Chem-135 Final Review
Write the chemical formula for ammonium phosphide
(NH₄)₃P
What is the oxidation number of each oxygen atom in HOOH?
-1
The oxidation number of a phosphorus atom in P₄ is
0
The oxidation number of chlorine in Cl₂ is
0
The element antimony (Sb) has an atomic mass of 121.76 amu. Two naturally occurring isotopes of antimony are ¹²¹Sb (57% abundant) and ¹²³Sb (43% abundant). In a sample of 100 Sb atoms, what is the probability that a single selected atom has a mass of 121.76 amu? A) 0% B) 43% C) 57% D) 100% E) Not possible to determine.
0% The atomic mass is an average that represents the abundance of each isotope. No individual atom has this mass.
What is the smallest whole-number coefficient for H₂O when the equation MnO₄⁻ + I⁻ + H₂O → MnO₂ + IO₃⁻ is balanced in basic solution?
1 In the equation Mn decreases in oxidation number from +7 to +4, a gain of three electrons, and I increases in oxidation number from -1 to +5, a loss of six electron. Therefore MnO₄⁻ must have a coefficient of 2. That gives a -3 charge on the left and a -1 charge on the right, so the charge can be balanced by adding 2 OH⁻ ions on the right. We then note that the O and H atoms are balanced.
How many carbon atoms are in 19 molecules of benzene, C₆H₆?
114
Fill in the blank: A mole is defined as the number of carbon atoms in __________ g of pure ¹²C.
12 A mole is defined as the number of carbon atoms in 12 g of pure 12C12C.
How many oxygen atoms are in 17 molecules of sucrose, C₁₂H₂₂O₁₁ ?
187
When an electron in excited energy level drops to a lower energy level, a photon is emitted. If the electron is dropping to n=1, which transition will emit the longest wavelength? n=______ to n=1.
2
Write the balanced NET ionic equation for the reaction when aqueous calcium chloride and aqueous lead(II) nitrate are mixed in solution to form aqueous calcium nitrate and solid lead(II) chloride.
2 Cl⁻(aq) + Pb²⁺(aq) → PbCl₂(s)
The oxidation number of the chlorine atom in ClF₃ is
3
What is the coefficient in front of the O₂ when the equation below is balanced (using only whole numbers and the lowest whole number ratio)? C₂H₄(g) + O₂ (g) → CO₂(g) + H₂O (g)
3
In one atom, what is the maximum number of electrons that could have the quantum number of n = 4?
32 electrons When n=4, there are one 4s orbital, three 4p orbitals, five 4d orbitals, and seven 4f orbitals. There can be two electrons in each orbital. Thus, 2×16orbitals=32electrons
What is the oxidation number of S in the compound Na₂S₂O₅?
4
The oxidation number of the sulfur atom in SF₄ is
4 Fluorine has an oxidation number of -1 when not in its elemental state. Multiply the number of fluorine by its oxidation number. Add the oxidation numbers of all atoms together and set equal to the charge on the molecule, which is zero. The oxidation number of sulfur can then be calculated.
The oxidation number of the chlorine atom in ClO₂ is
4 Oxygen has an oxidation number of -2 when not in its elemental state. Multiply the number of oxygen by its oxidation number. Add the oxidation numbers of all atoms together and set equal to the charge on the molecule, which is zero. The oxidation number of chlorine can then be calculated.
How many significant figures does the number 23.070 have?
5
Which of the following contains the most moles of atoms? A) 1 g of helium B) 1 g of carbon C) 1 g of uranium D) All contain equal number of atoms E) Not enough information
A) 1 g of helium To convert from grams to moles, you need to divide by the molar mass. Since each of these options has the same mass, dividing by the smallest molar mass will yield the most moles of atoms. Since helium has a lower molar mass (4 g/mol) than carbon (12 g/mol) or uranium (238 g/mol), it must contain the most moles.
Which of the following temperatures is the coldest? A) 100 K B) 100 °C C) 100 °F
A) 100 K Temperature in Kelvin (K) is the lowest because it is the absolute temperature. Given the same numerical value, Kelvin would always be the lowest temperature.
How would you determine the formula weight of NaCl? A) Add the mass of sodium (22.99 amu) plus the mass of chlorine together (35.45 amu). B) Multiply the mass of sodium (22.99 amu) by the mass of chlorine (35.45 amu). C) Divide the mass of chlorine (35.45 amu) by the mass by sodium (22.99 amu). D) Subtract the mass of chlorine (35.45 amu) from the mass of sodium (22.99 amu).
A) Add the mass of sodium (22.99 amu) plus the mass of chlorine together (35.45 amu).
