Problems: Using your periodic table, determine the following:
_____17___7. atomic number of chlorine
______56
8. number of protons in barium
_____20
9. number of electrons in calcium
_____50_____10. number of neutrons in strontium
31
_____15_____11. mass number of
15
P
59
_____31_____12. number of neutrons in
28 Ni
13
_____6_____13. number of protons in an isotope of
6C
Determine the electron configuration notation for the following;
41. Na+__1s2 2s2 2p6_________________42. B________1s2 2s2 2p1___________
43. Ne__1s2 2s2 2p6___________________44. O_____1s2 2s2 2p4_______________
45. I -1___[Kr] 5s2 4d10 5p6
OR [Xe]
Why is the ionization energy of fluorine higher than that of magnesium?___The electrons around F are
close to the nucleus and held more tightly by the protons than in Mg and therefore harder to loose The last
2 electrons in Mg have less force acting because they are in the 3rd energy level which is further away
making them easier to remove.
Explain why removing an electron from a neutral sodium atom would cause it to become a positive
ion.___A neutral sodium atom has 11 protons and 11 electrons. When an electron is lost, there are 10
electrons and 11 protons therefore one extra positive!
What is isoelectronic with the following ions? Cl -1, Mg+2, Al+3 Argon
How does one determine whether a molecule is polar, nonpolar or ionic?_% ionic character
Determine the molar mass and percent composition of each element in the following compounds:
1 hydrazine, N2H2
__93%____% N
_____7%___% H
2. glucose C6 H12 O6
____40% C __ 6.7 __ %H _____53.3_ % O
3. potassium permanganate KMnO4 ____24.74_ % K __34.76____% Mn ___59.5__% O
4. Determine the empirical formula for a compound with 27.7 g of sodium, 22.95 g of silicon,
39.3 g of oxygen.
Na3Si2O6
5. Determine the empirical formula of a compound with 77.5% silver, 7.4% phosphorous and 15.3 %
oxygen.
Ag3PO4
6. A 6.00 gram sample of a hydrate of MgSO4 was heated and only 2.93 g of the anhydrous salt
remained. What percentage water was in the hydrate?
51.17%
7. What is the percentage water in Ni(NO3)2•6H2O?
37.15%
8. An 8.00 gram sample of CoCl2•nH2O is heated and 4.37 g of anhydrous salt remains.
What is the value of “n”?
n=6
Matching:
_D________9. left of the arrow in a reaction
A. double replacement
_____E____10. CaO + H2O → Ca(OH)2
B. decomposition
_____F____11. Cl2 + 2KBr → 2 KCl + Br2
C. products
______A___12. AB + XY → AY + XB
D. reactants
_____B____13. FeS → Fe + S
E. composition
F. single replacement
Problems:
Complete the word equation and write a balanced chemical equation for the following reactants:
14. aluminum chloride and magnesium produce___aluminum + magnesium chloride
2 AlCl3 + 3 Mg ---------> 3 MgCl2 + 2 Al
15. barium sulfate and cobalt (II) chloride forms __barium chloride + cobalt II sulfate
_________BaSO4 + CoCl2 ---------> BaCl2 + CoSO4
16. hydrogen and chlorine yields__hydrogen chloride (or hydrochloric acid)
_____________H2 + Cl2 -------------> 2 HCl
___________________
19. calcium chlorate makes__calcium chloride + oxygen
____________ Ca(ClO3)2 ----------------> CaCl2 + 3 O2
20. zinc and hydrogen sulfate produces____zinc sulfate and hydrogen
_______Zn + H2SO4 ---------> ZnSO4 + H2
21. sodium chloride and fluorine produces__sodium fluoride + chlorine
____2_NaCl + F2 ----------> 2 NaF + Cl2
Molarity problems using grams:
1. How many grams of K2CrO4 are needed to make 50.0 mL of a 0.10 molar solution? 0.97 g
2. What is the molarity of a solution in which 25.0 grams of NaCl is dissolved in 100.0 mL of
solution?
4.28 M
3. How many grams of NaCl are needed to make a O.50 M solution with 100.0 mL of solution?
2.92 grams
4. How many milliliters of a 0.500 M solution can be prepared from 3.45 grams of KOH?
123 ml
5. A student is to determine the molarity of a solution of sulfuric acid by titrating 25.00 ml of the acid
with 0.485 M potassium hydroxide in each of 2 trials. Complete the table. SHOW YOUR WORK.
