Chem PART 2
voltage at standard conditions
1 M, 1 atm, 25 C
Which of the following condition(s) is/are met at the equivalence point of the titration of a monoprotic weak base with a strong acid? 1. The number of moles of acid added from the burette equals the initial number of moles of the weak base. 2. The volume of acid added from the buret equals the volume of the base titrated. 3. The pH of the solution is greater than 7.00. 1 only 2 only 3 only 1 and 3
1 only
Which of the following factors are likely to affect the rate of a chemical reaction? 1. the presence of a catalyst 2. the temperature of the reactants 3. the physical state (solid, liquid, or gas) of the reactants 1 only 2 only 3 only 1, 2, and 3
1,2,3
Kinetic Molecular Theory
1. Gases consist of large number of molecules that are in constant, random motion 2. Gases are mostly empty space. The combined volume of all the molecules is negligible relative to total volume 3. Gas molecules don't stick to each other when they collide. Attractive and repulsive forced between molecules are negligible. Collisions between molecules are elastic 4. Gas pressure is caused by collisions of molecules 5. Average kinetic energy of molecules is proportional only to the temperature
What is the H3O+ concentration in a 0.66 M NH4+(aq) solution? (Ka of NH4+ = 5.6 × 10-10) 3.7 × 10-10 M 8.5 × 10-10 M 1.9 × 10-5 M 2.4 × 10-5 M
1.9 × 10-5 M
What is the voltage of the standard automobile battery? 1.5 V 6 V 50 V 12 V
12V
Where does oxidation take place in an electrochemical cell? the anode and the cathode the cathode the anode the half cell
Anode
The ideal gas law combines Boyle's law, Charles's law, Gay-Lussac's law and ________. Graham's law Avogadro's law Raoult's law Dalton's law
Avogadro's law
The ideal gas law combines Avogadro's law, Charles's law, Gay-Lussac's law and ________. Graham's law Boyle's law Raoult's law Dalton's law
Boyle's law
Ignoring the cost of materials, which of the following substances, all used at the same concentration (molality), would you expect to be the most efficient at melting snow on a road? (For your convenience we have attached to this assessment a page containing a table of common boiling and freezing temperatures and the relevant boiling- and freezing-point equations.) sugar CaCl2 NH4Cl MgSO4
CaCl2
To convert a sample of air into a liquid as done commercially to produce liquid nitrogen, and hat would you probably have to do?
Decrease T and increase P
strong acids
HCl HBr HI HNO3 NClO4 H2SO4
rate of effusion
Less mass= more speed
Strong Bases
Li to Cs and Ca to Ba
Higher elevation makes air pressure do what?
Makes air pressure lower so boiling point is lower
Which instrument measures the pressure of an enclosed gas?
Manometer
What is a phase change directly from solid to gas called?
Sublimation
Water vapor pressure depends on which of the following?
Temperature of the water
Why does the air pressure inside the tires of a car increase when the car is driven? Some of the air has leaked out. The air particles collide with the tire after the car is in motion. The air particles inside the tire increase their speed because their temperature rises. The atmosphere compresses the tire.
The air particles inside the tire increase their speed because their temperature rises.
Which statement is true for a reaction at equilibrium? The forward reaction rate is lower than the reverse reaction rate. The forward reaction rate is higher than the reverse reaction rate. The forward reaction rate is equal to the reverse reaction rate. No reactions take place.
The forward reaction rate is equal to the reverse reaction rate.
Temperature is a measure of what?
The kinetic energy of molecules
The temperature and pressure at which a substance has all three states of matter in equilibrium is referred to as what?
The triple point
Why does a can collapse when a vacuum pump removes air from the can?
The unbalanced outside force from atmospheric pressure crushes the can.
Which statement is true for the electrodes in a zinc-carbon dry cell? The zinc electrode is the anode and the carbon electrode is the cathode. The zinc electrode is the cathode and the carbon electrode is the anode. Both electrodes are auto-oxidizing and serve as both cathodes and anodes. Neither electrode can be considered a cathode or an anode.
The zinc electrode is the anode and the carbon electrode is the cathode.
How are the exponents in a rate law determined? They are equal to 1 for gas phase reactants and 0 for solid phase reactants. They are determined by experimentation. They are equal to the coefficients in the overall balanced chemical equation. They are equal to the reactant concentrations.
They are determined by experimentation
Why do acid-base indicators change colors? They are weak acids and change colors when the hydrogen is removed from the indicator molecule. They are weak acids and change colors when the hydrogen is added to the indicator molecule. They are strong acids and change colors when the hydrogen is added to the indicator molecule. They are strong acids and change colors when the hydrogen is removed from the indicator molecule.
