Ch.2 - Atoms & ElementsSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Modern Atomic Theory states that matter is composed of small, indivisible particles called atoms. 

Three Laws of Modern Atomic Theory

Concept #1: The Conservation of Matter

The Law of Conservation of Mass states that matter can neither be created nor destroyed, all that happens is that it changes forms. 

Concept #2: Law of Definite Proportions

No matter where you obtain a compound, whether it’s from a lab experiment or from collection out in the field, the ratio of elements in it will remain constant. 

Concept #3: Law of Multiple Proportions

When element A and element B combine they can form different compounds in different ratios to one another. Dividing these different ratios should generate whole number answers. 

Example #1: A 15.39 g sample of iodine reacts with 62.92 g of chlorine to form iodine pentachloride, ICl5. If iodine pentachloride is the only product formed calculate its mass. 

Example #2: Two samples sodium fluoride decompose into their constituent elements. The first sample produces 15.8 kg of sodium and 20.1 kg of fluorine. If the second sample produces 192.0 g of sodium, how many grams of fluorine were also produced? 

Practice: Which of the following is an example of the law of multiple proportions?

Additional Problems
In a chemical reaction, matter is neither created or destroyed. Which law does this refer to? A) Law of Definite Proportions B) Law of the Conservation of Mass C) Law of Modern Atomic Theory D) Law of Multiple Proportions E) First Law of Thermodynamics
Drinking alcohol is also called ethyl alcohol or ethanol. Most of the ethanol produced in the USA comes from corn, an obviously natural source. It can also be made in the laboratory from natural gas (CH4) as a starting material. If you wanted to use ethanol from one of these sources, and price were not a consideration, decide which one you would choose. Which of the following laws listed below is most useful to you in making your decision?   a. The Law of Conservation of Mass b. The Law of Definite Proportions c. Dalton’s Atomic Theory d. The Law of Multiple Proportions e. Avogadro’s Hypothesis
Which procedure can be used to demostrate experimentally that this reaction obeys the Law of Conservation of Matter? 2 Mg (s) + O2 (g) → 2 MgO (s) (A) Take a mass of 1.0000 g of Mg ribbon, burn it in pure O2 , and compare the mass of the product with the original mass of the Mg. (B) Show that the sum of two atomic molar masses of Mg plus one molecular mass of O2 is equal to two formula molar masses of MgO. (C) Determine the mass of a sealed flash-bulb containing magnesium and oxygen, ignite the mixture, cool, and compare the final mass of bulb plus contents with the original mass of the bulb plus contents. (D) Burn 1.0000 g of Mg ribbon in a tall beaker filled with air, scrape out all the MgO formed and compare with the original mass of the Mg.
Which of the following sets illustrates the Law of Multiple Proportions?  
The statement, “In a chemical reaction, no matter is neither created nor destroyed.” Is called a. The Law of Conservation of Mass b. Dalton’s Atomic Theory c. The Scientific Methods d. The Law of Multiple Proportions e. The Law of Definite Proportions
Which of the following is NOT a component of Dalton’s Atomic Theory? A. A chemical reaction rearranges the grouping of atoms. B. Atoms are comprised of protons, neutrons, and electrons. C. Atoms of a given element are chemically and physically identical. D. Atoms of different elements combine in simple, whole number ratios to form compounds. E. Matter is composed of atoms, which cannot be created or destroyed.
A compound contains only calcium and fluorine. A sample of the compound is determined to contain 2.00 g of calcium and 1.90 g of fluorine. According to the Law of Definite Proportions, how much calcium should another sample of this compound contain if it contains 2.85 g of fluorine? a. 2.71 g b. 4.00 g c. 3.00 g d. 4.50 g e. 6.00 g
When a log burns, the mass of its products equals the mass of the log and oxygen. This is an example of which law? A. Law of Definite Proportions B. Law of Conservation of Mass C. Law of Multiple Proportions D. Law of Modern Atomic Theory E. First Law of Thermodynamics 
The two compounds, Fe3O4 and Fe2O3, illustrate the law of multiple proportions. For the same mass of iron in samples of each compound, what is the ratio of the masses of the oxygen in the compounds? A. 1 to 1 B. 2 to 3 C. 3 to 4 D. 7 to 8 E. 8 to 9
Which is the correct match of person and the law: when two elements form a series of compounds, the masses of the one element that combine with a fixed mass of the other element stand to one another in the ratio of small whole numbers. A. Democratus, atomic law B. Lavosier, law of conservation of mass C. Berthollet, law of definite proportions D. Dalton, law of multiple proportions E. Avagadro, law of moles
Which of the following statements is FALSE according to Dalton's Atomic Theory? A) An atom of nitrogen can be broken down into smaller particles that will still have the unique properties of nitrogen. B) Atoms combine in simple whole number ratios to form compounds. C) One carbon atom will combine with one oxygen atom to form a molecule of carbon monoxide. D) All atoms of chlorine have identical properties that distinguish them from other elements. E) Atoms of sodium do not change into another element during chemical reaction with chlorine.
The ratio of sulfur to oxygen by mass in SO2 is 1.0:1.0.Find the ratio of sulfur to oxygen by mass in SO3.
The ratio of sulfur to oxygen by mass in SO2 is 1.0:1.0.Find the ratio of sulfur to oxygen by mass in S2O.
The ratio of oxygen to carbon by mass in carbon monoxide is 1.33:1.00.Find the formula of an oxide of carbon in which the ratio by mass of oxygen to carbon is 2.00:1.00.
Ammonia ( NH3 ) and hydrazine ( N2 H4 ) are both binary compounds of nitrogen and hydrogen.Based on the law of multiple proportions, how many grams of hydrogen would you expect 2.36 g of nitrogen to combine with to yield ammonia?
