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Name______________________________Date____________Period________
Final Exam Review Answers
June 2009
1. List the rules for naming acids.
Oxyacid - – ic from - ate, - ous from – ite
Binary Acid – hydro – root – ic from ide
2. Write the formulas for the following acids.
chloric acid
____HClO3-1_______________
phosphorous acid
____ H3PO3-3_________
sulfuric acid
_____ H2SO4-2________
3. Name the following acids.
HCl
___Hydrochloric Acid______________
H2S
____Hydrosulfuric Acid________________
HNO2 ____Nitrous Acid______________
4. Define the term isotope. Give an example. Different numbers of neutrons, same atomic number
Carbon – 12 Carbon – 14
5. The isotope
70
Zn has how many protons? 30 (70 is the mass number)
30
6. Write the correct oxidation number (charge) for each of the following.
sodium
___Na+1____
barium
___Ba+2_____
bromine
___Br-1____
sulfur
___S-2______
aluminum
___Al+3____
nitrogen
___N-3______
nitrate
___NO3-1__
hydroxide
___OH-1______
acetate
__C2H3O2-1__
sulfite
___SO3-2_____
7. In a balanced compound, the charge of the cation plus the charge of the anion should equal zero.
8. Ionic compounds are made up of a __metal__ and a __non-metal____ , and covalent compounds are
made up of two __non-metals__.
9. How many atoms are in the compound Pb(CrO4)2 ? 11 (1 + 2 + 8)
10. Lead (II) oxide is obtained by roasting galena, lead (II) sulfide, in air.
2 PbS (s)
+ 3 O2 (g)
2 PbO (s)
+
2 SO2 (g)
a. Balance the equation and determine the theoretical yield of PbO if 200.0 g PbS is heated.
200 gPbS
1mol PbS
2 mol PbO
223.3 g PbO
= 186.57 g PbO
239.27 g PbS
2 mol PbS
1 mol PbO
b. What is the percent yield if 170.0 g PbO is obtained.
170.0 g PbO
x 100 = 91.12%
186.57 g PbO
11. Predict whether the following reactions will occur. If yes, finish the reaction by writing the products
and balancing the equation.
a. ____ Fe + __2_ HCl FeCl2 + H2
b. ____ CuO + ____ Ag NR
c.
_2__ Al + _3__ H2SO4 Al2(SO4)3 + 3H2
d. ____ MgBr2 + ____ Fe NR
12. Work the following problems.
a. Calculate the mass of 3.57 moles of aluminum. (mole to mass)
3.57 mol Al 26.98 g Al
= 96.32 g Al
1 mol Al
b. How many moles are in 25.0 g of Fe2O3? (mass to mole)
25.0 g Fe2O3 1 mol Fe2O3 = 0.16 mol Fe2O3
159.7 g Fe2O3
c. Calculate the number atoms in 2.50 moles of Zinc. (moles to particles)
2.50 mol Zn 6.02 x 1023 atoms Zn
= 1.51 x 1024 atoms Zn
1 mol Zn
d. Determine the number of moles for 3.58 x 1023 formula units ZnCl2? (particles to moles)
