Final Exam Review Questions
You will be given a Periodic Table, Activity Series, and a Common Ions Chart
CP CHEMISTRY
Part A True-False
State whether each statement is true or false. If
false, correct it so that it is a true statement.
1. Complete combustion has occurred when all the carbon in the product is in the form of carbon dioxide. (True)
2. A single product is the identifying characteristic of a decomposition reaction. (False )
3. You can predict the products of a reaction without doing the reaction. (False)
4. All chemical reactions can be classified as one of five general types. (False)
5. With solutions of strong acids and strong bases, the word strong refers to ability to turn into ions. (False)
6. A 12 M solution of an acid that is able to ionize completely in solution would be termed concentrated and strong. False
7. Sour taste is a property of an acid. False
8. Only acids react with metal to form H2 gas. True
9. A change in pH cause indicators to change color False
10. Acids and Bases are strong electrolytes False
11. A solution which has [H+] of 1.0 x 10-7 M is netural. False
12. A solution that turns red litmus blue is strongly basic. True
13. The presence of a catalyst is one of a few factors that affect the rate of a chemical reaction. False
14. [H+] = 2.0 x 10-7M is an acidic solution True
15. [OH-] = 1.0 x 10-8M is an acidic solution. False
16. Mg (OH) 2 is an Arrhenius base.True
17. NH3 is an Arrhenius base False
18. H2CO3 is diprotic False
19. HCl + H2O (aq) ó Cl- (aq) + H3O+ (aq) In the reaction, H2O is acting as a Bronsted-Lowry base. False
20. NH3 + H2O ó NH4+ + OH- is a Brønsted-Lowry acid-base reaction. True
21. Indicators are weak acids or bases that undergo dissociation in a known pH range. True
22. Indicators can be used to determine the pH of a given solution. True but not in great detail.
23. Indicators exhibit different colors across the range of pH values for which they are used.
True
Part B Problem Solving
Solve each problem below, showing all work when appropriate.
Classify each reaction in questions #1 – 8 as one of the following: Single replacement, Double replacement, Composition (synthesis), Decomposition, Neutralization, or, Combustion.
1. HgO ---> Hg + O2 Decomposition
2. S8 + O2 ---> SO3 Synthesis
3. 4 Fe + 3 O2 ---> 2 Fe2O3 Synthesis
4. CH4 + 2 O2 à CO2 + 2 H2O Combustion
5. Ca(OH) 2 + 2 HCl à CaCl2 + 2 H2O DR
6. Al(OH)3 + H2SO4 ---> Al2(SO4)3 + H2O DR
7. Fe2(SO4)3 + KOH ---> K2SO4 + Fe(OH)3 DR
8. C2H5OH + O2 à HC2H3O2 + H2O Neutralization
9. Write a balanced reaction for Hydrocyanic acid reacting with barium hydroxide.
HCN + Ba(OH)2à Ba(CN)2 + H2O
10. How many molecules are contained in 1.25 moles of Au?
1.24 mol x 6.02 *1023 molecules =
1 mole
= 7.46 *1023 molecule
11. What is the gram formula mass of Fe(OH)3?
Fe – 55.85*1 = 55.85
O – 16.00 * 3 = 48.00
H – 1.01 * 3 = __3.03____+
106.88 g/mol
12. Find the mass, in grams, of 5.20 moles of H3PO4.
3.03 + 30.97 + (16*4)= 98.00 g/mol
5.20 mol x 98.00 g = 509.60 g H3PO4
1 mole
13. What is the volume, in liters, of 6.5 mol of carbon monoxide? AT STP
6.5 mol x 22.4 L = 145.6 L
1 mole
14. The chemical formula for glucose is C6H12O6. What is the mass of 0.430 mol of this sugar?
0.430 mol x 180.18 g = 77.48 grams
1 mole
15. How many atoms are there in 3.24 grams of Cu2CrO4?
3.24 g x 1 mole x 6.02 x 1023 molecules x 7 atoms
243.1 g 1 mole 1 molecule
= 5.62 * 1022 atoms
16. What is the volume, in liters, of 1.87 x 1022 molecules of Br2? AT STP
1.87 x 1022 molecules x 1 mole x 22.4 L
(6.02 *1023) 1 mole
= 0.70 L
17. Calculate the percent composition of chlorine in AlCl3.
Al – 26.98
Cl- 35.45 *3 = 106.35
%Al – 26.98 / 133.33 x 100 = 20.24 %
% Cl – 106.35 / 133.33 x 100 = 79.76 %
18. Calculate the mass of carbon in 145.0 grams of methane, CH4.
% C = 12.01 / (12.01 + 4.04) x 100=74.82% C
.7482 (145) = 108.49 g C
19. Calculate the empirical formula of a compound that is 3.05% carbon, 0.26% hydrogen, and 96.69% iodine.
3.05 g C / 12.01 = 0.25 mol C / 0.25= 1
0.26 g H / 1.01 = 0.26 mol H / 0.25= 1
96.69 g I / 126.90 = 0.76 mol I/ 0.25= 3
CHI3
20. Determine the molecular formula of a compound that is composed of 70% carbon, 3% hydrogen, and 27% nitrogen and its gram formula mass = 206g.
