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Compared to an electron, which particle has a charge that is equal in magnitude but opposite in sign?*
The mass of a proton is approximately equal to*
Which property decreases when the elements in Group 17 are considered in order of increasing atomic number?*
Any substance composed of two or more elements that are chemically combined in a fixed proportion is*
Which term refers to how strongly an atom of an element attracts electrons in a chemical bond with an atom of a different element?*
At STP, which substance has metallic bonding?*
What is the number of electrons shared between the carbon atoms in a molecule of ethyne?*
Which atom in the ground state has a stable valence electron configuration?*
What occurs when two fluorine atoms react to produce a fluorine molecule?*
Which gas sample at STP has the same number of molecules as a 2.0-liter sample of Cl2(g) at STP?*
All atoms of uranium have the same*
The concentration of a solution can be expressed in*
Compared to the boiling point and the freezing point of water at 1 atmosphere, a 1.0 M CaCl2(aq) solution at 1 atmosphere has a*
According to the kinetic molecular theory, which statement describes an ideal gas?*
Which physical change is endothermic?*
Which Group 16 element combines with hydrogen to form a compound that has the strongest hydrogen bonding between its molecules?*
Hydrocarbons are composed of the elements*
Which atom is bonded to the carbon atom in the functional group of a ketone?*
Two types of organic reactions are*
The isomers butane and methylpropane have*
In a redox reaction, which particles are lost and gained in equal numbers?*
What is the oxidation state for a Mn atom?*
Which compounds are classified as electrolytes?*
Which compound is an Arrhenius base?*
According to one acid-base theory, a water molecule acts as a base when it accepts*
Given the equation representing a system at equilibrium:
N2(g) + 3H2(g) ⇌ 2NH3(g)
Which statement describes this reaction at equilibrium?*
The acidity or alkalinity of an unknown aqueous solution is indicated by its*
The laboratory process in which the volume of a solution of known concentration is used to determine the concentration of another solution is called*
Which list of nuclear emissions is arranged in order from the greatest penetrating power to the least penetrating power?*
Given the diagram representing a reaction:
Which type of change is represented?*
Which electron shell contains the valence electrons of a radium atom in the ground state?*
Each diagram below represents the nucleus of an atom.
How many different elements are represented by the diagrams?*
Chlorine and element X have similar chemical properties. An atom of element X could have an electron configuration of*
Which group of elements contains a metalloid?*
Which Lewis electron-dot diagram represents a fluoride ion?*
In the formula for the compound XCl4, the X could represent*
The formula C2H4 can be classified as*
Given the balanced equation representing a reaction:
4Al(s) + 3O2(g) → 2Al2O3(s)
How many moles of Al(s) react completely with 4.50 moles of O2(g) to produce 3.00 moles of Al2O3(s)?*
What is the percent composition by mass of oxygen in Ca(NO3)2 (gram-formula mass = 164 g/mol)?*
6Li + N2 → 2Li3N
Which type of chemical reaction is represented by this equation?*
Which elements can react to produce a molecular compound?*
Compared to a 1.0-mole sample of NaCl(s), a 1.0-mole sample of NaCl(ℓ) has a different*
Which property of an unsaturated solution of sodium chloride in water remains the same when more water is added to the solution?*
Which ion combines with Ba2+ to form a compound that is most soluble in water?*
When a sample of gas is cooled in a sealed, rigid container, the pressure the gas exerts on the walls of the container will decrease because the gas particles hit the walls of the container*
A rigid cylinder with a movable piston contains 50.0 liters of a gas at 30.0°C with a pressure of 1.00 atmosphere. What is the volume of the gas in the cylinder at STP?*
Given the potential energy diagram for a chemical reaction:
Which numbered interval represents the heat of reaction?*
Base your answers to questions 48 and 49 on the graph below and on your knowledge of chemistry.
What is represented by the number “1” in the IUPAC name for three of these alcohols?*
What can be concluded from this graph?*
In the laboratory, a student investigates the effect of concentration on the reaction between HCl(aq) and Mg(s), changing only the concentration of HCl(aq). Data for two trials in the investigation are shown in the table below.
Compared to trial 1, what is the expected reaction time for trial 2 and the explanation for that result?*
Determine the volume of 2.00 M HCl(aq) solution required to completely neutralize 20.0 milliliters of 1.00 M NaOH(aq) solution.*
Determine the mass of KNO3 that dissolves in 100. grams of water at 40.°C to produce a saturated solution.*
State, in terms of molecular polarity, why ethanol is soluble in water.*
Base your answers to questions 54 through 56 on the information below and on your knowledge of chemistry.
Three elements, represented by D, E, and Q, are located in Period 3. Some properties of these elements are listed in the table below. A student’s experimental result indicates that the density of element Q is 2.10 g/cm3, at room temperature and standard pressure.
Identify the physical property in the table that could be used to differentiate the samples of the three elements from each other.*
Identify the group on the Periodic Table to which element D belongs.*
Determine the percent error between the student’s experimental density and the accepted density of element Q.*
Base your answers to questions 57 through 59 on the information below and on your knowledge of chemistry.
