Chemistry: 1001 Practice Problems For Dummies®
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Whether you’re taking your first chemistry course, you’re taking your last chemistry course, or you just need a little practice before taking a test that contains chemistry questions (like a nursing, pre-med, or teacher certification test), doing problems is a fine way to prepare.
The 1,001 practice questions in this book cover topics that you might encounter in a high school chemistry course, an introductory college chemistry course, the first semester of a general chemistry course for science majors, or a general science test for entry into a pre-professional program. The types of questions found here are similar to the ones you may see on homework assignments, quizzes, practice tests, or actual tests.
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After you use this book and identify the areas you feel need extra effort, you can start studying on your own and then come back here to answer the questions again to measure your improvement. For example, if your knowledge of molarity is a little hazy (or nonexistent), try reviewing the molar calculations in Chapter 10. Check your answers and jot down notes or questions you may have. Then research, say, how solution concentration is expressed using molarity or which biology applications might use molarity. You can look for resources at your local library or online, or you can ask a friend, coworker, or professor to coach you if they seem to spend a lot of time in the lab. You can also check out the For Dummies series for books about many of the topics covered in chemistry. Head to www.dummies.com to see the many books and articles that can help you in your studies.
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Part 1
IN THIS PART …
One thousand one chemistry problems — that’s a lot of chemistry practice. Hundreds of our former students have persevered through what we’re sure they felt was even more than that. Here are the general types of questions you’ll be dealing with:
Chapter 1
Many aspects of chemistry are quantitative, and you use units to measure these quantities. In many cases, you have to convert from one unit to another. Most people in the United States initially learn the English system of units, but most chemists use the Système international d’unités (the SI system), derived from the older metric system. Unit conversions relate these two systems. Dimensional analysis provides a systematic means to not only perform these conversions but also to work many of the other problems in this book. Dimensional analysis lets the units solve the problem for you.
In this chapter, you work with units and unit conversions in the following ways:
Don’t let common mistakes trip you up; remember the following when working on units and unit conversions:
1–10 Answer the questions on metric prefixes and metric units used in the laboratory.
1. What is a common metric unit of mass used in the laboratory?
2. What is a common metric unit of length used for measuring small objects in the laboratory?
3. What is a common metric unit of volume used in the laboratory?
4. What is a common metric unit of pressure used in the laboratory?
5. What is a common metric unit of energy?
6. What is the metric prefix that represents 1,000?
7. What is the metric prefix that represents ?
8. What is the metric prefix that represents ?
9. What is the metric prefix that represents 10–9?
10. What is the metric prefix that represents 106?
11–20 Choose appropriate metric or English units for measuring everyday objects.
11. Which metric unit is most appropriate for expressing the mass of an adult human?
12. Which metric unit is most appropriate for recording the volume of a child’s wooden block?
13. Which metric unit would a scientist use to measure the temperature on a warm autumn day?
14. Which metric unit is most often used for small doses of solid medications?
15. Which SI base unit is named after a person?
16. Which English unit is most similar in volume to a liter?
17. Which English unit is most similar in length to a meter?
18. How many fluid ounces are in a cup?
19. An Olympic swimmer competes in the 100-meter freestyle. What is the comparable English unit?
20. If a wooden board’s width is 6 in., what is an appropriate metric unit to express this width?
21–32 Complete the conversion between metric units.
21. How many milligrams are in 1 dg?
22. How many deciliters are in 1 L?
23. How many kilometers are in 1 m?
24. How many centimeters are in 1 m?
25. How many grams are in 1 hg?
26. How many milliliters are in 2.5 daL?
27. How many centigrams are in 49 kg?
28. How many gigawatts are in 370,000 W?
29. How many micrograms are in 0.126 Mg?
30. How many kilometers are in 80 pm?
31. How many cubic meters are in 2 L?
32. How many milliliters are in 0.64 m3?
33–59 Convert between metric and English units.