The ratio of oxygen to nitrogen by mass in NO2 is 2.29. The ratio of fluorine to nitrogen by mass in NF3 is 4.07.Find the ratio of oxygen to fluorine by mass in OF2.
The ratio of the mass of O to the mass of N in N2O3 is 12:7. Another binary compound of nitrogen has a ratio of O to N of 16:7.What is its formula?
The ratio of the mass of O to the mass of N in N2O3 is 12:7. Another binary compound of nitrogen has a ratio of O to N of 16:7.What is the ratio of O to N in the next member of this series of compounds?
A compound containing only carbon and hydrogen has a carbon-to-hydrogen mass ratio of 11.89. You may want to reference (Page 50) Section 2.3 while completing this problem.Which carbon-to-hydrogen mass ratio is possible for another compound composed only of carbon and hydrogen?
Benzene, ethane, and ethylene are just three of a large number of hydrocarbons-compounds that contain only carbon and hydrogen. Show how the following data are consistent with the law of multiple proportions. Compound Mass of carbon in 5.00 g sample Mass of hydrogen in 5.00 g sample Benzene 4.61 g 0.39 g Ethane 4.00 g 1.00 g Ethylene 4.29 g 0.71 g
Palladium forms three different compounds with sulfur. The mass of sulfur per gram of palladium in each compound is listed below: Compound Grams S per Gram Pd A 0.603 B 0.301 C 0.151 Are these masses consistent with the law of multiple proportions?
Palladium forms three different compounds with sulfur. The mass of sulfur per gram of palladium in each compound is listed below: Compound Grams S per Gram Pd A 0.603 B 0.301 C 0.151 Why are the masses consistent with the law of multiple proportions?
Sulfur and oxygen form both sulfur dioxide and sulfur trioxide. When samples of these are decomposed, the sulfur dioxide produces 3.50 g oxygen and 3.51 g sulfur, while the sulfur trioxide produces 8.25 g oxygen and 5.50 g sulfur.Calculate the mass of oxygen per gram of sulfur for sulfur dioxide.
Sulfur and oxygen form both sulfur dioxide and sulfur trioxide. When samples of these are decomposed, the sulfur dioxide produces 3.50 g oxygen and 3.51 g sulfur, while the sulfur trioxide produces 8.25 g oxygen and 5.50 g sulfur.Calculate the mass of oxygen per gram of sulfur for sulfur trioxide.
Sulfur and oxygen form both sulfur dioxide and sulfur trioxide. When samples of these are decomposed, the sulfur dioxide produces 3.50 g oxygen and 3.51 g sulfur, while the sulfur trioxide produces 8.25 g oxygen and 5.50 g sulfur.Are the results consistent with the law of multiple proportions?
State the law of multiple proportions.
Two different compounds containing osmium and oxygen have the following masses of oxygen per gram of osmium: 0.168 and 0.3369 g.Show that these amounts are consistent with the law of multiple proportions.
Sulfur and fluorine form several different compounds including sulfur hexafluoride and sulfur tetrafluoride. Decomposition of a sample of sulfur hexafluoride produced 4.46 g of fluorine and 1.25 g of sulfur, while decomposition of a sample of sulfur tetrafluoride produced 4.44 g of fluorine and 1.87 g of sulfur.Calculate the mass of fluorine per gram of sulfur for the sample of sulfur hexafluoride.
Sulfur and fluorine form several different compounds including sulfur hexafluoride and sulfur tetrafluoride. Decomposition of a sample of sulfur hexafluoride produced 4.46 g of fluorine and 1.25 g of sulfur, while decomposition of a sample of sulfur tetrafluoride produced 4.44 g of fluorine and 1.87 g of sulfur.Show that these results are consistent with the law of multiple proportions.
You may want to reference (Pages 48 - 51) Section 2.3 while completing this problem. Hydrogen and oxygen form both water and hydrogen peroxide. A decomposition of a sample of water forms 0.125 g hydrogen to every 1.00 g oxygen. The decomposition of a sample of hydrogen peroxide forms 0.0625 g hydrogen to every 1.00 g oxygen. Show that these results are consistent with the law of multiple proportions.
When carbon and oxygen react, two different compounds can form depending on the conditions.Compound A contains 1.836 g of oxygen per gram of carbon, whereas compound B contains 3.672 g of oxygen per gram of carbon. What chemical law do these data illustrate?
When carbon and oxygen react, two different compounds can form depending on the conditions.If compound A has an equal number of oxygen and carbon atoms, what can we conclude about the composition of compound B?
Ammonia (NH3) and hydrazine (N2H4) are both compounds of nitrogen and hydrogen.Based on the law of multiple proportions, how many grams of hydrogen would you expect 2.76 g of nitrogen to combine with to yield ammonia?
Compounds A and B are colorless gases obtained by combining sulfur with oxygen. Compound A results from combining 6.00g of sulfur with 5.99 g of oxygen, and compound B results from combining 8.60g of sulfur with 12.88 g of oxygen.If the chemical formula of compound A in this problem is SO2, what is the chemical formula of compound B?
Compounds A and B are colorless gases obtained by combining sulfur with oxygen. Compound A results from combining 6.00g of sulfur with 5.99 g of oxygen, and compound B results from combining 8.60g of sulfur with 12.88 g of oxygen.Show that the mass ratios in the two compounds are simple multiples of each other.
You may want to reference (Pages 43 - 45) Section 2.5 while completing this problem.Two compounds containing carbon and oxygen have the following percent composition by mass: Compound 1 is 42.9 % carbon and 57.1 % oxygen. Compound 2 is 27.3 % carbon and 72.7 % oxygen. Show that the law of multiple proportions is followed.