3.58 x 1023 formula units ZnCl2
1 mol ZnCl2
= 0.59 mol ZnCl2
6.02 x 1023 formula units ZnCl2
13. List 5 properties of bases.
(1) Bitter
(2) OH(3) Slippery
(4) pH 7.1 -- 14
(5) Red Litmus turns Blue add caustic
14. List 5 properties of acids.
(1) sour
(2) H+
(3) pH 1-6.9
(4) Blue Litmus turns Red
(5) Corrosive to metal
15. When an acid reacts with a base, a _salt_ and __water__ form.
16. Show the general equation for a neutralization reaction then give an example of one that doesn’t
include hydrochloric acid or sodium hydroxide. Acid + base salt + water
Mg(OH)2 + 2HBr MgBr2 + 2H2O
CsOH + HBr CsBr + H2O
17. What is the pH and pOH of a solution if the [OH-]= 1.0 x 10-3. Is this an acid, a base, or neutral?
pOH = - (log 1.0 + log 10-3)
pOH = -(0 + -3)
pOH = 3
pH = 11
Basic
18. What is the pH and pOH of a solution if the [H+]= 4.0 x 10-6. Is this an acid, a base, or neutral?
pH = -(log 4 + log 10-6)
pH = - (.60 + -6)
pH = 5.4
pOH = 8.6
Acidic
19. What is the charge on the hydronium ion? H+1
20. Define pH, and explain the pH scale (see page 610).
pH is the negative logarithm of the hydrogen ion concentration (percent hydrogen)
used to determine acids & bases
scale from 1-14 (below 7 = acid, 7 = neutral; above 7= base)
21. Balance the following equations, label the reactants (left of arrow) and products (right of arrow),
then name the type of reaction.
a. 2NaOH(aq) + CaBr2 (aq) Ca(OH)2(s) + 2NaBr(aq) -- double replacement
b. 2C4H10(g) +
c. 3Fe(s) +
d. H2(g) +
13O2(g) 8CO2(g)
4H2O(l) F2(g)
Fe3O4(s)
+
10H2O(g) -- combustion
+ 4H2(g) -- single replacement
2HF(g) -- synthesis
22. Predict the Products for the following reactions – for double replacement reactions be able to identify
soluble and insoluble substances using the solubility chart, for single replacement reactions you must
use the activity series to identify if the reaction will occur,
a. Combustion of C8H18
2C8H18 + 25O2 16 CO2 + 18H2O
b. Decomposition of magnesium bromide Mg + Br2 Mg
+
Br2
c. Synthesis reaction between hydrogen and iodine H2 + I2 2HI
d. Single replacement reactions:
i. Nickel + magnesium chloride Ni + MgCl2 NR
ii. Calcium + copper (II) bromide Ca + CuBr2 CaBr2 + Cu
e. Double replacement reaction sodium phosphate + manganese (II) chloride 2Na3PO4
+ 3MnCl2 Mn3(PO4)2 (↓) + 6NaCl (aq)
23. List the 7 diatomic elements. Br2 I2 N2 Cl2 H2 O2 F2
24. The calculation of quantities in a chemical reaction is known as __stoichiometry__.
25. List 5 indicators that tell you when a chemical reaction has occurred.
(1) heat (temperature change)
(2) precipitate
(3) color change
(4) different odor
(5) light
26. Write chemical equations for the following, then balance the equations.
a. hydrogen(g) + bromine(g) hydrogen bromide(g)
H2 + Br2 2HBr
b. potassium chlorate(s) potassium chloride(s) + oxygen(g)
2KClO3 (s) 2KCl (s) + 3O2 (g)
c. Bubbling hydrogen sulfide gas through manganese(II) chloride dissolved in water results in the
formation of the precipitate manganese(II) sulfide and hydrochloric acid.
H2S (g) + MnCl2 (aq) MnS (s) + 2HCl (aq)
d. Chloroform (CHCl3), an important solvent, is produced by a reaction between methane and
chlorine. Given the following balanced equation, tell how many grams CH4 is needed to produce
50.0 g CHCl3? (stoichiometric mass to mass)
CH4(g) + 3Cl2(g) CHCl3(g) + 3HCl(g)
50 gCHCl3
1 mol CHCl3
119.37 g CHCl3
1 mol CH4
1 mol CHCl3
16.043 g CH4 = 6.72 g CH4
1 mol CH4
27. 50°C is equal to ___50 + 273 = 323 Kelvin.
