A weather balloon with a 2-meter diameter at ambient temperature holds 525 grams of helium. What type of electronic probe could be used to determine the pressure inside the balloon?
barometric
thermometric
calorimetric
spectrophotometric
Which would be most appropriate for collecting data during a neutralization reaction?
a pH probe
a statistics program
a thermometer
a graphing program
A scientist observed changes in the gas pressure of one mole of a gas in a sealed chamber with a fixed volume. To identify the source of the changes, the scientist should check for variations in the
air pressure outside the chamber.
molecular formula of the gas.
temperature of the chamber.
isotopes of the gas.
Electrical fires cannot be safely put out by dousing them with water. However, fire extinguishers that spray solid carbon dioxide on the fire work very effectively. This method works because carbon dioxide
displaces the oxygen.
renders the fire’s fuel non-flammable.
forms water vapor.
blows the fire out with strong wind currents.
In the cubic crystal shown, if each edge is 2.0 angstroms in length, what is the diagonal distance, d, between atoms 1 and 3? (Assume that the Pythagorean theorem can be used to solve this problem.)
2.5 Å
Å
Å
Å
In order to advance to the level of a theory, a hypothesis should be
obviously accepted by most people.
a fully functional experiment.
in alignment with past theories.
repeatedly confirmed by experimentation.
Matter is made of atoms that have positive centers of neutrons and protons surrounded by a cloud of negatively charged electrons. This statement is
a theory.
a hypothesis.
an inference.
an observation.
The model of ideal gases shown above is useful because it
accurately approximates the properties of most gas molecules.
predicts the behavior of other phases of matter.
gives precise explanations for nonideal gas behavior.
shows a linear relation between gas pressure and volume.
When a metal is heated in a flame, the flame has a distinctive color. This information was eventually extended to the study of stars because
the color spectra of stars indicate which elements are present.
a red shift in star color indicates stars are moving away.
star color indicates absolute distance.
it allows the observer to determine the size of stars.
Which of the following ordered pairs of elements shows an increase in atomic number but a decrease in average atomic mass?
Ag to Pd
Co to Ni
Ge to Sn
Cr to Mo
Why is cobalt (Co) placed before nickel (Ni) on the periodic table of the elements even though it has a higher average atomic mass than nickel?
Nickel has one more proton.
Cobalt was discovered first.
Nickel has fewer electrons.
Cobalt has a lower density.
Generally, how do atomic masses vary throughout the periodic table of the elements?
They increase from left to right and top to bottom.
They increase from left to right and bottom to top.
They increase from right to left and top to bottom.
They increase from right to left and bottom to top.
Iodine would have chemical properties most like
manganese (Mn).
tellurium (Te).
chlorine (Cl).
xenon (Xe).
Which of the following elements is classified as a metal?
bromine
helium
sulfur
lithium
The chart above shows the relationship between the first ionization energy and the increase in atomic number. The letter on the chart for the alkali family of elements is
W
X
Y
Z
Which of the following atoms has the largest atomic radius?
barium (Ba)
chlorine (Cl)
iodine (I)
magnesium (Mg)
Which of the following atoms has six valence electrons?
magnesium (Mg)
silicon (Si)
sulfur (S)
argon (Ar)
Which statement best describes the density of an atom’s nucleus?
The nucleus occupies most of the atom’s volume but contains little of its mass.
The nucleus occupies very little of the atom’s volume and contains little of its mass.
The nucleus occupies most of the atom’s volume and contains most of its mass.
The nucleus occupies very little of the atom’s volume but contains most of its mass.
What information do the experimental results above reveal about the nucleus of the gold atom?
The nucleus contains less than half the mass of the atom.
The nucleus is small and is the densest part of the atom.
The nucleus contains small positive and negative particles.
The nucleus is large and occupies most of the atom’s space.
Why are enormous amounts of energy required to separate a nucleus into its component protons and neutrons even though the protons in the nucleus repel each other?
The force of the protons repelling each other is small compared to the attraction of the neutrons to each other.
The electrostatic forces acting between other atoms lowers the force of repulsion of the protons.
The interactions between neutrons and electrons neutralize the repulsive forces between the protons.
The forces holding the nucleus together are much stronger than the repulsion between the protons.
The most abundant isotope of lead contains 82 protons and 124 neutrons packed closely together in the nucleus. Why do the protons stay together in the nucleus rather than fly apart?
Electrons in neighboring atoms neutralize repulsive forces between protons.
Neutrons effectively block the protons and keep them far apart to prevent repulsion.
Electrostatic forces between neutrons and protons hold the nucleus together.
Nuclear forces overcome repulsive forces between protons in the nucleus.
Which equation correctly represents the alpha decay of polonium-214?