They are weak acids and change colors when the hydrogen is removed from the indicator molecule.
Dalton's Law
Total pressure of a gas= sum of individual pressures
average velocity of a gas molecule
Urms- formula
What does Charles' Law state?
V directly proportional to temperature
What does Boyle's law state?
V inversely proportional to pressure
What is the gas pressure above a liquid at equilibrium called?
Vapor pressure
Avogadro's Law
Volume directly proportional to number of moles
When does the boiling point of a liquid occur?
When the vapor pressure of the liquid equals the atmospheric pressure
At what point in an acid-base titration are equivalent quantities of hydronium ions and hydroxide ions present? at the beginning point at the midpoint at the end point throughout the titration
at the end point
Which instrument measures atmospheric pressure?
barometer
In an acid-base titration, a(n) __________. base is always added to an acid acid is always added to a base base is added to an acid or an acid is added to a base none of these
base is added to an acid or an acid is added to a base
Two gases have the same temperature but different pressures. The kinetic-molecular theory does not predict that ________. molecules in both gases have the same average kinetic energies molecules in the lower-pressure gas travel farther before they collide with other molecules both gases have the same densities all collisions of the molecules are elastic
both gases have the same densities
Which of the following relationships is/are true for gases? a. The moles of a gas is inversely proportional to its volume (at constant pressure). b. The volume of a gas is inversely proportional to its temperature in kelvin (at constant pressure). c. The pressure of a gas is directly proportional to its temperature in kelvin (at constant volume) a only b only c only a and b
c only
Which process is used to speed up chemical reactions? calorimetry catalysis activation inhibition
catalysis
What is the name given to a substance that increases the rate of a chemical reaction but is not itself consumed? catalyst reactant rate constant product
catalyst
In a voltaic cell with electrodes made from zinc and copper, the copper has additional copper metal plate out on its surface. The copper electrode is called the __________. cathode. metal electrode anode reducing electrode
cathode
Where does reduction take place in an electrochemical cell? the half cell the anode the cathode the anode and the cathode
cathode
What is happening when an automobile battery is starting a car? Energy as heat is converted to energy of motion. Energy of motion is converted to energy as heat. Electrical energy is converted to chemical energy. Chemical energy is converted to electrical energy.
chemical energy converts to electrical energy
What is happening when a AA battery powers a wireless computer mouse? Energy as heat is converted to energy of motion. Energy of motion is converted to energy as heat. Chemical energy is converted to electrical energy. Electrical energy is converted to chemical energy.
chemical energy is converted to electrical energy
What is happening when an automobile battery is starting a car? Energy as heat is converted to energy of motion. Energy of motion is converted to energy as heat. Chemical energy is converted to electrical energy. Electrical energy is converted to chemical energy.
chemical energy is converted to electrical energy
Which model attempts to explain chemical reactions and physical interactions of molecules? chemical kinetics thermodynamics collision theory thermochemistry
collision theory
What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide? colorless to pink pink to colorless green to yellow yellow to blue
colorless to pink
What unknown quantity can be calculated after performing a titration? volume concentration mass density
concentration
While the pressure stays constant, the temperature of a gas is decreased from 90°C to 30°C. The volume will ____________. triple decrease by 1/3 decrease by about 17% remain the same
decrease by about 17%
All monatomic ions have oxidation numbers equal to the __________. difference of protons and electrons number of protons number of electrons difference of protons and neutrons
difference of proton and electrons
What is happening when an automobile battery is charging? Energy of motion is converted to energy as heat. Electrical energy is converted to chemical energy. Energy as heat is converted to energy of motion. Chemical energy is converted to electrical energy.