The equation below represents an equilibrium system of SO2(g), O2(g), and SO3(g). The reaction can be catalyzed by vanadium or platinum.
2SO2(g) + O2(g) ⇌ 2SO3(g) + energy
Compare the rates of the forward and reverse reactions at equilibrium.*
State how the equilibrium shifts when SO3(g) is removed from the system.*
A potential energy diagram for the forward reaction is shown below. On this diagram, draw a dashed line to show how the potential energy changes when the reaction occurs by the catalyzed pathway.
Base your answers to questions 60 and 61 on the information below and on your knowledge of chemistry.
The formulas for two compounds are shown below.
Explain, in terms of bonding, why compound A is saturated.*
Explain, in terms of molecular structure, why the chemical properties of compound A are different from the chemical properties of compound B.*
Base your answers to questions 62 through 65 on the information below and on your knowledge of chemistry.
Some isotopes of potassium are K-37, K-39, K-40, K-41, and K-42. The natural abundance and the atomic mass for the naturally occurring isotopes of potassium are shown in the table below.
Identify the decay mode of K-37.*
Complete the nuclear equation below for the decay of K-40 by writing a notation for the missing nuclide.
Determine the fraction of an original sample of K-42 that remains unchanged after 24.72 hours.*
Show a numerical setup for calculating the atomic mass of potassium.*
Base your answers to questions 66 through 68 on the information below and on your knowledge of chemistry.
The Bohr model of the atom was developed in the early part of the twentieth century. A diagram of the Bohr model for one atom, in the ground state, of a specific element is shown below. The nucleus of this atom contains 4 protons and 5 neutrons.
State the atomic number and the mass number of this element.*
State the number of electrons in each shell in this atom in the ground state.*
Using the Bohr model, describe the changes in electron energy and electron location when an atom changes from the ground state to an excited state.*
Base your answers to questions 69 through 72 on the information below and on your knowledge of chemistry.
In 1828, Friedrich Wöhler produced urea when he heated a solution of ammonium cyanate. This reaction is represented by the balanced equation below.
Identify the element in urea that makes it an organic compound.*
Determine the gram-formula mass of the product.*
Write an empirical formula for the product.*
Explain why this balanced equation represents a conservation of atoms.*
Base your answers to questions 73 through 75 on the information below and on your knowledge of chemistry.
Rubbing alcohol sold in stores is aqueous 2-propanol, CH3CHOHCH3(aq). Rubbing alcohol is available in concentrations of 70.% and 91% 2-propanol by volume.
To make 100. mL of 70.% aqueous 2-propanol, 70. mL of 2-propanol is diluted with enough water to produce a total volume of 100. mL. In a laboratory investigation, a student is given a 132-mL sample of 91% aqueous 2-propanol to separate using the process of distillation.
State evidence that indicates the proportions of the components in rubbing alcohol can vary.*
Identify the property of the components that makes it possible to use distillation to separate the 2-propanol from water.*
Determine the maximum volume of 2-propanol in the 132-mL sample.*
Base your answers to questions 76 through 79 on the information below and on your knowledge of chemistry.
A sample of seawater is analyzed. The table below gives the concentration of some ions in the sample.
Write a chemical formula of one compound formed by the combination of K+ ions with one of these ions as water completely evaporates from the seawater sample.*
Determine the number of moles of the SO42− ion in a 1400.-liter sample of the seawater.*
Compare the radius of an Mg2+ ion in the seawater to the radius of an Mg atom.*
Using the key below, draw two water molecules in the box, showing the orientation of each water molecule toward the calcium ion.
Base your answers to questions 80 through 82 on the information below and on your knowledge of chemistry.
A scientist bubbled HCl(g) through a sample of H2O(ℓ). This process is represented by the balanced equation below.
H2O(ℓ) + HCl(g) → H3O+(aq) + Cl−(aq)
The scientist measured the pH of the liquid in the flask before and after the gas was bubbled through the water. The initial pH value of the water was 7.0 and the final pH value of the solution was 3.0.
Explain, in terms of ions, why the gaseous reactant in the equation is classified as an Arrhenius acid.*
What would be the color of bromcresol green if it had been added to the water in the flask before any of the HCl(g) was bubbled through the water?*
Compare the hydronium ion concentration of the solution that has the pH value of 3.0 to the hydronium ion concentration of the water.*
Base your answers to questions 83 through 85 on the information below and on your knowledge of chemistry.
A small digital clock can be powered by a battery made from two potatoes and some household materials. The “potato clock” battery consists of two cells connected in a way to produce enough electricity to allow the clock to operate. In each cell, zinc atoms react to form zinc ions. Hydrogen ions from phosphoric acid in the potatoes react to form hydrogen gas. The labeled diagram and balanced ionic equation below show the reaction, the materials, and connections necessary to make a “potato clock” battery.
State the direction of electron flow in wire A as the two cells operate.*
Write a balanced half-reaction equation for the oxidation that occurs in the “potato clock” battery.*
Explain why phosphoric acid is needed for the battery to operate.*