A 2-cm-thick piece of cardboard placed over a radiation source would be most effective in protecting against which type of radiation?
alpha
beta
gamma
x-ray
Which of the following is a monatomic gas at STP?
chlorine
fluorine
helium
nitrogen
When cations and anions join, they form what kind of chemical bond?
ionic
metallic
hydrogen
covalent
Which of the following correctly shows how carbon and hydrogen bond to form a compound?
Some of the molecules found in the human body are NH2CH2COOH (glycine), C6H12O6 (glucose), and CH3(CH2)16COOH (stearic acid). The bonds they form are
nuclear
metallic
ionic
covalent
What type of bond do all of the molecules in the table above have in common?
covalent
ionic
metallic
polar
The reason salt crystals, such as KCl, hold together so well is because the cations are strongly attracted to
neighboring cations.
the protons in the neighboring nucleus.
free electrons in the crystals.
neighboring anions.
What type of force holds ions together in salts such as CaF2?
electrostatic
magnetic
gravitational
nuclear
Under the same conditions of pressure and temperature, a liquid differs from a gas because the molecules of the liquid
have no regular arrangement.
are in constant motion.
have stronger forces of attraction between them.
take the shape of the container they are in.
Which of the following elements has the same Lewis dot structure as silicon?
germanium (Ge)
aluminum (Al)
arsenic (As)
gallium (Ga)
Which substance is made up of many monomers joined together in long chains?
salt
protein
ethanol
propane
For the polymer, polyvinyl chloride,
(PVC), ~ CH2CH(Cl)CH2CH(Cl)CH2CH(Cl) ~
the repeating subunit is
CH(Cl)
CH(Cl)CHCH2.
CH2CH.
CH2CH(Cl).
Which element is capable of forming stable, extended chains of atoms through single, double, or triple bonds with itself?
carbon
oxygen
nitrogen
hydrogen
Proteins are large macromolecules composed of thousands of subunits. The structure of the protein depends on the sequence of
lipids.
monosaccharides.
amino acids.
nucleosides.
When a cold tire is inflated to a certain pressure and then is warmed up due to friction with the road, the pressure increases. This happens because the
air molecules hit the walls of the tire less frequently.
rubber in the tire reacts with oxygen in the atmosphere.
air molecules speed up and collide with the tire walls more often.
air molecules diffuse rapidly through the walls of the tire.
When someone standing at one end of a large room opens a bottle of vinegar, it may take several minutes for a person at the other end to smell it. Gas molecules at room temperature move at very high velocities, so what is responsible for the delay in detection of the vinegar?
the increase in the airspace occupied by vinegar molecules
the chemical reaction with nerves, which is slower than other sensory processes
attractive forces between the air and vinegar molecules
random collisions between the air and vinegar molecules
Methane (CH4) gas diffuses through air because the molecules are
moving randomly.
dissolving quickly.
traveling slowly.
expanding steadily
The volume of 400 mL of chlorine gas at 400 mm Hg is decreased to 200 mL at constant temperature. What is the new gas pressure?
400 mm Hg
300 mm Hg
800 mm Hg
650 mm Hg
Under what circumstance might a gas decrease in volume when heated?
The gas is held constant at STP.
The gas remains under uniform temperature.
The gas is placed under increasing pressure.
The gas undergoes a decrease in pressure.
A sample of carbon dioxide gas occupies a volume of 20 L at standard temperature and pressure (STP). What will be the volume of a sample of argon gas that has the same number of moles and pressure but twice the absolute temperature?
10 L
20 L
40 L
80 L
Standard temperature and pressure (STP) are defined as
0 °C and 1.0 atm pressure.
0 °C and 273 mm Hg pressure.
0 K and 1.0 atm pressure.
0 K and 760 mm Hg pressure.
Under which of the following sets of conditions will a 0.50 mole sample of helium occupy a volume of 11.2 liters?
298 K and 0.90 atm
273 K and 1.10 atm
373 K and 0.50 atm
273 K and 1.00 atm
What is the equivalent of 423 kelvin in degrees Celsius?
–223 °C
–23 °C
150 °C
696 °C
Theoretically, when an ideal gas in a closed container cools, the pressure will drop steadily until the pressure inside is essentially that of a vacuum. At what temperature should this occur?
0 °C
−460 °C
−273 K
0 K
The temperature at which all molecular motion stops is
−460 °C
−273 K.
0 K.
0 °C.
Which of the substances in the table can act as either the solute or the solvent when mixed with 100 grams of water at 20 °C?
NH3
C6H5COOH
MgCl2
CH3CH2OH
A teaspoon of dry coffee crystals dissolves when mixed in a cup of hot water. This process produces a coffee solution. The original crystals are classified as a
solute.
solvent.
reactant.
product.