In a series of experiments, a chemist prepared three different compounds that contain only iodine and fluorine and determined the mass of each element in each compound: Compound Mass of iodine (g) Mass of fluorine (g) 1 4.75 3.56 2 7.64 3.43 3 9.41 9.86 You may want to reference (Pages 44 - 45)Section 2.1 while completing this problem.Calculate the mass of fluorine per gram of iodine in Compound 2.
In a series of experiments, a chemist prepared three different compounds that contain only iodine and fluorine and determined the mass of each element in each compound: Compound Mass of iodine (g) Mass of fluorine (g) 1 4.75 3.56 2 7.64 3.43 3 9.41 9.86 You may want to reference (Pages 44 - 45)Section 2.1 while completing this problem.Calculate the mass of fluorine per gram of iodine in the third compound.
A 2.3-g sample of carbon dioxide (CO2) is fully decomposed into its elements, yielding 0.628 g of carbon and 1.67 g of oxygen. You may want to reference (Pages 44 - 45) Section 2.1 while completing this problem.If a sample of a different compound decomposes into 0.429 g of carbon and 0.571 g of oxygen, what is its ratio of the mass of O to C?
The atomic weight of carbon (12.011) is approximately 12 times that of hydrogen (1.008). Use this knowledge and the following data to calculate possible formulas for benzene, ethane, and ethylene. Compound Mass of carbon in 5.00 g sample Mass of hydrogen in 5.00 g sample Benzene 4.61 g 0.39 g Ethane 4.00 g 1.00 g Ethylene 4.29 g 0.71 g
Compounds A and B are colorless gases obtained by combining sulfur with oxygen. Compound A results from combining 6.00 g of sulfur with 5.99 g of oxygen, and compound B results from combining 8.60 g of sulfur with 12.88 g of oxygen. Show that the mass ratios in the two compounds are simple multiples of each other.
A 7.74 g sample of HCN is found to contain 0.287 g of H and 4.01 g of N.Find the mass of carbon in a sample of HCN with a mass of 3.43 g .
If 5.688 g of nitrogen combines with 0.8185 g of hydrogen to yield compound X, how many grams of nitrogen would combine with 1.520 g of hydrogen to make the same compound?
In addition to carbon monoxide CO and carbon dioxide CO2, there is a third compound of carbon and oxygen called carbon suboxide. If a 2.500 g sample of carbon suboxide contains 1.32 g of C and 1.18 g of O, what is a possible formula for carbon suboxide?
The chloride of an unknown metal is believed to have the formula MCl3. A 1.891 g sample of the compound is found to contain 3.606 10 - 2 mol Cl.Find the atomic mass of M.
How many atoms of Mg, O, and H are represented by the notation 3 formula units Mg(OH)2?
Two samples of carbon tetrachloride were decomposed into their constituent elements. One sample produced 38.9 g of carbon and 451 g of chlorine, and the other sample produced 14.8 g of carbon and 141 g of chlorine.Are these results consistent with the law of definite proportions?
Two samples of sodium chloride were decomposed into their constituent elements. One sample produced 6.51 g of sodium and 10.0 g of chlorine, and the other sample produced 13.1 g of sodium and 20.2 g of chlorine.Are these results consistent with the law of definite proportions?
The mass ratio of sodium to fluorine in sodium fluoride is 1.21:1. A sample of sodium fluoride produced 25.7 g of sodium upon decomposition.How much fluorine (in grams) was formed?
The molecular formula for water is H2O. Which ratio can be correctly derived from this formula?
Two samples of a compound containing elements A and B are decomposed. The first sample produces 15 g of A and 35 g of B. You may want to reference (Page 49) Section 2.3 while completing this problem.The second sample produces 10 g of A and what mass of B?
Explain the difference between the law of definite proportions and the law of multiple proportions.
How many hydrogen atoms are in each of the following:Ca(C2H5COO)2
Determine the number of each type of atom in each formula:Ca3 (PO4 )2
State the law of definite proportions.
Determine the number of each type of atom in each formula:SrCl2
Determine the number of each type of atom in each formula:KNO3
Determine the number of each type of atom in each formula:Mg(NO2 )2
Upon decomposition, one sample of magnesium fluoride produces 1.66 kg of magnesium and 2.58 kg of fluorine. A second sample produces 1.32 kg of magnesium. You may want to reference (Pages 48 - 51) Section 2.3 while completing this problem.How much fluorine (in grams) does the second sample produce?
You may want to reference (Pages 48 - 51) Section 2.3 while completing this problem.Two samples of carbon monoxide are decomposed into their constituent elements. One sample produces 17.2 g of oxygen and 12.9 g of carbon, and the other sample produces 10.5 g of oxygen and 7.88 g of carbon. Which pair of ratios accurately demonstrates that the results are consistent with the law of definite proportions?
You may want to reference (Pages 91 - 92) Section 3.3 while completing this problem. Determine the number of each type of atom in each formula:Ba(OH)2
You may want to reference (Pages 91 - 92) Section 3.3 while completing this problem. Determine the number of each type of atom in each formula:NH4 Cl
You may want to reference (Pages 91 - 92) Section 3.3 while completing this problem. Determine the number of each type of atom in each formula:NaCN
You may want to reference (Pages 91 - 92) Section 3.3 while completing this problem. Determine the number of each type of atom in each formula:Ba(HCO3 )2
Consider CH4.Does the formula contain more than one type of atom?