33. How many miles are in 35 km?
34. How many inches are in 0.20 cm?
35. How many yards are in 202 m?
36. How many pounds are in 58 kg?
37. How many quarts are in 7.54 L?
38. How many centimeters are in 0.087 in.?
39. How many kilometers are in 463 mi.?
40. How many grams are in 91 lb.?
41. How many liters are in 525 gal.?
42. How many atmospheres are in 44 psi?
43. How many cups are in 2.00 L?
44. How many pounds are in 164 hg?
45. How many gallons are in 587 mL?
46. How many centimeters are in 6.02 mi.?
47. How many decigrams are in 225 lb.?
48. How many milliliters are in 6.8 qt.?
49. How many centimeters are in 15.3 ft.?
50. How many liters are in 99 pt.?
51. How many kilograms are in 1.00 short ton?
52. How many centimeters are in 6.04 yd.?
53. How many cups are in 15 cc?
54. How many millimeters are in 1,760 yd.?
55. How many pints are in 250 hL?
56. How many grams are in 0.35 slugs?
57. How many kilometers are in 9,999 in.?
58. How many ounces are in 0.734 kg?
59. How many microliters are in 55 oz.?
60–75 Solve the word problem using a setup similar to those used in unit conversions.
60. How many dozen eggs are in 17,981 eggs?
61. How many years are in 6,250 days?
62. How many weeks are in 2.5 centuries?
63. If the average penny has a mass of 3.16 g, what is the dollar value of 1.00 short ton of pennies?
64. If an athlete runs the 100-yard dash in 10.0 s, how long will it take for the athlete to run 400 m?
65. You’re planning a party and need enough soda for 60 guests. How many liters will you need, assuming each guest drinks 10 fl. oz. of soda?
66. You plan to serve sub sandwiches at a party. How many 6.0-foot subs will you need to feed the 60 guests if each person eats a 25.4-cm length of sandwich?
67. A textbook measures 230 mm long, 274 mm wide, and 60.0 mm thick. What is the volume in cubic centimeters?
68. A textbook measures 230 mm long, 274 mm wide, and 60.0 mm thick. What is the surface area of the front cover in square meters?
69. A hallway measures 10.0 ft. by 5.0 ft. How many square tiles, measuring 10.0 in. on each side, are necessary to cover the floor?
70. If a car is going 20 mph through a school zone, how many centimeters per minute is it traveling?
71. A solid sphere made of pure gold has a volume of 2.0 L. What is the mass of the sphere, in pounds, if 1.00 cm3 of gold has a mass of 19.3 g?
72. How many minutes does it take a horse to run 12 furlongs at 35.3 mph?
73. If a pitcher throws a 96-mph fastball, how many seconds will it take to travel the 60.5 ft. from the pitcher’s mound to home plate?
74. Pure gold can be made into extremely thin sheets called gold leaf. Suppose that 25 kg of gold is made into gold leaf having a surface area of 1,810 m2. How thick is the gold leaf in millimeters? The density of gold is 19.3 g/cm3.
75. Radio waves travel at 300,000,000 m/s. If you asked a question of someone who was on the moon, 239,000 mi. from the Earth, what is the minimum time that you would have to wait for a reply?
Chapter 2
Scientific notation allows you to write very large and very small numbers, which are common in chemistry, in a simplified manner. Many chemical experiments involve very precise measurements. The significant figures are an indication of the precision of these measurements. In calculations involving more than one measurement, you need to maintain the precision inherent in the significant figures.
In this chapter, you work with scientific notation and significant figures in the following ways:
Remember the following when working on scientific notation and significant figures:
76–80 Express the given number in scientific notation.
76. 876
77. 4,000,001
78. 0.000510
79. 900 × 104
80. 10
81–85 Convert the given number to nonscientific notation (regular decimal form).
81. 2.00 × 102
82. 9 × 10–2
83. 4.7952 × 103
84. 1.64 × 10–5
85. 0.83 × 10–1
86–105 Complete the calculations and record your answer in scientific notation. (If you use a calculator, choose a mode that doesn’t put the numbers in scientific notation for you.)
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106–115 Indicate how many significant figures (significant digits) are in the given number.
106. 343
107. 0.4592
108. 705,204
109. 0.0075
110. 248,000
111. 9,400,300
112. 1.0070
113. 3,000,000.0
114. 0.0040800
115. 0.870
116–135 Complete the calculation and express your answer using the correct number of significant figures.
116.
117.
118.
119.
