CHEM 177 Final Exam Review
Sunday, May 1
6:00pm - 9:00pm
EXAM 1:
1)Which of the following is a physical property?
a)Reactivity
b)Solubility
c)Heat of combustion
d)Half life
2)Which of the following is a chemical property?
a)Enthalpy of Fusion
b)Hardness
c)Color
d)Flammability
3)How long is the pencil?
a)3in
b)3.25in
c)4in
d)3.3in
4)What happens if you change the number of protons?
a)Change the identity of the element
b)Create an isotope
c)Create an ion
5)What happens if you change the number of neutrons?
a)Change the identity of the element
b)Create an isotope
c)Create an ion
6)What happens if you change the number of electrons?
a)Change the identity of the element
b)Create an isotope
c)Create an ion
7)
symbol / 19F1- / Cr 2+Protons / 16
Neutrons / 16 / 28
Electrons / 16
Charge / 2+
8) Express the answer in sig figs:
(17.98+12)/3.459
9) Express the answer in sig figs:
(17.98*12)-3.459
10) You run a 5.0km race in 32 min, what speed were you going in miles/hour (1600 meters in a mile)
11) Rubidium has two naturally occurring isotopes, 85Rb (relative mass 84.9118 amu) and 87Rb (relative mass 86.9092 amu). If rubidium has an average atomic mass of 85.47 amu, what is the abundance of each isotope (in percent).
13) fill each square with the CHEMICAL FORMULA (and the charges)
Hypochlorite= / Chlorite= / Chlorate= / Perchlorate=Hyponitrite= / Nitrite= / Nitrate= / Pernitrate=
Hypocarbonite= / Carbonite= / Carbonate= / Percarbonate=
Hyposulfite= / Sulfite= / Sulfate= / Persulfate=
Hypophosphite= / Phosphite= / Phosphate= / Perphosphate=
13) Name the following or write the chemical formula
NaOH
Calcium Acetate
Cl2 O3
K2 SO4
Lead (II) Carbonate
Cu(OH)2
Dinitrogen Tetroxide
14)What is the empirical formula for:
C6H12O6 H2O2 MgCl2 Na4Cl4
15)What is the molecular formula for:
Sodium Sulfide Ammonia (Nitrogen Hydride) Magnesium Sulfide Calcium Nitride
16)Write out the chemical formula for the following acids:
Hyposulfurous acid
Perphosphic acid
Hydroiodic acid
CH3COOH
17) Reactions:
a)Ethane and Oxygen combustion
b)Nitrogen and potassium react
18) If 15 grams of copper (II) chloride react with 25. grams of sodium nitrate to produce sodium chloride and copper (II) nitrate, how much sodium chloride can be formed in grams? Write the balanced chemical reaction.
What is the limiting reactant?
If 11.3 grams of sodium chloride are formed in the reaction, what is the percent yield?
How much excess reactant remains?
19)Mg(OH)2 + 2 HCl → MgCl2 + 2 H2O
a)If 10g Magnesium hydroxide is used, how many moles of HCl is necessary to completely use up BOTH the Mg(OH)2 AND the HCl?
b)What is the limiting reactant if we have 34 grams Mg(OH)2 and 45 ml of 0.3M HCl?
c)How many grams of MgCl2 are created if the theoretical yield of 38%?
20)Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass, and has a molar mass of 412 g/mol. What are the empirical and molecular formulas?
21) what is the equation for density?
a)dV=nRT
b)c=d
c)d=m/v
d)d=mlv
22) 3 groups of students measured the mass of a product from the same chemical reaction. The groups recorded data of 8.83 g, 8.84 g and 8.82 g. The known mass of the product from that reaction is 8.60g. The group values are _____.
a) accurateb) precise
c) accurate & precise
d) neither accurate nor precise
EXAM 2:
4,5
1)If you have 45 ml of 0.5M NaOH, how many ml of water do I need to add to make the solution 0.23M?
2)If we combine 56 grams of NaCl(s) with 75 ml of 0.4M MgCl2 to make a solution, what is the concentration of Cl in solution? (Assume the volume of the solid is negligible).
3)Which compound has the highest concentration of Potassium ions?
a)40mL of 5M KCl
b)20mL of 3M K2SO4
c)80mL of 2M KNO3
d)25mL of 2M K3PO4
4) Classify each of the following aqueous solutions as a nonelectrolyte, weak electrolyte, or strong electrolyte.
a)LiClO4
b)HClO
c)CH3CH2CH2OH (propanol)
d)HClO3
e)CuSO4
f)C12H22O11 (sucrose)
5)Write the net ionic equation for each of the following reactions:
a. Pb(NO3)2(aq) + KBr(aq) →
b. NaC2H3O2(aq) + HCl(aq) →
c. Acetic acid is neutralized by barium hydroxide
6)Identify the oxidation number for each element. Which is oxidized? Which is reduced?