28. When measuring pressure,
____760___ torr = ___1_____ atm = ___760__ mm Hg = 101.3 KPa
29. When the temperature of a gas decreases, what effect does this have on the volume of the gas?
Charles’ Law – temperature and volume are directly related, as temp decreases volume decreases
30. A gas at 89°C occupies a volume of 0.67 L. At what Celsius temperature will the volume increases to
1.12L? (Charles’s law) p. 424
V1 = V2
.67 L = 1.12 L
T2 = 605.13 K
T2 = 605.13 – 273 = 332.13oC
T1
T2
362 K
T2
31. The pressure of a sample of helium in a 1.00-L container is 0.988 atm. What is the new pressure if the
sample is placed in a 2.00-L container? (Boyle’s law) p. 422
V1P1 = V2P2
1.00 L x 0.988 atm = 2.00 L x P2
P2 = .499 atm
32. The air in a dry, sealed 2-L soda bottle has a pressure of 0.998 atm at sealevel at a temperature of
34.0°C. What will be its pressure if it is brought to a higher altitude where the temperature is only
23.0°C? (combined gas law) p.428
P1V1 = P2V2
.998 atm x 2 L = P2 x 2 L
P2 = .962 atm
T1
T2
307 K
296 K
33. The pressure in an automobile tire is 1.88 atm at 25.0°C. What will be the pressure if the temperature
warms up to 37.0°C? (Gay-Lussac’s law) p. 426
P1 = P2
1.88 atm =
P2
P2 = 1.96 atm
T1
T2
298 K
310 K
34. Determine the density of chlorine gas at 22.0°C and 1.00 atm of pressure. (ideal gas law) p. 434
D = MP
RT
D = 70.9 g/mol x 1 atm = 2.93 g/L
0.0821 L atm x 295 K
mol K
35. What does the ideal gas law allow a scientist to calculate that the other gas laws do not?
Number of moles, density and molar mass if pressure, volume and temperature are known
36. Standard temperature and pressure (STP) are equal to ___1atm___ and ___0oC_____.
37. Define coefficient, superscript and subscript.
Coefficient: In a chemical equation, the number written in front of the formula; tells the smallest
number of particles of the substance involved in the reaction.
Superscript: exponent
Subscript: identifies the number of atoms of an element in a compound or formula (little number to
the right of the atom)
38. What is the molarity of 1.5 L of solution in which 6.0 moles of potassium chloride is dissolved?
Molarity = moles
=
6.0 mol
= 4 mol
Liter
1.5 L
L
39. List the factors that affect solubility. Size of particles, agitation, temperature & concentration
(solubility of gases is affected by pressure and temperature – dissolve more easily at high pressure
and /or low temperature)
40. Draw the Lewis dot structure for sodium, calcium, carbon, oxygen and bromine.
41. Convert 8.00 liters of H2O to moles. (volume to mole)
8.00 L 1 mol = .357 mol H2O
22.4 L
42. Where would you look to obtain mole ratios? (multiple choice) D
a. the periodic table
b. the molar masses
c. the polyatomic ion sheet
d. a balanced chemical equation
43. Calculate molar mass for the following.
a. AlBr3
26.98 + 3(79.90) = 266.68 g/mol
b. H2O2
c. H3PO4
2(1.01) + 2(16) = 35.03 g/mol
3(1.01) + 30.97 + 4(16) = 98 g/mol
44. Caffeine, a stimulant found in coffee, has the chemical formula C8H10N4O2. Determine the percent
composition of caffeine.
8(12.01)+10(1.01)+4(14.01)+2(16)=194.2 g/mol
96.08 x 100 = 49.47% C
194.2
10.1 x 100 = 5.19% H
194.2
56.04 x 100 = 28.86% N
194.2
32 x 100 = 16.48% O
194.2
45. Compare molecular and empirical formulas.
Molecular – actual atom combination within a formula
Empirical – lowest whole number ratio of atoms of a formula
46. Determine the molecular formula for ibuprofen, a common headache remedy. Analysis of ibuprofen
yields a molar mass of 206 g/mol and a percent composition of 75.7% C, 8.80% H an d15.5% O. (find
the empirical formula first)
75.7 g C = 6.3 ÷ .96 = 6.56 x 2 = 13
12.01
8.80 g H = 8.71 ÷ .96 = 9.07 = 9 x 2 = 18
1.01
Empirical Formula C13H18O2
15.5 g O = .96 ÷ .96 = 1 x 2 = 2
16
molar mass of Empirical Formula = 206.31 g/mol
n = 206 g/mol
= .998 = 1
206.31 g/mol
1 (C13H18O2) = C13H18O2
47. Which group of elements on the periodic table is most likely to donate one electron? Alkali Metals
(group 1)