120.
121.
122.
123.
124.
125.
126.
127.
128.
129.
130.
131.
132.
133.
134.
135.
Chapter 3
Chemists deal with matter. Matter occurs in many forms with certain observable properties. One easily observable property of matter is density, which is the mass of a sample of matter divided by its volume. It’s possible to alter matter either physically or chemically. All alterations involve energy.
In this chapter, you work with matter and energy in the following ways:
Remember the following when working on matter and energy:
136–143 Check your understanding of phases of matter and phase changes.
136. Which phase of matter doesn’t have a definite shape or a definite volume under normal conditions?
137. Which phase of matter has a definite shape and a definite volume?
138. Which phase of matter has a definite volume but takes the shape of the container that it’s in?
139. When matter changes from a liquid to a solid, which phase change is it going through?
140. When matter changes from a gas to a liquid, which phase change is it going through?
141. When matter changes from a liquid to a gas, which phase change is it going through?
142. When matter changes from a solid to a gas without becoming a liquid in between, which phase change is it going through?
143. When matter changes from a gas to a solid without becoming a liquid in between, which phase change is it going through?
144–152 Classify each type of matter as a pure substance or mixture. Then classify each pure substance as an element or compound and each mixture as homogeneous or heterogeneous.
144. Gold
145. Table sugar
146. Fresh air
147. Oxygen
148. Vegetable soup
149. Fruit salad
150. Calcium
151. Concrete
152. Smog
153–165 Check your understanding of the properties of matter.
153. Which type of property of matter doesn’t depend on the amount of the substance that’s present?
154. Which type of change involves a change in the form of a substance?
155. Which type of change involves a change in the identity of a substance?
156. Which type of property of matter depends on exactly how much of the substance is present?
157. Density is a(n) _______________ (chemical/extensive physical/intensive physical) property.
158. Length is a(n) _______________ (chemical/extensive physical/intensive physical) property.
159. Color is a(n) _______________ (chemical/extensive physical/intensive physical) property.
160. Flammability is a(n) ___________ (chemical/extensive physical/intensive physical) property.
161. Mass is a(n) _______________ (chemical/extensive physical/intensive physical) property.
162. Odor is a(n) _______________ (chemical/extensive physical/intensive physical) property.
163. Ductility is a(n) _______________ (chemical/extensive physical/intensive physical) property.
164. Electrical conductivity is a(n) _______________ (chemical/extensive physical/intensive physical) property.
165. Solubility is a(n) _______________ (chemical/extensive physical/intensive physical) property.
166–174 Perform the density calculations. Be sure to round your answers to the correct number of significant figures. (See Chapter2 for significant figure problems.)
166. In grams per cubic centimeter, what is the density of a substance with a mass of 57.5 g and a volume of 5.0 cm3?
167. A 25.0-mL sample of a liquid has a mass of 22.1 g. What is the liquid’s density in grams per milliliter?
168. The mass of 2.00 m3 of a gas is 3,960 g. What is the density of this gas in kilograms per cubic meter?
169. What is the mass, in grams, of 0.200 L of a saltwater solution with a density of 1.2 g/mL?
170. Aluminum is a metal that has a density of 2.7 g/cm3. How many grams are in a solid cube of aluminum that measures 3.00 cm per side?
171. If a block has a length of 5.0 cm, a width of 3.0 cm, a height of 2.0 cm, and a mass of 120 g, what is the block’s density?
172. What is the mass, in kilograms, of 1.5 L of solid gold? Solid gold has a density of 19.3 g/cm3.
173. If a sample of gasoline has a mass of 77.0 g and a density of 0.71 g/mL, what is the volume of the gasoline in milliliters?
174. What is the length of one side of a metallic cube that has a density of 10.5 g/cm3 and a mass of 672 g?
175–190 Assess your understanding of energy and related calculations.
175. Which unit represents the amount of energy necessary to raise the temperature of 1 g of water by 1°C?
176. Which SI unit is used to express the heat content of a mole of a chemical?
177. Which unit is used to express the energy found in food?
178. A bucket on a ladder has __________ (kinetic/potential) energy, which is the energy of __________ (motion/position).
