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What is the approximate mass of a proton?*
An electron in a sodium atom gains enough energy to move from the second shell to the third shell. The sodium atom becomes*
Which particle has no charge?*
Which quantity represents the number of protons in an atom?*
The element sulfur is classified as a*
The elements in Group 2 have similar chemical properties because each atom of these elements has the same*
What is formed when two atoms of bromine bond together?*
Gold can be flattened into an extremely thin sheet. The malleability of gold is due to the*
Which term represents the attraction one atom has for the electrons in a bond with another atom?*
Salt water is classified as a*
Which substance can not be broken down by a chemical change?*
Some physical properties of two samples of iodine-127 at two different temperatures are shown in the table below.
These two samples are two different*
Powdered iron is magnetic, but powdered sulfur is not. What occurs when they form a mixture in a beaker at room temperature?*
Which property is a measure of the average kinetic energy of the particles in a sample of matter?*
According to the kinetic molecular theory, which statement describes the particles of an ideal gas?*
The concentration of a solution can be expressed in*
Two hydrogen atoms form a hydrogen molecule when*
Which type of formula represents the simplest whole-number ratio of atoms of the elements in a compound?*
The coefficients in a balanced chemical equation represent*
Systems in nature tend to undergo changes toward*
Which formula represents an organic compound?*
Which class of organic compounds contains nitrogen?*
Which term identifies a type of organic reaction?*
Which compound is classified as a hydrocarbon?*
In an oxidation-reduction reaction, the number of electrons lost is*
Which substance is an electrolyte?*
Which energy conversion must occur in an operating electrolytic cell?*
Which compound yields H+ ions as the only positive ions in an aqueous solution?*
Which statement describes the relative masses of two different particles?*
Which term represents a type of nuclear reaction?*
Which ion has the smallest radius?*
Equal amounts of ethanol and water are mixed at room temperature and at 101.3 kPa. Which process is used to separate ethanol from the mixture?*
A sample of a substance has these characteristics: (cid:129) melting point of 984 K (cid:129) hard, brittle solid at room temperature (cid:129) poor conductor of heat and electricity as a solid (cid:129) good conductor of electricity as a liquid or in
an aqueous solution
This sample is classified as*
Given the balanced equation representing a reaction:
N2 + energy → N + N
Which statement describes this reaction?*
When lithium reacts with bromine to form the compound LiBr, each lithium atom*
A beaker with water and the surrounding air are all at 24°C. After ice cubes are placed in the water, heat is transferred from*
A sample of chlorine gas is at 300. K and 1.00 atmosphere. At which temperature and pressure would the sample behave more like an ideal gas?*
When a sample of a gas is heated in a sealed, rigid container from 200. K to 400. K, the pressure exerted by the gas is*
The bright-line spectra produced by four elements are represented in the diagram below.
Given the bright-line spectrum of a mixture formed from two of these elements:
Which elements are present in this mixture?*
The graph below represents the relationship between time and temperature as heat is added at a constant rate to a sample of a substance.
During interval AB, which energy change occurs for the particles in this sample?*
Given the potential energy diagram for a reversible chemical reaction:
Each interval on the axis labeled “Potential Energy (kJ/mol)” represents 10. kilojoules per mole. What is the activation energy of the forward reaction?*
Which condensed structural formula represents an unsaturated compound?*
Which element reacts spontaneously with 1.0 M HCl(aq) at room temperature?*
Given the balanced ionic equation:
3Pb2+(aq) + 2Cr(s) → 3Pb(s) + 2Cr3+(aq)
What is the number of moles of electrons gained by 3.0 moles of lead ions?*
What is the amount of heat energy released when 50.0 grams of water is cooled from 20.0°C to 10.0°C?*
What occurs at one of the electrodes in both an electrolytic cell and a voltaic cell?*
H2O(ℓ) + HCl(g) → H3O+(aq) + Cl−(aq)
According to one acid-base theory, the H2O(ℓ) molecules*
When an atom of the unstable isotope Na-24 decays, it becomes an atom of Mg-24 because the Na-24 atom spontaneously releases*
Which balanced equation represents nuclear fusion?*
Which reaction releases the greatest amount of energy per kilogram of reactants?*
Base your answers to questions 51 through 54 on the information below and on your knowledge of chemistry.
The diagram below represents three elements in Group 13 and three elements in Period 3 and their relative positions on the Periodic Table.
Some elements in the solid phase exist in different forms that vary in their physical properties. For example, at room temperature, red phosphorus has a density of 2.16 g/cm3 and white phosphorus has a density of 1.823 g/cm3.
Identify the element from the diagram that will react with chlorine to form a compound with the general formula XCl4.*
Consider the Period 3 elements in the diagram in order of increasing atomic number. State the trend in electronegativity for these elements.*
Compare the number of atoms per cubic centimeter in red phosphorus with the number of atoms per cubic centimeter in white phosphorus.*
Identify one element from the diagram that will combine with phosphorus in the same ratio of atoms as the ratio in aluminum phosphide.*
Base your answers to questions 55 through 57 on the information below and on your knowledge of chemistry.
The compounds KNO3 and NaNO3 are soluble in water.