If the attractive forces among solid particles are less than the attractive forces between the solid and a liquid, the solid will
probably form a new precipitate as its crystal lattice is broken and re-formed.
be unaffected because attractive forces within the crystal lattice are too strong for the dissolution to occur.
begin the process of melting to form a liquid.
dissolve as particles are pulled away from the crystal lattice by the liquid molecules.
Water is a polar solvent, while hexane is a nonpolar solvent.Which of the examples above illustrates a nonpolar solute in a polar solvent?
NH4Cl in water
C10H8 in water
C2H5OH in hexane
CO(NH2)2 in hexane
A technician prepared a solution by heating 100 milliliters of distilled water while adding KCl crystals until no more KCl would dissolve. She then capped the clear solution and set it aside on the lab bench. After several hours she noticed the solution had become cloudy and some solid had settled to the bottom of the flask. Which statement best describes what happened?
As the solution cooled, evaporation of water increased the KCl concentration beyond its solubility.
Water molecules, trapped with the KCl crystals, were released after heating.
At lower temperatures the solubility of the KCl decreased and recrystallization occurred.
At increased temperatures the solubility of KCl increased and remained too high after cooling.
If the solubility of NaCl at 25 °C is 36.2 g/100 g H2O, what mass of NaCl can be dissolved in 50.0 g of H2O?
18.1 g
36.2 g
72.4 g
86.2 g
How many moles of HNO3 are needed to prepare 5.0 liters of a 2.0 M solution of HNO3?
2.5
5
10
20
The Dead Sea is the saltiest sea in the world. It contains 332 grams of salt per 1000 grams of water. What is the concentration in parts per million (ppm)?
0.332 ppm
332 ppm
33,200 ppm
332,000 ppm
The random molecular motion of a substance is greatest when the substance is
condensed.
a liquid.
frozen.
a gas.
Which of these is an example of an exothermic chemical process?
evaporation of water
melting ice
photosynthesis of glucose
combustion of gasoline
The boiling point of liquid nitrogen is 77 kelvin. It is observed that ice forms at the opening of a container of liquid nitrogen. The best explanation for this observation is
water at zero degrees Celsius is colder than liquid nitrogen and freezes.
the nitrogen boils and then cools to form a solid at the opening of the container.
water trapped in the liquid nitrogen escapes and freezes.
the water vapor in the air over the opening of the liquid nitrogen freezes out.
The specific heat of copper is about 0.4 joules/gram °C. How much heat is needed to change the temperature of a 30-gram sample of copper from 20.0 °C to 60.0 °C?
1000 J
720 J
480 J
240 J
Equal volumes of 1 molar hydrochloric acid (HCl) and 1 molar sodium hydroxide base (NaOH) are mixed. After mixing, the solution will be
strongly acidic.
weakly acidic.
nearly neutral.
weakly basic.
The above picture shows a light bulb connected to a battery with the circuit interrupted by a solution. When dissolved in the water to form a 1.0 molar solution, all of the following substances will complete a circuit allowing the bulb to light except
hydrochloric acid.
sodium nitrate.
sucrose.
ammonium sulfate.
Which of the following is an observable property of many acids?
They become slippery when reacting with water.
They react with metals to release hydrogen gas.
They produce salts when mixed with other acids.
They become more acidic when mixed with a base.
Copper (II) nitrate and sodium hydroxide solutions react in a test tube as shown below.
If nitric acid is added to the test tube, the amount of solid precipitate decreases. The best explanation for this is that the acid
dilutes the solution making the precipitate dissolve.
reacts with the copper (II) nitrate, pulling the equilibrium to the left.
will dissolve most solids, including sodium nitrate.
will react with the copper (II) hydroxide to form water and soluble copper (II) nitrate.
Potassium hydroxide (KOH) is a strong base because it
easily releases hydroxide ions.
does not dissolve in water.
reacts to form salt crystals in water.
does not conduct an electric current.
Of four different laboratory solutions, the solution with the highest acidity has a pH of
11.
7.
5.
3.
Which of these describes the rate of this chemical reaction?
an increase in the concentration of HCl and H2 with time
an increase in the concentration of HCl with time
an increase in H2 and Cl2 with time
a decrease in HCl and Cl2 with time
Which of the following changes will cause an increase in the rate of the reaction below?
increasing the concentration of Br2
decreasing the concentration of C6H6
increasing the concentration of HBr
decreasing the temperature
If the reaction below takes place inside a sealed reaction chamber, then which of these procedures will cause a decrease in the rate of reaction?
2CO + O2 → 2CO2
raising the temperature of the reaction chamber
increasing the volume inside the reaction chamber
removing the CO2 as it is formed
adding more CO to the reaction chamber
A catalyst can speed up the rate of a given chemical reaction by
increasing the equilibrium constant in favor of products.
lowering the activation energy required for the reaction to occur.
raising the temperature at which the reaction occurs.
increasing the pressure of reactants, thus favoring products.