C: 70/12.01 = 5.83 / 1.93 = 3 * 2= 6
H: 3/1.01 = 2.97 / 1.93= 1.5* 2= 3
N: 27/14.01 = 1.93/ 1.93= 1* 2= 2
C6H3N2 = 103.11
206/103 = 2
C12H6N4
21. Write a skeleton equation for the reaction in which aqueous sodium chloride reacts with aqueous silver nitrate to produce aqueous sodium nitrate and solid silver chloride. Remember to include the states and to write the correct formulas for each compound. You do not have to balance this equation.
NaCl(aq) + AgNO3(aq) à AgCl(s) + NaNO3(aq)
Balance each equation in #22-25.
22. Zn + 2 HCl ---> ZnCl2 + H2
23. SiCl4 + 4 H2O ---> H4SiO4 + 4 HCl
24. Na + H2O ---> NaOH + H2
25. 2 H3PO4 --- H4P2O7 + H2O
For questions #26 – 31, predict the end products and write a correctly balanced equation using the correct formulas.
26. sodium metal and chlorine
2 Na + Cl2 à 2 NaCl
27. calcium phosphate and sulfuric acid
Ca3(PO4)2 + 3 H2SO4 à 3 CaSO4 + 2 H3PO4
28. phosphoric acid plus sodium hydroxide.
H3PO4 + 3 NaOH à Na3PO4 + 3 H2O
29. propane (C8H5) burns in the presence of oxygen
4 C8H5 + 37 O2 à 32 CO2 + 10 H2O
30. zinc and copper II sulfate
Zn + CuSO4 à ZnSO4 + Cu
31. iron (II) chloride decomposes
2 FeCl3 à 2 Fe + 3 Cl2
32. Identify the spectator ions and write a balanced net ionic equation for LiOH (aq) + H2SO4 (aq) àLi2SO4(aq) + H2O (l)
Spectators – Li+ and SO4-2
OH- + H+ à H2O
33. A sample of gas occupies a volume of 71.0 mL at a pressure of 0.50 atm and a temperature of 0.0oC. What will its pressure be (in mmHg) at a volume of 80.2 mL and a temperature of 50.0oC?
PV = P2V2 0.50(71.0) = (P)(80.2)
T T2 273.15 323.15
P = 0.52 atm
34. What is the temperature of the gas inside a 250 mL balloon filled with 0.050 g H2 gas? The pressure of the balloon is 110 kPa.
PV=nRT 0.05 g H2 / 2.02 = .025m ol H2
110kPa/133.32 = .83atm
(0.83)(0.25) = (.025)(0.0821)(T)
T = 101.10 K
35. In the given unbalanced reaction, how many moles of water are produced when 2.5 mole of Na2CO3 are formed in the reaction?
2 NaHCO3 àNa2CO3 + CO2 + H2O
2.5 mol Na2CO3 x 1 mole H2O = 2.5 mole H2O
1 mole Na2CO3
36. How many moles of carbon dioxide are produced from 67.0 grams of Fe2(Cr2O4)3 according to this unbalanced equation? Fe2 (Cr2O4)3 ---> FeC2O4 + CO2
Oops! Reaction is too flawed to do problem!
37. How many grams of H2 are needed to react with an excess of Au2S3 to produce 513 grams of Au? The unbalanced equation for the reaction is:
Au2S3 + 3 H2 ---> 2 Au + 3 H2S
513g Au x 1 mol x 3 H2 x 2.02 g H2 = 7.89 g H2
197g 2 Au 1 mole
38. How many grams of Zn are needed to produce 7.00 L of H2 according to the unbalanced reaction?
Zn + 2 NaOH + 2 H2O---> Na2Zn(OH)4 + H2
7.0 L x 1 mole x 1 Zn x 2.02 g = .63 g H2
22.4 L 1 H2 1mole
39. According to the following unbalanced equation 3 Hg(OH)2 + 2 H3PO4 ---> Hg3(PO4)2 + 6 H2O, how many molecules of water will be produced from 35.3 grams of Mercury (II) hydroxide?
35.3 g x 1 mol x 6 H2O x 6.02 x 1023 molecules
234.62g 3Hg(OH)2 1 mole
= 1.81*1023molecules
40. 6.0 grams of Aluminum burns in 30 L of bromine gas, producing aluminum bromide according to the following unbalanced equation.
2 Al (s) + 3 Br2 (l) à 2 AlBr3 (s)
a. What is the limiting reagent?
6g Al/ 26.98 = 0.22 mol Al
30L Br2/ 22.4 = 1.34 mol Br2 x 2Al/3 Br2 = .89molAl
Al is the limiting
b. How much AlBr3 should be produced?