Compounds A and B are colorless gases obtained by combining sulfur with oxygen. Compound A results from combining 6.00g of sulfur with 5.99 g of oxygen, and compound B results from combining 8.60g of sulfur with 12.88 g of oxygen.Calculate the O/S mass ratio in the compound A.
Compounds A and B are colorless gases obtained by combining sulfur with oxygen. Compound A results from combining 6.00g of sulfur with 5.99 g of oxygen, and compound B results from combining 8.60g of sulfur with 12.88 g of oxygen.Calculate the O/S mass ratio in the compound B.
Write a ratio showing the relationship between the amounts of each element for each of the following: (a)
Write a ratio showing the relationship between the amounts of each element for each of the following: (b)
Write a ratio showing the relationship between the amounts of each element for each of the following: (c)
Write a ratio showing the relationship between the amounts of each element for each of the following:(a)
Write a ratio showing the relationship between the amounts of each element for each of the following:(b)
In methane, one part hydrogen combines with three parts carbon by mass.If a sample of a compound containing only carbon and hydrogen contains 32.0 g of carbon and 8.0 g of hydrogen, could the sample be methane?
Write a ratio showing the relationship between the amounts of each element for each of the following:(c)
A sample of ascorbic acid (vitamin C) is synthesized in the laboratory. It contains 1.50 g of carbon and 2.00 g of oxygen. Another sample of ascorbic acid isolated from citrus fruits contains 6.40 g of carbon.According to the law of constant composition, how many grams of oxygen does it contain?
In borane, one part hydrogen combines with 3.6 parts boron by mass. A compound containing only hydrogen and boron contains 6.0 g of hydrogen and 43.2 g of boron.Could this compound be borane?
A 2.3-g sample of carbon dioxide (CO2) is fully decomposed into its elements, yielding 0.628 g of carbon and 1.67 g of oxygen. You may want to reference (Pages 44 - 45) Section 2.1 while completing this problem.What is the ratio of the mass of O to C?
Hydrogen sulfide is composed of two elements: hydrogen and sulfur. In an experiment, 6.700 g of hydrogen sulfide is fully decomposed into its elements.What fundamental law does this experiment demonstrate?
When a small log completely burns in a campfire, the mass of the ash is much less than the mass of the log.What happens to the matter that composed the log?
1.00 g of C4H10 reacts with 3.59 g of O2 to form 3.03 g of CO2.Using only addition and subtraction, calculate the amount of H2O produced.
State the law of conservation of mass.
An automobile gasoline tank holds 23 kg of gasoline. When the gasoline burns, 84 kg of oxygen is consumed, and carbon dioxide and water are produced. You may want to reference (Pages 48 - 51) section 2.3 while completing this problem.What is the total combined mass of carbon dioxide and water that is produced?
A hydrogen-filled balloon was ignited and 1.90 g of hydrogen reacted with 15.2 g of oxygen.How many grams of water vapor were formed? (Assume that water vapor is the only product.)
Assume that the mixture of substances in drawing undergoes a reaction.Which of the drawings (b)-(d) represent a product mixture consistent with the law of mass conservation?
How does Daltons atomic theory account for the law of mass conservation?
How does Daltons atomic theory account for the law of definite proportions?
What is the law of multiple proportions, and how does Daltons atomic theory account for it?
How was Dalton able to convince others to accept an idea that had been controversial for 2000 years?
Summarize the history of the atomic idea.
What are the main ideas in Daltons atomic theory?
Explain the plum-pudding model of the atom.
Which of the following statements are inconsistent with Daltons atomic theory as it was originally stated?All carbon atoms are identical.
Which of the following statements are inconsistent with Daltons atomic theory as it was originally stated?An oxygen atom combines with 1.5 hydrogen atoms to form a water molecule.
Which of the following statements are inconsistent with Daltons atomic theory as it was originally stated?Two oxygen atoms combine with a carbon atom to form a carbon dioxide molecule.
Which of the following statements are inconsistent with Daltons atomic theory as it was originally stated?The formation of a compound often involves the destruction of one or more atoms.
What is Brownian motion? How is it related to the development of the idea that matter is particulate?
A chemist finds that 30.82 g of nitrogen will react with 17.60 g, 35.20 g, 70.40 g, or 88.00 g of oxygen to form four different compounds.Calculate the mass of oxygen per gram of nitrogen in each compound.30.82 g N2 and 17.60 g O2
The results from Thomsons cathode-ray tube experiment led to the discovery of which subatomic particle(s)?
What affects the magnitude of the deflection of the cathode ray in Thomsons experiment?
What property was measured in Thomsons cathode-ray experiment?
A 2.3-g sample of carbon dioxide (CO2) is fully decomposed into its elements, yielding 0.628 g of carbon and 1.67 g of oxygen. You may want to reference (Pages 44 - 45) Section 2.1 while completing this problem.According to Dalton’s atomic theory, what is the empirical formula of the second compound?
Which statements are inconsistent with Dalton's atomic theory as it was originally stated? Why?A. All carbon atoms are identical.B. An oxygen atom combines with 1.5 hydrogen atoms to form a water molecule.C. Two oxygen atoms combine with a carbon atom to form a carbon dioxide molecule.D. The formation of a compound often involves the destruction of one or more atoms.
Which quantity or quantities must always be the same on both sides of a chemical equation?I. the number of atoms of each kindII. the number of molecules of each kindIII. The mass of the reactants is equal to the mass of the products.A. I onlyB. II onlyC. III onlyD. Both I and IIIE. All of the above
A volatile liquid (one that easily evaporates) is put into a jar and the jar is then sealed. Does the mass of the sealed jar and its contents change upon the vaporization of the liquid? 