Which reaction diagram shows the effect of using the appropriate catalyst in a chemical reaction?
H2O2, hydrogen peroxide, naturally breaks down into H2O and O2 over time. MnO2, manganese dioxide, can be used to lower the energy of activation needed for this reaction to take place and, thus, increase the rate of reaction. What type of substance is MnO2?
a catalyst
an enhancer
an inhibitor
a reactant
When a reaction is at equilibrium and more reactant is added, which of the following changes is the immediate result?
The reverse reaction rate remains the same.
The forward reaction rate increases.
The reverse reaction rate decreases.
The forward reaction rate remains the same.
In which of the following reactions involving gases would the forward reaction be favored by an increase in pressure?
A + B ↔ AB
A + B ↔ C + D
2A + B ↔ C + 2D
AC ↔ A + C
Which action will drive the reaction above to the right?
heating the equilibrium mixture
adding water to the system
decreasing the oxygen concentration
increasing the system’s pressure
The reaction shown above occurs inside a closed flask. What action will shift the reaction to the left?
pumping CO gas into the closed flask
raising the total pressure inside the flask
increasing the NO concentration in the flask
venting some CO2 gas from the flask
What kind of change will shift the reaction above to the right to form more products?
a decrease in total pressure
an increase in the concentration of HCl
an increase in the pressure of NH3
a decrease in temperature
In a sealed bottle that is half full of water, equilibrium will be attained when water molecules
cease to evaporate.
begin to condense.
are equal in number for both the liquid and the gas phase.
evaporate and condense at equal rates.
C3H8 + O2 → CO2 + H2O
This chemical equation represents the combustion of propane. When correctly balanced, the coefficient for water is
2.
4.
8.
16.
Which of the following is a balanced equation for the combustion of ethanol (CH3CH2OH)?
CH3CH2OH + 3O2 → CO2 + 2H2O
CH3CH2OH + 3O2 → 2CO2 + 3H2O
CH3CH2OH + O2 → 2CO2 + 2H2O
CH3CH2OH + 2O2 → 3CO2 + 2H2O
Hydrazine, N2H4, and dinitrogen tetroxide, N2O4 react to form gaseous nitrogen and water. Which of these represents a properly balanced equation for this reaction?
N2H4 + N2O4 → N2 + H2O
2N2H4 + N2O4 → 2N2 + 4H2O
2N2H4 + N2O4 → 3N2 + 4H2O
2N2H4 + 3N2O4 → 5N2 + 6H2O
___NH3(g) + ___O2(g) → ___N2(g) + ___H2O(g) When the reaction above is completely balanced, the coefficient for NH3 will be
2
3
4
6
How many moles of carbon-12 are contained in exactly 6 grams of carbon-12?
0.5 mole
2.0 moles
3.01 ×1023 moles
6.02 ×1023 moles
How many atoms are contained in 97.6 g of platinum (Pt)?
5.16 × 1030
3.01 × 1023
1.20 × 1024
1.10 × 1028
When methane (CH4) gas is burned in the presence of oxygen, the following chemical reaction occurs.
CH4 + 2O2 → CO2 + 2H2O
If 1 mole of methane reacts with 2 moles of oxygen, then
6.02 ×1023 molecules of CO2 and 6.02 ×1023 molecules of H2Oare produced.
1.2 ×1024 molecules of CO2 and 1.2 ×1024 molecules of H2Oare produced.
6.02 ×1023 molecules of CO2 and 1.2 ×1024 molecules of H2Oare produced.
1.2 ×1024 molecules of CO2 and 6.02 ×1023 molecules of H2Oare produced.
How many moles of CH4 are contained in 96.0 grams of CH4?
3.00 moles
6.00 moles
12.0 moles
16.0 moles
How many atoms are in a chromium sample with a mass of 13 grams?
1.5 ×1023
3.3 ×1023
1.9 ×1026
2.4 ×1024
How many moles of chlorine gas are contained in 9.03 ×1023 molecules?
1.5 moles
2.0 moles
6.02 moles
9.03 moles
Fe2O3 + 3CO → 2Fe + 3CO2
In this reaction, how many grams of Fe2O3 are required to completely react with 84 grams of CO?
64 g
80 g
160 g
1400 g
Mg3N2(s) + 6H2O(l) → 2NH3(aq) + 3Mg(OH)2(s)
If 54.0 grams of water are mixed with excess magnesium nitride, then how many grams of ammonia are produced?
1.00
17.0
51.0
153
A mass of 5.4 grams of aluminum (Al) reacts with an excess of copper (II) chloride (CuCl2) in solution, as shown below.