka for acetic acid (CH3COOH) is 1.8 x 10-5 at 25 oC. What is the Kb for acetate ion (CH3COO1-)?
1.0 x 10-14
1.8 x 109
5.6 x 10-10
5.6 x 10-20
The pH of a 0.351 M CN1- solution is 11.47. What is the Kb CN1-?
3.3 x 10-23
9.7 x 10-12
2.5 x 10-5
8.4 x 10-3
Which of the following chemical reactions correspond to the acid ionization constant Ka for hydrogen carbonate ion (HCO31-)?
HCO31- + OH1- ↔ CO32- + H2O
HCO31- + H3O1+ ↔ CO2 + 2 H2O
HCO31- + H3O1+ ↔ H2CO3 + H2O
HCO31- + H2O ↔ CO32- + H3O1+
What is the pH of 0.50 M CH3COO1- at 25 oC? The Ka for acidic acid CH3COOH is 1.8 x 10-5
2.52
4.78
9.22
11.48
For the following reaction; N2 + O2 ↔ 2 NO
the equilibrium constant, K, is 6.7 x 10-10 at 900 K. What is the equilibrium constant for the reaction below?
NO ↔ 1/2 N2 + 1/2 O2
6.7 x 10-10
3.9 x 104
2.6 x 10-3
1.5 x 109
The reaction: 2 NO2 ↔ N2O4
is studied at 298 K. Initially, 0.401 mol NO2 is placed in an empty 1.0 L flask. At equilibrium, the concentration of N2O4 is 0.184 mol/L. Calculate K for the reaction.
3.9
1.7 x 102
5.6
5.9 x 10-3
H2 + I2 ↔ 2 HI Kc = 0.504 at 25 oC
If initial concentrations of 0.170 M H2 and 0.170 M I2 are allowed to equilibrate what is the equilibrium concentration of Hl?
0.445 M
0.0891 M
0.0684
0.0706
Assume that the following endothermic chemical reaction is at equilibrium.
C (s) + H2O (g) ↔ H2 (g) + CO (g) ΔH = 131.3 kJ
Which one of the following changes will cause the reaction to shift to the right creating more products?
decreasing the temperature
increasing the pressure
removal of a gaseous product
addition of solid carbon
What is the maximum number of hybridized orbitals that can be formed by a nitrogen atom?
2
3
4
6
In which of the following molecules does the carbon atom have sp2 hybridization?
H2CO
CH2Cl2
CH4
CO2
What is the bond order for a nitrogen ion NO31-?
1
4/3
3/2
2
Based on bond order, predict which molecule has the shortest carbon-oxygen bond length.
CO
CO2
CH3OH
H2CO
Which one of the following molecules is nonpolar?
CH3Cl
SO2
BF3
H2O
Which one of the following molecules is polar?
SF4
XeF4
F2
CF4
What is the formal charge on each atom in CO?
C=-1, O=+1
C=0, O=0
C=+1, O=-1
C=+2, O=-2
Which two of the following compounds are likely to have the lowest melting point? Mark 2.
SiO2
NH3
NaCl
Ms. Laurison's heart
What intermolecular forces or bonds must be overcome in converting SO2 from a liquid to a gas?
London dispersion forces
dipole-dipole forces
hydrogen bonds
London dispersion forces AND dipole-dipole forces
Which of the following molecules will have the highest boiling point?
H2
N2
O2
Cl2
Which is the dominant intermolecular force or bond that must be overcome in converting CH3OH from a liquid to a gas?
London dispersion force
hydrogen bonding
dipole-dipole force
covalent bonding
What is the molecular geometry around an atom that is
sp3 hybridized and has two lone pairs of electrons?
bent
linear
trigonal planar
trigonal pyramidal
One product of the combustion of ethylene, C2H4 , is carbon dioxide. What change in the hybridization of the carbon atoms occurs in this reaction?
sp3 to sp2
sp3 to sp
sp2 to sp
sp2 to sp3
What are the bond angles around an sp2 hybridized central atom?
900
109.50
1200
900 , 1200 , and 1800
Which one of the following compounds forms a network solid composed of covalently bonded atoms?
SiO2
CO2
NH4Cl
NH3
Use VSEPR theory to predict the molecular geometry of SCl2.
bent
trigonal planar
trigonal pyramidal
linear
Use VSEPR theory to predict the bond angles of CCl4.
900
109.50
1200
1800
Use VSEPR theory to predict the molecular geometry of HCN.
bent
linear
trigonal planar
tetrahedral
Use VSEPR theory to predict the molecular geometry of ICl3 .
trigonal planar
trigonal pyramidal
trigonal bipyramidal
T-shaped
2 SO2(g) + O2(g) → 2 SO3(g)
In a 1,000 L flask. 2.00 atm of SO2 react with 5.00 atm of O2. Assuming that the temperature remains constant, what is the final pressure in the flask?