A 12.39 g sample of phosphorus reacts with 42.54 g of chlorine to form only phosphorus trichloride (PCl3). If it is the only product, what mass of PCl 3 is formed?A) 140.01 gB) 30.15 gC) 91.86 gD) 79.71 gE) 54.93 g
Which quantity or quantities must always be the same on both sides of a chemical equation? Check all that apply.a. the number of molecules of each kindb. the sum of the masses of all substances involvedc. the number of moles of each kind of moleculed. the number of atoms of each kind
Two samples of potassium iodide are decomposed into their constituent elements. The first sample produced 13.0 g of potassium and 42.3 g of iodine. If the second sample produced 24.4 kg of potassium, how many kg of iodine were produced?A) 13.3 kgB) 22.5 kgC) 79.4 kgD) 44.4 kgE) 92.4 kg
Determine the number of each type of atom in each formula: a. Ca(NO2)2
Determine the number of each type of atom in each formula: b. CuSO4
You have two beakers, one filled to the 100-mL mark with sugar (the sugar has a mass of 180.0 g) and the other filled to the 100-mL mark with water (the water has a mass of 100.0 g). You pour all the sugar and all the water together in a bigger beaker and stir until the sugar is completely dissolved. a. Which of the following is true about the mass of the solution? Explain.i. It is much greater than 280.0 g.ii. It is somewhat greater than 280.0 g.iii. It is exactly 280.0 g.iv. It is somewhat less than 280.0 g.v. It is much less than 280.0 g.
You have two beakers, one filled to the 100-mL mark with sugar (the sugar has a mass of 180.0 g) and the other filled to the 100-mL mark with water (the water has a mass of 100.0 g). You pour all the sugar and all the water together in a bigger beaker and stir until the sugar is completely dissolved. b. Which of the following is true about the volume of the solution? Explain.i. It is much greater than 200.0 mL.ii. It is somewhat greater than 200.0 mL.iii. It is exactly 200.0 mL.iv. It is somewhat less than 200.0 mL.v. It is much less than 200.0 mL.
Determine the number of each type of atom in each formula: c. Al(NO3)3
A 7.83-g sample of HCN is found to contain 0.290 g of H and 4.06 g of N. Find the mass of carbon in a sample of HCN with a mass of 3.37 g.
Determine the number of each type of atom in each formula: d. Mg(HCO3)2
The ratio of sulfur to oxygen by mass in SO 2 is 1.0:1.0.a. Find the ratio of sulfur to oxygen by mass in SO 3.b. Find the ratio of sulfur to oxygen by mass in S 2O.
What theory did John Dalton formulate? 
The ratio of oxygen to carbon by mass in carbon monoxide is 1.33:1.00. Find the formula of an oxide of carbon in which the ratio by mass of oxygen to carbon is 2.00:1.00.
Which of the following is an example of the law of multiple proportions?A) A sample of chlorine is found to contain three times as much Cl-35 as Cl-37.B) Two different compounds formed from carbon and oxygen have the following mass ratios: 1.33 g O: 1 g C and 2.66 g O: 1 g C.C) Two different samples of table salt are found to have the same ratio of sodium to chlorine.D) The atomic mass of bromine is found to be 79.90 amu.E) Nitrogen dioxide always has a mass ratio of 2.28 g O: 1 g N.
What observations did Lavoisier make? What law did he formulate? 
The ratio of the mass of a nitrogen atom to the mass of an atom of   12C is 7:6 and the ratio of the mass of nitrogen to oxygen in N2O is 7:4. Find the mass of 1 mol of oxygen atoms.
 A hydrogen-filled balloon was ignited and 1.50 g of hydrogen reacted with 12.0 g of oxygen. How many grams of water vapor were formed? (Assume that water vapor is the only product.) 
An automobile gasoline tank holds 21 kg of gasoline. When the gasoline burns, 84 kg of oxygen is consumed, and carbon dioxide and water are produced. What is the total combined mass of carbon dioxide and water that is produced? 
How many of the indicated atoms are represented by each chemical formula: (a) carbon atoms in C2H5COOCH3
How many of the indicated atoms are represented by each chemical formula: (b) oxygen atoms in Ca(ClO4)2
How many of the indicated atoms are represented by each chemical formula: (c) hydrogen atoms in (NH4)2HPO4?
The smallest unit of an element that has all of the properties of the element is a/an a. molecule. b. cell. c. atom. d. neutron.
Two samples of carbon tetrachloride were decomposed into their constituent elements. One sample produced 38.9 g of carbon and 448 g of chlorine, and the other sample produced 14.8 g of carbon and 134 g of chlorine. Are these results consistent with the law of definite proportions? Show why or why not. 
A sample of ascorbic acid (vitamin C) is synthesized in the laboratory. It contains 1.50 g of carbon and 2.00 g of oxygen. Another sample of ascorbic acid isolated from citrus fruits contains 6.35 g of carbon. How many grams of oxygen does it contain? Which law are you assuming in answering this question?
The mass ratio of sodium to fluorine in sodium fluoride is 1.21: 1. A sample of sodium fluoride produced 28.8 g of sodium upon decomposition. How much fluorine (in grams) was formed?
Upon decomposition, one sample of magnesium fluoride produced 1.65 kg of magnesium and 2.57 kg of fluorine. A second sample produced 1.32 kg of magnesium. How much fluorine (in grams) did the second sample produce?
Palladium forms three different compounds with sulfur. The mass of sulfur per gram of palladium in each compound is listed below: Show that these masses are consistent with the law of multiple proportions. 
Dalton used the lightest element as his standard for atomic mass. What is this element? a. Oxygen b. Carbon c. Hydrogen d. Nitrogen
What is the ratio of oxygen atoms to hydrogen atoms in the mineral aluminite Al2(SO4)(OH)4 . 7H2O?a. 8:4b. 15:18c. 18:15d. 15:11e. 11:15
What is the modern view of the structure of the atom?