179. A rolling ball has __________ (kinetic/potential) energy, which is the energy of __________ (motion/position).
180. Fuels contain __________ (moving/stored) energy, which is __________ (kinetic/potential) energy.
181. How many kilocalories are in 25,970 J?
182. How many joules are in 3.1 × 108 kilocalories?
183. Average kinetic energy can be measured in what units?
184. If water is heated to 80.0°C, how many kelvins is that?
185. The melting point of sodium chloride is 1,074 K. What temperature is this in degrees Celsius?
186. Liquid oxygen boils at –183°C. How many degrees Fahrenheit is this?
187. Normal human body temperature is considered to be around 98.6°F. How many degrees Celsius is this?
188. Adding dry ice to acetone brings the temperature down to –78°C. What is this temperature in degrees Fahrenheit?
189. One summer day, the temperature was recorded as 113°F. How many kelvins is this?
190. Room temperature is about 300 K. How many degrees Fahrenheit is this?
Chapter 4
An atom consists of a nucleus surrounded by one or more electrons. Although the number of protons identifies the element, the electrons are the key to the chemistry. The arrangement of electrons in an atom influences the atom’s ability to gain, lose, or share electrons and therefore form compounds. Quantum numbers describe the arrangement of the electrons. Unstable atoms undergo nuclear decay to transform to stable atoms. Atoms may be broken apart by fission or joined by fusion.
In this chapter, you work with atoms and nuclear chemistry in the following ways:
Note: For access to the periodic table, see the Appendix.
Remember the following when working on atoms and nuclear chemistry:
191–219 Answer the question on isotopes and subatomic particles.
191. How many protons are in an atom of sodium?
192. How many electrons are in an atom of bromine?
193. How many electrons are in an atom of nickel?
194. How many protons are in an atom of radon?
195. How many neutrons are in an atom of isotope potassium-40?
196. How is the atomic number related to the number of protons in an atom?
197. How is the mass number of an atom related to the number of neutrons?
198. How many protons, electrons, and neutrons are in an atom of isotope copper-63?
199. An atom has a mass number of 14 and 6 electrons. How many protons and neutrons does it have?
200. An atom has 40 electrons and 51 neutrons. What is its mass number, and how many protons does it have?
201. What does the top number in isotope notation represent?
202. What does the bottom number in isotope notation represent?
203. How many protons and neutrons are in ?
204. How many protons and neutrons are in ?
205. What is the isotope notation for an atom of carbon-12?
206. What is the isotope notation for an atom of chlorine-37?
207. What is the name of ?
208. How does an ion differ from an atom of the same element with regard to the numbers of subatomic particles?
209. When two atoms or ions have the same number of electrons, they’re said to be __________.
210. When an ion has a positive charge, how do the numbers of subatomic particles differ?
211. When an ion has a negative charge, how do the numbers of subatomic particles differ?
212. How many protons and electrons does have?
213. How many protons and electrons does have?
214. How many protons and electrons does have?
215. How many protons and electrons does have?
216. What is the isotope notation for an ion of silver-109 with a charge of positive 1?
217. What is the isotope notation for an ion of sulfur-34 with a charge of negative 2?
218. How many protons, neutrons, and electrons are in ?
219. How many protons, neutrons, and electrons are in ?
220–234 Answer the questions on electrons and quantum mechanics.
220. What is the name of the premise that one electron fills each orbital in a subshell until all orbitals contain one electron and then electrons are added to fill in the second available spot in the subshell?
221. What rule or principle describes the order in which electrons fill orbitals?
222. What is the maximum number of electrons that can be in the f orbitals?
223. What is the maximum number of electrons that can be in the p orbitals?
224. What is the electron configuration of carbon?
225. What is the electron configuration of magnesium?
226. What is the electron configuration of argon?
227. What is the electron configuration of bromine?
228. What is the electron configuration of zirconium?
229. What is the expected electron configuration of plutonium?
230. Which quantum number describes the spin of the electron?
231. Which quantum number describes the average distance between the nucleus and the orbital?
232. Which quantum number describes how the various orbitals are oriented in space?
233. Which quantum number describes the shape of the orbital?
234. What are the possible values for the spin quantum number?
235–242 Answer the questions on average atomic mass.