2.00 atm
5.00 atm
6.00 atm
7.00 atm
A mass of 22.8 g of an unknown gas exerts a pressure of 0.912 atm at 78 oC in a 10.0 L flask. What is the molar mass of the gas?
1.56 g/mol
16.0 g/mol
44.0 g/mol
72.0 g/mol
Calculate the density (in g/L) of Ar at 320C and 342 mm Hg. (R = 0.08206 L atm/mol K)
0.615 g/L
0.718 g/L
6.85 g/L
546 g/L
A mixture of H2 and Ne is placed in a 5.00 L flask at 200 C. The partial pressure of the H2 is 1.4 atm and the partial pressure of the Ne is 2.1 atm. What is the mole fraction (mole percent) of H2?
0.014
0.40
0.60
0.67
Carbon dioxide gas diffuses through a barrier at a rate of 0.40 mL/minute. If an unknown gas diffuses through the same barrier at a rate of 0.31 mL/minute, what is the molar mass of the gas?
26 g/mol
39 g/mol
51 g/mol
73 g/mol
The measured pressure of a container of chlorine gas that is at real conditions is lower than the pressure calculated by the ideal gas law. Which of the two statements below is also correct?
1. Nonideality in gas behavior becomes more pronounced as the temperature of a gas is decreased.
2. Nonideality in gas behavior becomes more pronounced as the pressure of a gas is decreased.
1 only
2 only
1 and 2
Which one of the following reactions is NOT a standard enthalpy of formation reaction?
CaO(s) + CO2 (g) → CaCO3 (s)
S(s) + O2 (g) → SO2 (g)
S(s) + 3/2 O2 (g) → SO3(g)
C(s) + 1/2 O2(g) → CO(g)
Place the following atoms in order from smallest to largest atomic radii: F, S, and Cl.
F < S < Cl
F < Cl < S
S < Cl < F
S < F < Cl
Place the following ions in order from smallest to largest iconic radii: N3-, F1-, and Mg2+.
N3- < F1- < Mg2+
F1- < N3- < Mg2+
N3- < F1- < Mg2+
Mg2+ < F1- < N3-
Which of the following groups of elements is arranged correctly in order of increasing first ionization energy?
O < S < Se
Na < K < Rb
O < F < Ne
Cl < Ar < K
A mixture of CaCO3 and CaO has a mass of 2.500 g. After heating, the mass of the sample is reduced to 2.016 g. What is the mass percent of CaCO3 in the mixture?
CaCO3(s) → CaO(s) + CO2(g)
19.4%
44.0%
54.6%
80.6%
Cyclooctene is a hydrocarbon containing only C and H atoms. When burned in oxygen, 1.000 g of cyclooctene produces 3.195 g CO2 and 1.144 g H2O. What is the empirical formula of cyclooctene?
CH2
C2H5
C3H7
C4H7
Which element has the ground state electron configuration: 1s22s22p63s23p2?
Mg
Al
Si
P
Which 3+ ion has the ground state electron configuration: [Ar]3d5?
Sc3+
V3+
Cr3+
Fe3+
What is the ground state electron configuration for a bromine atom?
1s22s22p63s23p5
1s22s22p63s23p64s24p5
1s22s22p63s23p64s23d104p3
1s22s22p63s23p64s23d104p5
What is the ground state electron configuration of a calcium ion?
1s22s22p63s23p6
1s22s22p63s23p64s1
1s22s22p63s23p64s2
1s22s22p63s23p64s24p2
Which of the following atoms is paramagnetic in its ground state?
He
Mg
Li
Ar
Which element does this photoelectron spectrum represent?
Mg
Al
Ne
Na
AgBr (s) ↔ Ag1+(aq) + Br1-(aq)
Kc = 1.5 x 10-16
A solution is prepared by diluting 2.0 mole of AgBr, 1.0 x 10-8 mole Ag1+, and 3.0 x 10-7 mole Br1- to 1 liter. Calculate the reaction quotient and determine whether a reaction occurs.
Q=K; no reaction occurs
Q<K; AgBr dissolves until equilibrium is re-established.
Q>K; AgBr dissolves until equilibrium is re-established.
Q>K; Ag1+ and Br1- react to form AgBr until equilibrium is re-established.
Calculate the average atomic mass of this element.
70
71
72
74
Identify the period 3 element that this IE data represents.
Na
Mg
Al
Cl