The ratio of oxygen to nitrogen by mass in NO 2 is 2.29. The ratio of fluorine to nitrogen by mass in NF3 is 4.07. Find the ratio of oxygen to fluorine by mass in OF 2.  
A substance composed of 2 or more elements in a fixed, definite proportion is consideredA) a homogeneous mixture.B) a heterogeneous mixture.C) a compound.D) a solution.E) an alloy.
Which of the following is an example of the law of multiple proportions? Explaina. Two different samples of water are found to have the same ratio of hydrogen to oxygenb. When hydrogen and oxygen react to form water, the mass of water formed is exactly equal to the mass of hydrogen and oxygen that reacted. c. The mass ratio of oxygen to hydrogen in water is 8:1. The mass ratio of oxygen to hydrogen in hydrogen peroxide. (a compound that only contains hydrogen and oxygen) is 16: 1. 
A sample of H2SO4 contains 2.02 g of hydrogen, 32.07 g of sulfur, and 64.00 g of oxygen. How many grams of sulfur and grams of oxygen are present in a second sample of H2SO4 containing 7.27 g of hydrogen?
Two elements, R and Q, combine to form two binary compounds. In the first compound, 14.0 g of R combines with 3.00 g of Q. In the second compound, 7.00 g of R combines with 4.50 g of Q. Show that these data are in accord with the law of multiple proportions. If the formula of the second compound is RQ, what is the formula of the first compound?
Which of the following chemical reactions is/are NOT possible according to Dalton's atomic theory?a. reaction 1: CCl4 → CH4b. reaction 2: N2 + 3H2 → 2NH3c. reaction 3: 2H2 + O2 → 2H2O + Au
In a reaction, 34.0 g of chromium(III) oxide reacts with 12.1 g of aluminum to produce chromium and aluminum oxide. If 23.3 gof chromium is produced, what mass of aluminum oxide is produced?
Use the box color(s) in the periodic table below to identify the element(s) described by each of the following:(l) A pair of elements whose compounds exhibit the law of multiple proportions
When the mixture of gaseous H2 and gaseous  Cl2 react, a product forms that has the same properties regardless of the relative amounts of H2 and gaseous  Cl2 used.b.  When a volume of H2 reacts with an equal volume of Cl2 at the same temperature and pressure, what volume of product having the formula HCl is formed?
Sulfur and fluorine form several different compounds including sulfur hexafluoride and sulfur tetrafluoride. Decomposition of a sample of sulfur hexafluoride produced 4.46 g of fluorine and 1.25 g of sulfur, while decomposition of a sample of sulfur tetrafluoride produced 4.44 g of fluorine and 1.87 g of sulfur.Calculate the mass of fluorine per gram of sulfur for the sample of sulfur tetrafluoride.
Observations of the reaction between nitrogen gas and hydrogen gas show us that 1 volume of nitrogen reacts with 3 volumes of hydrogen to make 2 volumes of gaseous product, as shown below:Determine the formula of the product and justify your answer.
Hydrazine, ammonia, and hydrogen azide all contain only nitrogen and hydrogen. The mass of hydrogen that combines with 1.00 g of nitrogen for each compound is 1.44x 10-1 g, 2.16 x 10-1 g, and 2.40 x 10-2 g, respectively. Show how these data illustrate the law of multiple proportions.
Consider 100.0-g samples of two different compounds consisting only of carbon and oxygen. One compound contains 27.2 g of carbon and the other has 42.9 g of carbon. How can these data support the law of multiple proportions if 42.9 is not a multiple of 27.2? Show that these data support the law of multiple proportions.
The three most stable oxides of carbon are carbon monoxide (CO), carbon dioxide (CO2), and carbon suboxide (C3O2). The molecules can be represented asExplain how these molecules illustrate the law of multiple proportions.
Two elements, R and Q, combine to form two binary compounds. In the first compound, 14.0 g of R combines with 3.00 g of Q. In the second compound, 7.00 g of R combines with 4.50 g of Q. Show that these data are in accord with the law of multiple proportions. If the formula of the second compound is RQ, what is the formula of the first compound?
Show, with calculations, how the following data illustrate the law of multiple proportions:Compound 1: 47.5 mass % sulfur and 52.5 mass % chlorineCompound 2: 31.1 mass % sulfur and 68.9 mass % chlorine
Show, with calculations, how the following data illustrate the law of multiple proportions:Compound 1: 77.6 mass % xenon and 22.4 mass % fluorineCompound 2: 63.3 mass % xenon and 36.7 mass % fluorine
Scenes A–I on the next page depict various types of matter on the atomic scale. Choose the correct scene(s) for each of the following:(a) A mixture that fills its container(b) A substance that cannot be broken down into simpler ones(c) An element with a very high resistance to flow(d) A homogeneous mixture(e) An element that conforms to the walls of its container and displays an upper surface(f) A gas consisting of diatomic particles(g) A gas that can be broken down into simpler substances(h) A substance with a 2/1 ratio of its component atoms(i) Matter that can be separated into its component substances by physical means(j) A heterogeneous mixture(k) Matter that obeys the law of definite composition
Can the relative amounts of the components of a compound vary? Explain.
How many molecules of C2H4Cl2 can be prepared from 15 C2H4 molecules and 8 Cl2 molecules?
How many molecules of the sweetener saccharin can be prepared from 30 C atoms, 25 H atoms, 12 O atoms, 8 S atoms, and 14 N atoms?