electrical energy is converted to chemical energy
If the reactants in a spontaneous, energy-releasing redox reaction are connected externally by a wire conductor, what form is the energy released as? light heat movement electricity
electricity
In which system does a spontaneous redox reaction produce electrical energy? electroplating cell electrochemical cell electrolytic cell half cell
electrochemical cell
At a given temperature, molecules of different gases ________. have the same average kinetic energy of translational motion have the same diameter have the same density have identical masses
have the same average kinetic energy of translational motion
While the pressure stays constant, the temperature of a gas is increased from 40°C to 160°C. The volume will ____________. quadruple decrease by 1/4 increase by about 40% remain the same
increase by about 40%
Raising the temperature of reactants in a system ___________. increases the average molecular motion decreases the average molecular motion has no effect on the average molecular motion disturbs the system so that the collision theory no longer applies
increases the average molecular motion
A substance with a very small Ksp is ________. insoluble or sparingly soluble very soluble moderately soluble completely miscible in most solvents
insoluble or sparingly soluble
The average velocity of a gas molecule is __________. directly proportional to the square of its temperature in °C inversely proportional to the gas constant, R inversely proportional to the square root of its molar mass (MW) inversely proportional to its kinetic energy
inversely proportional to the square root of its molar mass (MW)
How is the oxidation number affected in an anode reaction? it decreases it increases it does not change none of the above
it increases
If the temperature of a fixed quantity of gas decreases and the pressure remains unchanged, then ________. its volume increases its volume is unchanged its volume decreases its density decreases
its volume decreases
If the temperature of a fixed quantity of gas increases and the pressure decreases, then ________. its volume decreases its volume is unchanged its volume increases its density decreases
its volume increases
Which substances react in a standard automobile battery? lead (IV) oxide, lead, and sulfuric acid zinc oxide, zinc, and sulfuric acid iron (III) oxide, iron, and sulfuric acid copper (II) oxide, copper, and sulfuric acid
lead (IV) oxide, lead, and sulfuric acid
The addition of any solute to a solvent will do what? lower the vapor pressure and increase the osmotic pressure lower the vapor pressure and decrease the osmotic pressure raise the vapor pressure and increase the osmotic pressure raise the vapor pressure and decrease the osmotic pressure
lower the vapor pressure and increase the osmotic pressure
When pressure, volume, and temperature are known, what can the ideal gas law be used to calculate? the chemical formula the universal gas constant molar amount rate of effusion
molar amount
polyprotic acids
more than 1 hydrogen is ionizable
What kind of reaction does an acid-base titration involve? composition reaction neutralization reaction single-displacement reaction decomposition reaction
neutralization reaction
Besides the Ksp value of a compound, what other information is needed to calculate solubility in moles per liter? molar mass solubility in grams density of the solid no other information
no other information
uring an acid-base titration, a very rapid change in pH ____________. occurs when the amounts of H3O+ ions and OH- ions are nearly equivalent occurs when the first addition of the known solution is made occurs at several points during the titration does not occur during titration
occurs when the amounts of H3O+ ions and OH- ions are nearly equivalent
In a zinc dry cell, which is true of the oxidation process? oxidation of zinc occurs at the cathode oxidation of manganese occurs at the anode oxidation of zinc occurs at the anode manganese occurs at the cathode
oxidation of zinc occurs at the anode
An acid-base titration is carried out by monitoring ___________. temperature pH pressure density
pH
Which statement is true for positive ions in an electrochemical cell? Positive ions become negative ions. Positive ions do not move. Positive ions move toward the cathode. Positive ions move toward the anode.
positive ions move towards cathode
If the temperature of a fixed quantity and volume of gas changes, what also changes? pressure density mass the formula
pressure
In the Virtual Chem Lab assignment, Oxidation-Reduction Titrations, what was the color of the permanganate solution which filled the burette? yellow purple green light blue
purple
What is the gain of electrons called? oxidation reduction electrochemistry half-reaction
reduction
Which of the following best describes how bases feel? rough slippery moist dry
slippery
The product of a precipitation reaction is always a(n) ________. liquid gas aqueous solution solid
solid
Which of the following best describes how acids taste? sweet bitter sour salty
sour
To correct for the partial pressure of water vapor in a gas collection bottle, the vapor pressure of H2O at the collecting temperature is generally __________. subtracted from the atmospheric pressure subtracted from the partial pressure of the collected gas added to the atmospheric pressure added to the pressure of the collected gas
subjected from the atmospheric pressure
Pressure is the force per unit of what
surface area
The value of R, the universal gas constant, can be calculated from measured values of gas's pressure, volume, molar amount, and which of the following? temperature chemical formula rate of diffusion density
temperature
In an electrochemical cell, the anode is which of the following? the electrode at which matter gains electrons the electrode at which matter loses electrons the neutral electrode the electrode at which matter can gain or lose electrons
the electrode at which matter loses electrons
A reaction is second order for reactant A and first order for reactant B. What happens to the reaction rate when the concentrations of both reactants are doubled? The reaction rate remains the same. The reaction rate increases by a factor of two. The reaction rate increases by a factor of four. The reaction rate increases by a factor of eight.
the reaction rate increases by a factor of eight
What process measures the amount of a solution of known concentration required to react with a measured amount of a solution of unknown concentration? autoprotolysis neutralization hydrolysis titration
titration
The value of k in a rate law________. is the same under all conditions varies with concentration varies with time varies with temperature
varies with temperature
What quantity is directly measured in a titration? mass concentration volume density
volume
Neutralization
when acids and bases react to form salt and water
In a zinc dry cell, three sides of the casing are made of which metal? zinc gold chromium nickel
zinc