2 KOH + H2SO4 ------------> K2SO4 + 2 H2O
DATA TABLE:
BASE
KOH
Trial 1
Trial 2
.485 M (.02408) = 0.01168 mol KOH
Final volume (mL)
_24.58_
_33.25_
0.01168 KOH x 1 H2SO4 = .00584 H2SO4
Initial volume (mL)
_0.50_
__1.55_
2 KOH
Volume used (mL)
_24.08
_31.7
Molarity of H2SO4
_0.2336
_0.307
.00584 H2SO4 / .025 L = 0.2336 M
1. How many grams of HgCl2 are needed to prepare 200.0 mL of 0.450 M solution? 24.43 g
2. How many milliliters of a 0.050 M solution can be prepared form 16.5 g of sodium chloride?
5.65 L
3. How many grams of calcium hydroxide are needed to prepare 300.0 mL of a 0.115 M solution?
2.55 g
4. How many milliliters of a 0.650 M solution can be prepared from 5.12 grams of Mg(OH)2?
136 ml
5. What is the molarity of a solution if 15.0 grams of NaOH are dissolved in 1400 mL of solution.
0.268 M
6. If 15.0 mL of a 0.0250 M solution of sulfuric acid is required to neutralize 10.0 mL of, magnesium
hydroxide what is the molarity of the magnesium hydroxide solution?
0.0375 M
See pencast 1
7. In a titration experiment, a 12.5 mL sample of 0.0175 M barium hydroxide just neutralized
14.5 mL of sulfuric acid solution. Calculate the molarity of the sulfuric acid solution.
0.0151 M
8. If 13.4 mL of 0.0230 M phosphoric acid is required to neutralize 17.0 mL of manganese II
hydroxide in a titration experiment, determine the molarity of the manganese hydroxide solution.
See Pencast 1
0.0272 M
9. Oxygen was discovered by Joseph Priestley in 1774 when he decomposed mercury (II) oxide to its
simplest elements by heating it. How many grams of mercury (II) oxide are needed to produce 125.0 g
of oxygen?
2 HgO ----> 2 Hg + O2
1692 g of O2
10. a. Iron reacts with oxygen to produce iron (III) oxide. If 84.9 g of iron is used, what mass of
oxygen is needed for the complete reaction ?
36.48 g
4 Fe + 3 O2 -----> 2 Fe2O3
b. In the above reaction, what mass of iron is required to produce 11.7 g of iron III oxide?
8.18 g
11. (a) Potassium chlorate decomposes to potassium chloride and oxygen. Given 8.20 g of potassium
chlorate, calculate the mass of potassium chloride produced.
4.99 g
See pencast 2
(b) In the above reaction, what is the mass of O2 produced?
3.21 g
12. (a) Write the combustion reaction for ethane, C2H6. If 109.0 g of ethane reacts, how much
oxygen must be used?
(b) In the above reaction, find the mass of carbon dioxide produced.
(c) Find the amount of water produced in the above combustion reaction.
(a) 2 C2H6 + 7 O2 ---------> 4 CO2 + 6 H2O; (b) 319.73 g ; (c) 196.2 g
13. When iron and steam react together, they form black iron oxide, Fe3O4, and hydrogen gas. When
36.0 g of water react with 176.0 g of iron how many grams of Fe3O4 are produced? 115.78 g
14. If 15.0 g of oxygen and 15.0 g of aluminum react, how many grams of aluminum oxide are
produced? See pencast 2
28.34 g
4 Al + 3 O2 -----------------> 2 Al2O3
15. In the problem number 14 above, which element was in excess and by how much? O; 1.66 g
percent yield = actual yield
x 100
theoretical yield
1. . Methanol can be produced through the reaction of carbon monoxide and hydrogen gas in the
presence of a catalyst. The equation is :
See Pencast 2
CO (g) + 2 H2 (g) --------------->
CH3OH
If 75.0 grams of CO reacts to produce 68.4 g of CH3OH, what is the percent yield of methanol?