Dinitrogen monoxide (N2O; nitrous oxide) is a greenhouse gas that enters the atmosphere principally from natural fertilizer breakdown. Some studies have shown that the isotope ratios of 15N to 14N and of 18O to 16O in N2O depend on the source, which can thus be determined by measuring the relative abundances of molecular masses in a sample of N2O. (a) What different molecular masses are possible for N2O?
Dinitrogen monoxide (N2O; nitrous oxide) is a greenhouse gas that enters the atmosphere principally from natural fertilizer breakdown. Some studies have shown that the isotope ratios of 15N to 14N and of 18O to 16O in N2O depend on the source, which can thus be determined by measuring the relative abundances of molecular masses in a sample of N2O. (b) The percent abundance of 14N is 99.6%, and that of 16O is 99.8%. Which molecular mass of N2O is least common, and which is most common?
The two isotopes of potassium with significant abundances in nature are  39K (isotopic mass = 38.9637 amu, 93.258%) and 41K (isotopic mass = 40.9618 amu, 6.730%). Fluorine has only one naturally occurring isotope, 19F (isotopic mass = 18.9984 amu). Calculate the formula mass of potassium fluoride.
A sample of chloroform is found to contain 12.0 g of carbon, 106.4 g of chlorine, and 1.01 g of hydrogen. If a second sample of chloroform is found to contain 30.0 g of carbon, what is the total mass of chloroform in the second sample?
A sample of H2SO4 contains 2.02 g of hydrogen, 32.07 g of sulfur, and 64.00 g of oxygen. How many grams of sulfur and grams of oxygen are present in a second sample of H2SO4 containing 7.27 g of hydrogen?
Give the number of atoms of the specified element in a formula unit of each of the following compounds, and calculate the molecular (formula) mass:(a) Oxygen in aluminum sulfate, Al2(SO4)3
Give the number of atoms of the specified element in a formula unit of each of the following compounds, and calculate the molecular (formula) mass:(b) Hydrogen in ammonium hydrogen phosphate, (NH4)2HPO4
Give the number of atoms of the specified element in a formula unit of each of the following compounds, and calculate the molecular (formula) mass:(c) Oxygen in the mineral azurite, Cu 3(OH)2(CO3)2
Give the number of atoms of the specified element in a formula unit of each of the following compounds, and calculate the molecular (formula) mass:(a) Hydrogen in ammonium benzoate, C6H5COONH4
A compound of copper and sulfur contains 88.39 g of metal and 44.61 g of nonmetal. How many grams of copper are in 5264 kg of compound? How many grams of sulfur?
Give the number of atoms of the specified element in a formula unit of each of the following compounds, and calculate the molecular (formula) mass:(b) Nitrogen in hydrazinium sulfate, N2H6SO4
A compound of iodine and cesium contains 63.94 g of metal and 61.06 g of nonmetal. How many grams of cesium are in 38.77 g of compound? How many grams of iodine?
Give the number of atoms of the specified element in a formula unit of each of the following compounds, and calculate the molecular (formula) mass:(c) Oxygen in the mineral leadhillite, Pb 4SO4(CO3)2(OH)2
You are working in the laboratory preparing sodium chloride. Consider the following results for three preparations of the compound:Case 1:     39.34 g Na + 60.66 g Cl 2 ⟶ 100.00 g NaClCase 2:    39.34 g Na + 70.00 g Cl 2 ⟶ 100.00 g NaCl + 9.34 g Cl 2Case 3:    50.00 g Na + 50.00 g Cl 2 ⟶ 82.43 g NaCl + 17.57 g NaExplain these results in terms of the laws of conservation of mass and definite composition.
The following scenes represent a mixture of two monatomic gases undergoing a reaction when heated. Which mass law(s) is (are) illustrated by this change?
The early alchemists used to do an experiment in which water was boiled for several days in a sealed glass container. Eventually, some solid residue would appear in the bottom of the flask, which was interpreted to mean that some of the water in the flask had been converted into “earth.” When Lavoisier repeated this experiment, he found that the water weighed the same before and after heating and the mass of the flask plus the solid residue equaled the original mass of the flask. Were the alchemists correct? Explain what happened. (This experiment is described in the article by A. F. Scott in Scientific American, January 1984.)
In a reaction, 34.0 g of chromium(III) oxide reacts with 12.1 g of aluminum to produce chromium and aluminum oxide. If23.3 g of chromium is produced, what mass of aluminum oxide is produced?
Which of the postulates of Dalton's atomic theory explains why we can calculate a theoretical yield for a chemical reaction?
When elemental iron corrodes it combines with oxygen in the air to ultimately form red brown iron(III) oxide which we call rust. (a) If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you expect the mass to have increased, decreased, or remained the same? Explain.(b) If the mass of the iron nail increases to 24.1 g, what mass of oxygen combined with the iron?
As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place:(a) Exactly one pound of bread dough is placed in a baking tin. The dough is cooked in an oven at 350 °F releasing a wonderful aroma of freshly baked bread during the cooking process. Is the mass of the baked loaf less than, greater than, or the same as the one pound of original dough? Explain.
As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place:(b) When magnesium burns in air a white flaky ash of magnesium oxide is produced. Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium? Explain.
Yeast converts glucose to ethanol and carbon dioxide during anaerobic fermentation as depicted in the simple chemical equation here: glucose ⟶ ethanol + carbon dioxide(a) If 200.0 g of glucose is fully converted, what will be the total mass of ethanol and carbon dioxide produced?
Yeast converts glucose to ethanol and carbon dioxide during anaerobic fermentation as depicted in the simple chemical equation here: glucose ⟶ ethanol + carbon dioxide(b) If the fermentation is carried out in an open container, would you expect the mass of the container and contents after fermentation to be less than, greater than, or the same as the mass of the container and contents before fermentation? Explain.