SO2 / + / Cr2O72- / → / SO42- / + / Cr3+MnO4- + H2SO3 → Mn2+ + HSO4-
7)Draw an energy diagram for an exothermic process. For an endothermic process.
8)If 34 J of work is done on the system, but 50 J of heat is absorbed from the system, What is the change in internal energy ? Is this an endothermic or exothermic process?
9)Write the heat of formation reaction for NH3 and also for water
10)You drop a block of Al into water. The water is 5.000 times as massive as the metal. You know the water has an initial temperature of 25.00 degrees C and after a long time its temperature is 27.00 degree C. The specific heat of Al is .9000 J/gK. What is the initial temperature of the Al?
11) A 10 gram iron sample at 80 degrees C was placed into a 70 ml bath filled with water that was 25 degrees C. The final temperature was 25.85 degrees C. If the specific heat of water is 4.184 J/gK, what is the specific heat of iron?
12) Given the chemical equation
S(s)+O2 (g) → SO2 (g) dH=-297.1 kJ/mol
how much heat is associated with the formation of 7.99g of SO2(g)?
13) Calculate the enthalpy of the following reaction:
CS2(ℓ) + 3O2(g) → CO2(g) + 2SO2(g)
Given:
C(s) + O2(g) → CO2(g) / ΔH = ΔH = -393.5 kJ/molS(s) + O2(g) → SO2(g) / ΔH = -296.8 kJ/mol
C(s) + 2S(s) → CS2(ℓ) / ΔH = +87.9 kJ/mol
14) Calculate the change in enthalpy, ΔH, when 1.00 g of hydrogen peroxide decomposes.
H2O2(l) → H2O(l) + 1/2 O2(g); ΔH = -98.2 kJ
15) C3H6O (l) + 4 O2 (g) ---> 3 CO2 (g) + 3 H2O (l); ΔH°comb, acetone = -1790 kJ
Using this information together with the data below (values in kJ/mol), calculate the enthalpy of formation of acetone (C3H6O).
ΔH°f, O2: 0
ΔH°f, CO2: -393.5
ΔH°f, H2O: -285.83
16) Calculate the wavelength light emitted by a photon falling from n=4 to n=1.
17) What is the energy of a photon of electromagnetic radiation with a frequency of 6.75*1012Hz? (Planck’s constant is 6.626*10-34m2kg/s)
18) How many photons of microwave radiation with wavelength 425 nm are needed to heat 2 cups of water from 20 oC to 100 oC? 1 cup is approximately 250 mL.
19) If 2 moles of photons gives off 920 kJ of energy what is the wavelength of one photon?
20) How many nodes does a 4s orbital have?
21)Quantum Numbers. Complete the following table:
Number / Letter / Meaning / Possible Values / n=3Principal Quantum Number
Angular momentum Number
Magnetic Quantum Number
Spin Magnetic Quantum Number
22)Which of the following combinations of quantum numbers for an electron is not permissible?
- n=5, l=2, ml=0
- n=3, l=2, ml=3
- n=4, l=3, ml=-2
- n=1, l=0, ml=0
- n=2, l=1, ml=-1
EXAM 4:
8,9
1)Which order is correct when the species are arranged in order of increasing bond length?
a)NO3-,NO2- ,NO+ b)NO+ ,NO3-,NO2- c)NO2-,NO3-,NO+ d) NO+ , NO2-, NO3-
2) Draw the Lewis structures of the following compounds and classify the following compounds as having ionic, covalent, polar covalent or metallic bonding.
Molecule / Lewis Structure / Bond TypeBeF2
BCl3
PBr5
SI6
Carbonate ion
SeS3
COH2
Si2F2
OCl-
Ammonium ion
SeO2
3) For each group of elements below, predict the order of increasing electronegativity.
a) S, Se, Clb) Si, Ge, Snc) B, Ga, O
4) Determine the formal charges of the underlined elements in the following compounds:
i) NO2+
ii) HCN
iii) SO3
iv) SO2
5) What is the ground state electron configuration of Co.
6) Write the noble gas electron configuration of an excited Ag atom.
7) From the list below, choose the ions that are isoelectronic with krypton, then arrange them in order of increasing ionic size
Ag+ Br- Cd2+ Sc3+ Se2- Sr2+ Ti2+ Zn2+
8) How many resonance structures does a phosphite ion have?
9) The image below depicts the molecular structure of Corannulene, an aromatic hydrocarbon. How many sigma and pi bonds are present in one molecule of this this compound?
10)
Chemical Formula / IF5 / PO3- / BH2- / PCl3 / XeF2Lewis structure (with lone pairs
# of electron domains around central atom
3D structure (ball and stick with accurate bond angles)
Electronic Geometry name
Molecular Geometry Name
Expected Bond Angle(s)
Polar?
Hybridization on central atom?
11) Draw the molecular for F2 and calculate the bond order.