235. The decimal numbers in the blocks of the periodic table represent the __________.
236. What is the average atomic mass of lithium that is 7.59% lithium-6 (mass of 6.0151 amu) and 92.41% lithium-7 (mass of 7.0160 amu)?
237. What is the average atomic mass of chlorine that is 75.78% chlorine-35 (mass of 34.96885 amu) and 24.22% chlorine-37 (mass of 36.9659 amu)?
238. What is the average atomic mass of magnesium, given the information in the following table?
|
Isotope |
Percent Abundance |
Atomic Mass (amu) |
|---|---|---|
|
78.99 |
23.985 | |
|
10.00 |
24.986 | |
|
11.01 |
25.983 |
239. What is the average atomic mass of potassium, given the information in the following table?
|
Isotope |
Percent Abundance |
Atomic Mass (amu) |
|---|---|---|
|
93.258 |
38.9637 | |
|
0.01170 |
39.9640 | |
|
6.7302 |
40.9618 |
240. What is the average atomic mass of iron, given the information in the following table?
|
Isotope |
Percent Abundance |
Atomic Mass (amu) |
|---|---|---|
|
5.845 |
53.9396 | |
|
91.754 |
55.9349 | |
|
2.119 |
56.9354 | |
|
0.282 |
57.9333 |
241. What is the average atomic mass of krypton, given the information in the following table?
|
Isotope |
Percent Abundance |
Atomic Mass (amu) |
|---|---|---|
|
0.350 |
77.9204 | |
|
2.28 |
79.9164 | |
|
11.58 |
81.9135 | |
|
11.49 |
82.9141 | |
|
57.00 |
83.9115 | |
|
17.30 |
85.9106 |
242. If the average atomic mass of boron is 10.81 amu, what is the percent abundance of boron-11 (mass of 11.009306 amu) if the only other isotope is boron-10 (mass of 10.012937 amu)?
243–252 Answer the question on aspects of nuclear reactions and nuclear decay.
243. What is the primary nuclear process that occurs in the sun?
244. In which nuclear process does a nucleus split into two or more smaller elements and possibly some extra neutrons?
245. What is it called when a helium nucleus is ejected from the nucleus of an atom during a nuclear reaction?
246. When a ray is a byproduct of a nuclear reaction, what nuclear process has occurred?
247. What is the isotope (nuclear) notation for a particle that is produced from beta decay?
248. A particle is a product of which nuclear reaction?
249. is an example of what type of nuclear reaction?
250. is an example of what type of nuclear reaction?
251. is an example of what type of nuclear reaction?
252. is an example of what type of nuclear reaction?
253–260 Determine the missing part of the equation.
253.
254.
255.
256.
257.
258.
259.
260.
261–270 Answer the question on half-lives.
261. After five half-lives, how many grams of a 400 g radioactive sample remain undecayed?
262. After three half-lives, how many grams of a 50.0 g radioactive sample have decayed?
263. If 5.15 g of a radioactive sample remains undecayed after six half-lives, how many grams were in the original sample?
264. A radioactive sample starts with 1.500 × 1020 undecayed atoms. When measured again at a later date, the sample has 9.375 × 1018 undecayed atoms. How many half-lives have passed?
265. What fraction of a sample remains undecayed after 39 hours if the half-life of the sample is 13 hours?
266. Iodine-131 has a half-life of 8.02 days. If the original sample contained 25.0 g of iodine-131, how many grams have decayed after 56.14 days?
267. Strontium-90 has a half-life of 28.9 years. How many grams were in the original sample if 11 g remain undecayed after 115.6 years?
268. In 5 minutes, a radioactive sample decays from 2.56 × 1010 atoms to 8.00 × 108 atoms. How long is the isotope’s half-life?
269. What fraction of a sample has decayed after 320 days if the half-life of the sample is 160 days?
270. If a radioactive sample decays from 2.5 kg to 0.61 g and the isotope has a half-life of 9.35 hours, how much time has passed?
Chapter 5
The periodic table is much more than a simple listing of the symbols of the elements with additional information about each element. The position of an element on the periodic table indicates many of the element’s properties. In addition, the position gives information on how the properties of an element relate to those of its neighbors. However, watch out for exceptions to the general trends.