79.8%
2. In the reaction below, 9.85 g of Fe produces 11.7 grams of Fe2O3, what
is the percent yield? 4 Fe + 3 O2 ---------------> 2 Fe2O3
83.6%
3. Old oil paintings can be cleaned by the reaction of hydrogen peroxide with
lead (II) sulfide by the reaction: PbS + 4 H2O2 -------> PbSO4 + 4 H2O2
What is the theoretical yield of PbSO4 based on 0.80 g of H2O2?
1.78 grams
3. Elemental iron can be recovered from iron (III) oxide ore by reaction with carbon monoxide.
Fe2O3 + 3 CO --------> 3 CO2 + 2 Fe
a. When 145.0 g of iron (III) oxide reacts with 95.0 g of carbon monoxide, how much iron will form?
See Pencast 3
101.42 g
b. Assume that 93.0 g of iron is produced in the reaction above. What is the percent yield of this
reaction?
91.7%
Colligative properties
1. What mass of water is needed to dissolve 34.8 g of copper(II) sulfate in order
to prepare a 0.521 m solution?
0.4186 kg
2. Calculate the freezing point of a solution made from 32.7 g of propane, C3H8, dissolved in 137.0 g
of benzene, C6H6. The freezing point of benzene is 5.50° C and its Kf is 5.12° C/m. 22.27oC
See pencast 4
3. Calculate the boiling point of a solution made from 227 g of MgCl2 dissolved in 700. g of water.
What is the boiling point of the solution? Kb = 0.512° C/m.
101.7o C (in reality, it
o
would be closer to 105.2 C. WHY?)
4. A solution contains 21.6 g of a nonelectrolyte and 175 g of water. The water freezes at -7.18° C
and Kf = 1.86° C/m. Is the nonelectrolyte CH3OH or C2H5OH?
CH3OH
See pencast 4
For each of the atoms listed below, write the nuclear reaction.
256
1. 256103 Lr undergoes alpha decay
103 Lr -------------->
2.
6
3.
175
93
Np undergoes beta bombardment
4.
211
79
Au undergoes alpha bombardment
2
He undergoes beta decay
6
2
He --------->
175
93
211
79
0
-1
Np +
Au +
4
2
4
2
He +
e +
0
-1
6
3
252
101
Md
Li
e ------------->
He --------->
215
81
175
92
U
Tl
1. An isotope of cesium (cesium-137) has a half-life of 30 years. If 1.0 mg of cesium-137
disintegrates over a period of 90 years, how many mg of cesium-137 would remain? 0.125 mg
2. .A 2.5 gram sample of an isotope of strontium-90 was formed in a 1960 explosion of an atomic
bomb at Johnson Island in the Pacific Test Site. The half-life of strontium-90 is 28 years. In what
year will only 0.625 grams of this strontium-90 remain?
2016
3. Thallium-201 has a half-life of 73 hours. If 4.0 mg of thallium-201 disintegrates over a period of
6.0 days and 2 hours, how many mg of thallium-201 will remain?
2.0 mg
4. Sodium-25 was to be used in an experiment, but it took 3.0 minutes to get the sodium from the
reactor to the laboratory. If 5.0 mg of sodium-25 was removed from the reactor, how many mg
of sodium-25 were placed in the reaction vessel 3.0 minutes later if the half-life of sodium-25 is
60 seconds?
0.625 mg
5. Selenium-83 has a half-life of 25.0 minutes. How many minutes would it take for a 10.0 mg
sample to decay and have only 1.25 mg of it remain? 75.0 min
6. The half-life of Po-218 is three minutes. How much of a 2.0 gram sample remains after 15
minutes? Suppose you wanted to buy some of this isotope, and it required half an hour for it to
reach you. How much should you order if you need to use 0.10 gram of this material?
0.0625 g; 102.4 g
7. Explain where a beta particle originates and what happens during beta bombardment.
8. What is the difference between fission and fusion?
9. What is the difference between a strong and weak acid?
10. Explain why the transition elements do not vary much radius.
11. What is the purpose of an antacid tablet? While shopping or if you have some at your home, look
at the active ingredient in any type of antacid tablet. Record the mass and compound name. (a) Write
the formula for that active ingredient then write the equation for the reaction between it and the
hydrochloric acid in your stomach. (b) Using the mass of the active ingredient, determine the amount
of hydrochloric acid that one tablet can neutralize.
12. Which compound lowers the freezing point of water more: 1 mole of barium chloride or 1 mole of
nitrous acid? Justify your answer.