0.22 mol Al x 2 AlBr3/2Al = 0.22 mol AlBr3
c. What chemical is in excess and by how much?
Br2 is in excess. 1.34 - .33 = 1.01 mol left over
d. If the experiment only produced 50.3
grams of aluminum bromide, what is the percent yield for this experiment?
50.3 g AlBr3- experimental yield
0.22 mol x 133.33 g /mole = 29.33 g- theor. Yield
50.3/29.33 x 100 = 171.48% yield
41. In a calorimeter, 30 g of water absorb 1500J of heat. If the water started at a temperature of 42oC, what is the final temperature of the water?
q = mCDT
1500 = 30(4.18)(Tf – 42) Tf = 53.96oC
42. What is the specific heat capacity of a 75g sample of unknown metal that experiences a 14oC temperature change when 1250J of heat is absorbed?
q= mCDT
1250 = 75(C)( 14)
C = 1.19 J/goC
Given each of the following concentrations, find the pH
43. [ H+ ] = 1.0 x 10-3M
pH = -log(1.0 x 10-3) =3
44. [ H+ ] = 5.4 x 10-12M
pH = -log(5.4 x 10-12) =11.3
45. [OH- ] = 1.0 x 10-10M
pOH = -log(1.0 x 10-10) =10
pH= 14-10 = 4
46. [ OH- ] = 7.9 x 10-1M
pOH = -log(7.9 x 10-1) =0.10
pH = 14-0.10= 13.90
Given the following pH or pOH, find the [H+]
concentration.
47. pH = 13
[H+] = 10-13
48. pH = 2.7
[H+] = 10-2.7= 1.99*10-3M
49. pOH = 2
pH = 14-2 = 12
[H+]= 10-12
50. pOH = 7.4
pH = 14-7.4 = 6.6
[H+]= 10-6.6= 2.51*10-7M
Write the names or formulas of the following acids or bases.
51. oxalic acid HC2O4
52. lead (II) hydroxide Pb(OH)2
53. H2CrO4 Chromic Acid
54. Sr(OH)2 Strontium hydroxide
55. H2CO3 Carbonic Acid
56. Hydrofluoric acid HF
Final Exam Review – Part II
Identify each of the following types of matter using the choices below. Choose one from the left group of choices AND one from the right group of choices.
(A) Homogeneous or (B) Heterogeneous AND (1) Element, (2) Compound, or (3) Mixture
1. Oxygen gas __A______1___
2. Carbon Dioxide __A______2___
3. Salt __A______2___
4. Gold __A______1___
5. Salad dressing __B______3___
6. Iron __A______1___
7. Iron (II) Chloride ___A______2___
8. A team of students determined the volume of a 26-g piece of wood to be 50 cm3. A handbook of chemistry reported a density of 0.513 g/cm3 for the same type of wood. What is the percent error of the students’ values?
Show all work, including equations used and units in all steps.
D = M/V
D = 26/50= 0.52g/cm3
% error = measured – accepted/accepted x 100
% error = (0.52-0.517)/(0.517) x 100 = 0.58% error (wow that’s accurate!)
Name three physical or chemical properties that could be used to distinguish between these substances:
9. Water and salt water ___boiling point______flavor______reactivity with Ag+_
10. Tin and copper __color ______density______reactivity _____
11. Fluorine and neon gases __reactivity/inertness__ __color of gas __ color of light given off by e-_
Classify each of the following as a chemical change (C) or a physical change (P).
12. Baking bread _c___
13. Evaporating water __p____
14. Cutting hair __p____
15. Beating eggs __p____
16. Heating iron __p____
17. Dissolving hot chocolate in water __p____
18. How many protons, electrons and neutrons are in Carbon-14? ___p=6, n=8, e = 6_____
19. How many protons does an atom of magnesium have? ___p= 12______
20. In which group in magnesium found? __group 2______
21. What is the name of magnesium’s chemical family? __alkaline earth metals___
22. How many valence electrons does magnesium have? __2______
23. Is magnesium a metal, a nonmetal, or a metalloid? __metal______
24. How does its atomic radius compare to Calcium’s? __smaller______
25. How does its electronegativity compare to sodium’s? __larger______
26. What ion is magnesium most likely to form in compounds? __+2______
27. What is magnesium’s noble gas configuration? __[Ne]3s2______
28. What would be the electron configuration (not noble gas way!) for an atom of silver?
Ag #47
1s22s22p63s23p64s23d104p65s24d9
Write the names of the compounds listed in numbers 29-32.
29. Na2O __sodium oxide_____
30. SBr2 ___sulfur dibromide______
31. Fe2(C4H4O6) 3 __iron III tartrate_____
32. HCl ___hydrochloric acid_____
Write the formulas of the compounds listed in numbers 33-37.
33. Copper (I) Phosphate _____Cu3PO4______
34. Tetracarbon dichloride ____C4Cl2______
35. Lithium Oxide _____Li2O______
36. Diphosphorus pentoxide _____P2O5______
37. Phosphoric acid ___H3PO4______