48. Which other elements on the periodic table are most similar to chlorine in their bonding
characteristics? All group 17 nonmetals
49. What is the value of Avogadro’s number? 6.02 x 1023
50. What are the rules for multiplying and dividing with significant figures?
Multiply and dividing significant figures – keep smallest value of all factors
51. Define:
a. Hydrate: a compound that has a specific number of water molecules bound at its atoms
b. Precipitate: a solid produced during a chemical reaction in a solution
c. Reactant: the starting substance in a chemical reaction
d. Product: a substance produced during a chemical reaction
52. Use the chemical equation to answer the questions.
2CH4(g) + S8(s) 2CS2(l) + 4H2S(g)
a) Calculate the mol CS2 produced when 1.50 mol S8 is used. (stoichiometric mole to mole)
1.5 mol S8
2 mol CS2
1 mol S8
=
3 mol CS2
b) How many grams of sulfur would you need if you had 24.0 grams of methane? (stoichiometric
mass to mass)
24 g CH4
1 mol CH4
16.05 g CH4
1 mol S8
2 mol CH4
c) What is the ratio of reactants to products?
2CH4/2CS2
2CH4/4H2S
1S8/2CS2
256.56 g S8
1 mol S8
= 191.82g S8
1S8/4H2S
53. How many atoms (molecules), how much volume and how many grams does one mole of chlorine gas
have?
1 mol Cl2 = 22.4 Liters
1 mol Cl2 = 6.02 x 1023 molecules
1 mol Cl2 = 70.90 grams
54. State the Law of Conservation of Mass.
States that mass is neither created nor destroyed in any process but is conserved
55. Compare covalent and ionic bonding.
Covalent: results from the sharing of valence electrons; between 2 non-metals
Ionic: electrostatic force that holds oppositely charged particles together in an ionic compound,
formed between metal and non-metal, transfer of electrons
56. What is the difference between physical and nuclear chemistry?
Physical Chemistry – studies the behavior and changes of matter and the related energy changes
(deals with how substances bond)
Nuclear Chemistry – involves the nucleus, structure of the atomic nuclei and the changes they
undergo
57. Compare fission and fusion. (define and identify uses)
Fission: the splitting of a nucleus into fragments
Fusion: the combining of atomic nuclei
58. Compare alpha, beta and gamma particles.
Alpha: a particle with twp protons and two neutrons, with a 2+ charge; is equivalent to a helium -4
nucleus, can be represented by x, and is emitted during radioactive decay.
Beta: a high-speed electron with a 1- charge that is emitted during radioactive decay.
Gamma: high energy radiation that has no electrical charge and no mass, is not deflected by electric
or magnetic fields, usually accompanies alpha and beta radiation, accounts for most energy lost
during radioactive decay
59. Define radioactivity.
The process in which some substances spontaneously emit radiation.
60. How much of a 100.0 g sample of 198Au is left after 8.10 days if its half-life is 2.70 days?
Sample Size
Time
# of ½ lives
100 gram
0 days
0 – ½ lives
50 gram
2.7 days
1 – ½ lives
25 gram
5.4 days
2 – ½ lives
12.5 gram
8.1 days
3 – ½ lives
Answer – 12. 5 grams
61. Describe a saturated, unsaturated, and supersaturated solution.
a. Saturated: Contains the maximum amount of dissolved solute for a given amount of solvent at
a specific temperature and pressure
b. Unsaturated: contains lee dissolved solute for a given temperature and pressure than a
saturated solution; has further capacity to hold more solute
c. Supersaturated: contains more dissolved solute than a saturated solution at the same
temperature
Use the following graph to answer the questions below.
62. What are the solubilities of the following solutes at 60oCelcius?
a. KI
-- 230 g/100 cm3 water
b. NaNO3 -- 123 g/100 cm3 water
c. KClO3 -- 27 g/100 cm3 water
63. What type of solution is prepared when 160 g of KI is added to 100 grams of water at 15oC?
supersaturated
64. Which substance is most soluble at 45oC? KI
65. Which substance is least soluble at 30oC? KClO3
Know all conversion factors used in mole calculations.