In Section 1‑1 of the text, the concept of a chemical reaction was introduced with the example of the decomposition of water, represented as follows:Use ideas from Dalton’s atomic theory to explain how the above representation illustrates the law of conservation of mass.
In a combustion reaction, 46.0 g of ethanol reacts with 96.0 g of oxygen to produce water and carbon dioxide. If 54.0 g of water is produced, what mass of carbon dioxide is produced?
State the mass law(s) demonstrated by the following experimental results, and explain your reasoning:Experiment 1: A student heats 1.27 g of copper and 3.50 g of iodine to produce 3.81 g of a white compound; 0.96 g of iodine remains.Experiment 2: A second student heats 2.55 g of copper and 3.50 g of iodine to form 5.25 g of a white compound; 0.80 g of copper remains.
Identify the postulate of Dalton’s theory that is violated by the following observations: 59.95% of one sample of titanium dioxide is titanium; 60.10% of a different sample of titanium dioxide is titanium.
Describe Thomson’s model of the atom. How might it account for the production of cathode rays?
Which of the following is(are) correct?a. 40Ca2+ contains 20 protons and 18 electrons.b. Rutherford created the cathode-ray tube and was thefounder of the charge-to-mass ratio of an electron.c. An electron is heavier than a proton.d. The nucleus contains protons, neutrons, and electrons.
As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place:(c) Antoine Lavoisier, the French scientist credited with first stating the law of conservation of matter, heated a mixture of tin and air in a sealed flask to produce tin oxide. Did the mass of the sealed flask and contents decrease, increase, or remain the same after the heating?
In the following drawing, the green spheres represent atoms of a certain element. The purple spheres represent atoms of another element. If the spheres of different elements touch, they are part of a single unit of a compound. The following chemical change represented by these spheres may violate one of the ideas of Dalton’s atomic theory. Which one?
Which postulate of Dalton’s theory is consistent with the following observation concerning the weights of reactants and products? When 100 grams of solid calcium carbonate is heated, 44 grams of carbon dioxide and 56 grams of calcium oxide are produced.
Which of Dalton’s postulates about atoms are inconsistent with later observations? Do these inconsistencies mean that Dalton was wrong? Is Dalton’s model still useful? Explain.
Use Dalton’s theory to explain why potassium nitrate from India or Italy has the same mass percents of K, N, and O.
If you wanted to make an accurate scale model of the hydrogen atom and decided that the nucleus would have a diameter of 1 mm, what would be the diameter of the entire model?
Identify the postulate of Dalton’s theory that is violated by the following observations: 59.95% of one sample of titanium dioxide is titanium; 60.10% of a different sample of titanium dioxide is titanium.
How many moles of N are in 0.237 g of N20?
Exactly 1 mol of Ba(NO3)2 contains how many moles of Ba, N, and O? 
A hydrocarbon is a compound that contains mostly carbon and hydrocarbon, Calculate the percent composition (by mass) of the following hydrocarbon: C6H14. Enter the percentages of carbon and hydrogen numerically to four significant figures, separated by commas. 
How many moles of N are in 0.237 g of N2O?
How many O atoms are there in 7.527 x 1023 molecules of trifluoroacetic acid, C2HF3O2?
Exactly 1 mol of AlPO4 contains how many moles of Al, P. and O? Al = P = O =
The fuel used in many disposable lighters is liquid butane, C4H10. How many carbon atoms are in 2.00 g of butane given that the molar mass of butane is 58.12 g/mol? Express your answer numerically in atoms.
A sample of C3H8 has 4.00 x 1024 H atoms. How many carbon atoms does the sample contain? What is the total mass of the sample?
Use the law of constant composition to complete the following table summarizing the amounts of nitrogen and oxygen produced upon the sample of dinitrogen monoxide. Enter your answers numerically separated by a comma. 
This is the chemical formula for methyl tert-butyl ether (the clean-fuel gasoline additive MTBE): CH3OC(CH3)3 A chemical engineer has determined by measurements that there are 0.0184 moles of carbon in a sample of methyl tert-butyl ether. How many moles of oxygen are in the sample? Round your answer to 3 significant digits.
Answer the following questions using the law of conservation of mass.Consider a hypothetical reaction in which A and B are reactants and C and D are products. If 23 grams of A completely reacts with 29 grams of B to produce 18 grams of C, how many grams of D will be produced? A 3.4 gram sample of sodium hydrogen carbonate is added to a solution of acetic acid weighing 10.1 grams. The two substances react, releasing carbon dioxide gas to the atmosphere. After the reaction, the contents of the reaction vessel weighs 12.1 grams. What is the mass of carbon dioxide released during the reaction?
Element X forms three different compounds with element Y. Based on the information in this table.What are the formulas of compounds 2 and 3? 
Automobile airbags inflate due to the formation of nitrogen gas from the following chemical reaction. 2NaN3 (s) → 3N2 (g) + 2Na (s) Identify the number of each atom in the reactants and products for this balanced reaction. 
Convert the following quantities.6.80 x 1027 P4O10 molecules = 4.077 × 1020 formula units PbCl4 =
Two samples of sodium chloride were decomposed into their constituent elements. One sample produced 2.94 g of sodium and 4.53 g of chlorine. Which of the following could be the results of the decomposition of the other sample, being consistent with the law of constant composition (also called the law of definite proportions or law of definite composition)? a. 5.90 g of sodium and 3.54 g of chlorine b. 5.90 g of sodium and 1.47 g of chlorinec. 5.90 g of sodium and 14.8 g of chlorine d. 5.90 g of sodium and 9.09 g of chlorine