Content since past exam:
10, 11
- If the density of a gas is 0.08987 g/L at STP conditions, what is its molar mass?
a)0.08987 g
b)2.01 g
c)249 g
d)89.87 g
e)100 g
2. A sample of Ne(g) occupies 4.0 L at 35 OC at 2.0 atm. What is its new volume if the temperature and pressure are changed to 48 OC and 1.0 atm?
a)0.48 L
b)2.1 L
c)6.2 L
d)7.7 L
e)8.3 L
3. Several commercial drain cleaners contain NaOH(s) and small amount of Al(s). When one of these cleaners is added to water a reaction occurs resulting in the formation of H2 bubbles:
2Al(s) + 2OH-(aq) + 2H2O → 3H2(g) + 2AlO2-(aq)
The purpose of the H2 bubbles is to agitate the solution and thereby increase the cleansing action. According to this equation, how many liters of H2(g) are released when 0.200g of Al are dissolved in an excess of OH- at 25 C and 1.00 atm pressure?
a)1.00 L
b)0.111 L
c)0.0111 L
d)2.72 L
e)0.272 L
4. Palmitic acid, CH3(CH2)14COOH, is an example of fatty acid found in the human body. The heat of combustion of palmitic acid is -9977 kJ/mol. If the standard heat of formation of H2O(l) at 25 C is -285.8 kJ/mol, (hint, what is the heat of formation equation of water?) what volume of hydrogen gas is required to react with oxygen gas at 25 C and 1.00 atm to produce an amount of energy equivalent to combusting 100.0 g of palmitic acid?
How many molecules of hydrogen are required?
5. A 0.1530 g sample of a gas that reacts with ozone in the atmosphere exerts a pressure of 470.g torr in a 50.00 mL vessel at 298.0 K. What is the molecular formula of the gas given its elemental composition: 9.934% C; 58.64% Cl; and 31.43% F.
6. If you have gas with a pressure of 3.4 atm that is composed of 14 grams of Cl2 and 6 grams of Neon, what is the partial pressure of on Chlorine and on Neon?
7. If you have a gas that is 46 percent by mass O2, 13 percent by mass Argon, and 41 percent by mass F2, and the partial pressure of Argon is 0.32 atm, what are the partial pressures on the other two elements?
8. What is the rate of effusion for a gas that has a molar mass thrice that of a gas that effuses at a rate of 4.2 mol/min?
9. Calculate the rate of flow of O2(g) through the walls of a porous tube if H2(g) flows at the rate of 3.95x10-3 mL/s under identical conditions.
10. How much work is done by a gas that expands from 2 to 5 liters against an external pressure of 750 mmHg?
11. Which substance has the highest normal boiling point?
a)CH3Cl
b)CH3Br
c)CH3I
d)CH4
e)CH3OH
12. In liquid SO2, which of the following intermolecular forces operate in the liquid phase: (1) ion-ion; (2) ion-dipole; (3) dipole-dipole; (4) dispersion?
a)(1) and (2)
b)(3) and (4)
c)(1) and (3)
d)(2) and (4)
e)all of them
13. Which of the following has lowest boiling point?
a)HF
b)HCl
c)HBr
d)HI
14. Which of the following has the highest vapor pressure?
a)Ethane, CH3CH3
b)Dimenthyl ether, CH3OCH3
c)Ethyl alcohol, CH3CH2OH
15. Molecules are more likely to evaporate if they have:
(High/Low) Temperature
(High/Low) Kinetic Energy
(High/Low) Intermolecular Forces
(High/Low) Vapor Pressure
(High/Low) Molecular Weight
(High/Low) Surface Tension
16. Calculate the amount of heat needed to convert 96 g of ice at –50 ºC to steam at 110 ºC. c(ice) = 2.06 J/g°C, c(H2O) = 4.184 J/g°C, c(steam) = 1.87 J/g°C, DH(fus) for H2O is 334.J/g, DH(vap) for H2O is 2260 J/g
17. On the phase diagram, the substance exists in which phase on line A?
a)gas and solid
b)gas
c)liquid
d)liquid and solid
e)liquid and gas
18. On the phase diagram, the substance exists in which phase on line B?
a)gas and solid
b)gas
c)liquid
d)liquid and solid
e)liquid and gas
19. On the phase diagram, the substance exists in which phase on line C?
a)gas and solid
b)gas
c)liquid
d)liquid and solid
e)liquid and gas
20. On the phase diagram, the substance exists in which phase at point D?
a)gas and solid
b)gas
c)liquid
d)liquid and solid
e)liquid and gas
f)liquid, gas, and solid
21. What is the critical temperature and pressure?
a)216.6 K and 5.2 atm
b)197.5 K and 1 atm
c)304.25 K and 73 atm
22. At what pressure is the normal boiling point of a substance?
a)760 atm
b)1 torr
c)1 mm Hg
d)1 atm
23. Rank the four intermolecular forces in order of increasing strength.