In this chapter, you work with periodicity and the periodic table in the following ways:
Note: For reference, you can find the periodic table in the Appendix.
Don’t let common mistakes trip you up; remember the following when working on periodicity and the periodic table:
271–290 Check your knowledge of the symbols and names of elements on the periodic table.
271. What is the symbol for the element carbon?
272. What is the symbol for the element chlorine?
273. What is the symbol for the element aluminum?
274. What is the symbol for the element cadmium?
275. What is the symbol for the element copper?
276. What is the symbol for the element arsenic?
277. What is the symbol for the element sodium?
278. What is the symbol for the element potassium?
279. What is the symbol for the element iron?
280. What is the symbol for the element silver?
281. What is the name of the element that has the symbol N?
282. What is the name of the element that has the symbol S?
283. What is the name of the element that has the symbol Br?
284. What is the name of the element that has the symbol P?
285. What is the name of the element that has the symbol Mn?
286. What is the name of the element that has the symbol At?
287. What is the name of the element that has the symbol Ra?
288. What is the name of the element that has the symbol Hg?
289. What is the name of the element that has the symbol Sn?
290. What is the name of the element that has the symbol Pa?
291–310 Answer the questions on the structure of the periodic table.
291. A period goes in which direction on the periodic table?
292. Where are the metalloids located in the periodic table?
293. Where on the periodic table are the alkaline earth metals located?
294. Where on the periodic table are the transition metals located?
295. Where on the periodic table are the noble gases located?
296. Where on the periodic table are the inner transition metals located?
297. Where on the periodic table are the alkali metals located?
298. Which chemist is most often recognized for basing the arrangement of the periodic table on atomic mass and other physical properties of the elements?
299. Which scientist placed the elements in order of increasing atomic number on the periodic table?
300. Where on the periodic table are most of the elements that exist as gases at room temperature?
301. To which family does the element potassium belong?
302. To which family does the element silver belong?
303. To which family does the element selenium belong?
304. To which family does the element tin belong?
305. To which family does the element iodine belong?
306. To which family does the element calcium belong?
307. To which family does the element aluminum belong?
308. To which family does the heaviest naturally occurring element belong?
309. Which family of elements contains the only metal that’s liquid at room temperature?
310. Which family of elements contains the only nonmetal that’s liquid at room temperature?
311–330 Examine your knowledge of periodic trends.
311. Members of which family have three valence electrons?
312. Members of which family have five valence electrons?
313. Members of which family have two valence electrons?
314. The atomic masses of the elements generally __________ (increase/decrease/remain the same) going from left to right in a period and __________ (increase/decrease/remain the same) going down a family.
315. The atomic radii of the elements __________ (increase/decrease/remain the same) going from left to right in a period and __________ (increase/decrease/remain the same) going down a family.
316. What term describes the amount of energy needed to remove an electron from a gaseous atom?
317. What term describes the energy change that results from adding an electron to a gaseous atom or ion?
318. The ionic radius of an anion is __________ (larger than/smaller than/the same size as) the atomic radius of the neutral atom because the ion has __________ (more/fewer/an equal number of) electrons compared to the atom.
319. The atomic radii of the elements __________ (increase/decrease/remain the same) going from left to right in a period because the effective nuclear charge __________ (increases/decreases).
320. Rank the following elements from smallest to largest atomic radius: Ba, Be, Ca.
321. Rank the following elements from smallest to largest atomic radius: Cl, P, S.
322. Rank the following elements from lowest to highest ionization energy: B, C, Li.
323. Rank the following elements from lowest to highest ionization energy: Br, Cl, I.
324. Rank the following elements from lowest to highest electron affinity: F, O, N.
325. Rank the following elements from lowest to highest electron affinity: S, Se, Te.
326. Rank the following elements from most to least metallic character: Cl, Si, Sn.
327. Rank the following elements from smallest to largest atomic radius: K, Mg, Na.
328. Rank the following ions from largest to smallest ionic radius: F–, O2–, S2–.
329. Rank the following elements from highest to lowest ionization energy: Cs, F, Li.
330. Rank the following elements from lowest to highest ionization energy: Ba, Bi, N.