Compare the entropy of 30. grams of solid KNO3 at 20.°C with the entropy of 30. grams of KNO3 dissolved in 100. grams of water at 20.°C.*
Explain why the total thermal energy of a sample containing 22.2 grams of NaNO3 dissolved in 200. grams of water at 20.°C is greater than the total thermal energy of a sample containing 11.1 grams of NaNO3 dissolved in 100. grams of water at 20.°C.*
Compare the boiling point of a NaNO3 solution at standard pressure to the boiling point of water at standard pressure.*
Base your answers to questions 58 through 61 on the information below and on your knowledge of chemistry.
Ethene and hydrogen can react at a faster rate in the presence of the catalyst platinum. The equation below represents a reaction between ethene and hydrogen.
Determine the molar mass of the product.*
State the number of electrons shared between the carbon atoms in one molecule of the reactant ethene.*
Explain, in terms of activation energy, why the catalyzed reaction occurs at a faster rate.*
Explain why the reaction is classified as an addition reaction.*
Base your answers to questions 62 and 63 on the information below and on your knowledge of chemistry.
In a titration, 50.0 milliliters of 0.026 M HCl(aq) is neutralized by 38.5 milliliters of KOH(aq).
Show a numerical setup for calculating the molarity of the KOH(aq).*
Complete the equation below for the neutralization by writing the formula of the missing product.
Base your answers to questions 64 and 65 on the information below and on your knowledge of chemistry.
Table sugar, sucrose, is a combination of two simple sugars, glucose and fructose. The formulas below represent these simple sugars.
Identify the functional group that appears more than once in the fructose molecule.*
Explain, in terms of atoms and molecular structure, why glucose and fructose are isomers of each other.*
Base your answers to questions 66 through 70 on the information below and on your knowledge of chemistry.
Baking soda, NaHCO3, can be commercially produced during a series of chemical reactions called the Solvay process. In this process, NH3(aq), NaCl(aq), and other chemicals are used to produce NaHCO3(s) and NH4Cl(aq).
To reduce production costs, NH3(aq) is recovered from NH4Cl(aq) through a different series of reactions. This series of reactions can be summarized by the overall reaction represented by the unbalanced equation below.
NH4Cl(aq) + CaO(s) → NH3(aq) + H2O(ℓ) + CaCl2(aq)
Write a chemical name for baking soda.*
Determine the percent composition by mass of carbon in baking soda (gram-formula mass = 84 grams per mole).*
State the color of bromcresol green in a sample of NH3(aq).*
Determine the mass of NH4Cl that must be dissolved in 100. grams of H2O to produce a saturated solution at 70.°C.*
Balance the equation below for the overall reaction used to recover NH3(aq), using the smallest whole-number coefficients.
Base your answers to questions 71 through 75 on the information below and on your knowledge of chemistry.
Rubbing alcohol is a product available at most pharmacies and supermarkets. One rubbing alcohol solution contains 2-propanol and water. The boiling point of 2-propanol is 82.3°C at standard pressure.
Explain, in terms of electronegativity differences, why a C O bond is more polar than a C H bond.*
Identify a strong intermolecular force of attraction between an alcohol molecule and a water molecule in the solution.*
Determine the vapor pressure of water at a temperature equal to the boiling point of the 2-propanol.*
Explain, in terms of charge distribution, why a molecule of the 2-propanol is a polar molecule.*
Draw a structural formula for the 2-propanol.*
Base your answers to questions 76 and 77 on the information below and on your knowledge of chemistry.
Silver-plated utensils were popular before stainless steel became widely used to make eating utensils. Silver tarnishes when it comes in contact with hydrogen sulfide, H2S, which is found in the air and in some foods. However, stainless steel does not tarnish when it comes in contact with hydrogen sulfide.
Draw a Lewis electron-dot diagram for the compound that tarnishes silver.*
In the ground state, an atom of which noble gas has the same electron configuration as the sulfide ion in Ag2S?*
Base your answers to questions 78 through 81 on the information below and on your knowledge of chemistry.
Common household bleach is an aqueous solution containing hypochlorite ions. A closed container of bleach is an equilibrium system represented by the equation below.
Cl2(g) + 2OH−(aq) ⇌ ClO−(aq) + Cl−(aq) + H2O(ℓ)
Compare the rate of the forward reaction to the rate of the reverse reaction for this system.*
State the change in oxidation number for chlorine when the Cl2(g) changes to Cl−(aq) during the forward reaction.*
Explain why the container must be closed to maintain equilibrium.*
State the effect on the concentration of the ClO− ion when there is a decrease in the concentration of the OH− ion.*
Base your answers to questions 82 through 85 on the information below and on your knowledge of chemistry.
Iodine has many isotopes, but only iodine-127 is stable and is found in nature. One radioactive iodine isotope, I-108, decays by alpha particle emission. Iodine-131 is also radioactive and has many important medical uses.
Determine the number of neutrons in an atom of I-127.*
Explain, in terms of protons and neutrons, why I-127 and I-131 are different isotopes of iodine.*
Complete the equation below for the nuclear decay of I-108.
Determine the total time required for an 80.0-gram sample of I-131 to decay until only 1.25 grams of the sample remains unchanged.*