Balance the following chemical reaction: Al₂(SO₄)₃ (aq) + K₃PO₄ (aq) → AlPO₄ (s) + K₂SO₄ (aq) A) Al₂(SO₄)₃ (aq) + 2 K₃PO₄ (aq) → 2 AlPO₄ (s) + 3 K₂SO₄ (aq) B) 2 Al₂(SO₄)₃ (aq) + 6 K₃PO₄ (aq) → 3 AlPO₄ (s) + 6 K₂SO₄ (aq) C) 2 Al₂(SO₄)₃ (aq) + 4 K₃PO₄ (aq) → 4 AlPO₄ (s) + 6 K₂SO₄ (aq) D) AlSO₄ (aq) + KPO₄ (aq) → AlPO₄ (s) + KSO₄ (aq)
A) Al₂(SO₄)₃ (aq) + 2 K₃PO₄ (aq) → 2 AlPO₄ (s) + 3 K₂SO₄ (aq)
What is the formula of a compound containing Al³⁺ and S²⁻ ions? A) Al₂S₃ B) Al₂S C) AlS₃ D) Al₃S₂
A) Al₂S₃
Which of the following series of isoelectronic ions correctly lists the ions in order of increasing size (i.e., smallest to largest)? A) Ca²⁺ < K⁺ < Cl⁻ < P³⁻ B) K⁺ < Ca²⁺ < P³⁻ < Cl⁻ C) P³⁻ < Cl⁻ < K⁺ < Ca²⁺ D) Cl⁻ < K⁺ < Ca²⁺ < P³⁻ E) K⁺ < Ca²⁺ < Cl⁻ < P³⁻
A) Ca²⁺ < K⁺ < Cl⁻ < P³⁻ For isoelectronic species, anions will be larger than cations. Ions can be further ranked by considering their charges. The greater the negative charge, the larger the size. The greater the positive charge, the smaller the size.
Classify the following compounds as ionic or covalent: OF₂, CuO, SeO₂. A) Covalent, ionic, covalent. B) Ionic, covalent, ionic. C) Covalent, covalent, ionic. D) Ionic, ionic, covalent.
A) Covalent, ionic, covalent.
The accepted value for the density of iron is 7.9 g/mL. Which of the following sets of experimental data for the density of iron is the most accurate? A) Group 1: 7.98 g/mL, 7.85 g/mL B) Group 2: 7.65 g/mL, 7.64 g/mL C) Group 3: 7.03 g/mL, 8.54 g/mL D) Group 4: 5.43 g/mL, 5.47 g/mL
A) Group 1: 7.98 g/mL, 7.85 g/mL
Which of the following aqueous solutions would NOT form a precipitate when added to a solution of silver nitrate? A) NaF B) NaCl C) NaBr D) NaI
A) NaF Silver halides are insoluble, except silver fluoride.
Which of the following elements would have a very different electron affinity value compared to the others? A) Ne B) Al C) O D) F E) Na
A) Ne The electron affinity is the change in energy when an electron is added to a neutral gaseous atom to form an ion. It would require a lot of energy to do this for neon because it is a noble gas with a full octet.
List the following atoms in order of increasing size (atomic radius): Pb, Rn, Ba. A) Rn < Pb < Ba B) Rn < Ba < Pb C) Ba < Pb < Rn D) Pb < Rn < Ba
A) Rn < Pb < Ba Rn < Pb < Ba. In general, atomic radius decreases across a period and increases down a group.
If you were given the task of measuring 75 milliliters of a liquid, which measuring device would you use? A) a 100-milliliter graduated cylinder B) a 25-milliliter pipette C) a 50-milliliter buret D) a 250-milliliter volumetric flask
A) a 100-milliliter graduated cylinder A graduated cylinder has markings to allow for a meniscus reading at volumes that are less than the total volume. A volumetric flask only contains one marking and cannot be used to measure amounts smaller than that. It is best to use a measurement tool that does not require splitting the sample to measure it.
What type of reaction is represented by the following equation: KOH(aq) + NH₄Cl(aq) → NH₃(aq) + KCl(aq) + H₂O(l) A) acid-base B) decomposition C) precipitation D) redox (oxidation-reduction)
A) acid-base This is an acid-base reaction, which involves the transfer of a proton from one species (the acid, in this case NH₄⁺) to another (the base, in this case OH⁻).
Equal amounts of heat are added to equal masses of substances A and B at the same temperature, but substance B gets hotter. What is true of their heat capacities (c)? A) c(A) > c(B) B) c(B) > c(A) C) c(a) = c(B) D) Not enough info
A) c(A) > c(B) The heat capacity is the heat needed to raise the temperature. If substance B gets hotter, this indicates that the heat capacity for substance A is higher.
Which of the following devices is used to directly measure reaction enthalpy change at constant pressure? A) coffee-cup calorimeter B) bomb calorimeter C) hygrometer D) viscometer E) barometer
A) coffee-cup calorimeter Because it is not sealed, a coffee cup calorimeter operates at the constant atmospheric pressure of the lab space, and therefore provides a direct measurement of reaction enthalpy change.
If ℓ = 0, which of the following may be true? A) n = 6 B) mℓ = -1 C) mℓ = 1 D) ms = 1 E) ms = 0
A) n = 6
The reason an ionic bond forms can best be described as A) the energy change for electron transfer results in a large gain in stability when the ionic bond forms. B) two atoms need to share electrons in order to fill their valence shells. C) two atoms exist as ions and the ions are attracted to each other. D) the atoms that form cations have low ionization energy and anions have high electron affinity, so the two atoms exchange electrons.
A) the energy change for electron transfer results in a large gain in stability when the ionic bond forms.
You measured the mass of a dry powder on a balance to be 23.76 g. What would you report as the uncertainty of this measurement? A) ± 0.01 B) ± 0.1 C) ± 1 D) ± 0.001
A) ± 0.01
Write the chemical formula for aluminum hypochlorite octahydrate
Al(ClO)₃•8H₂O
Write the empirical formula corresponding to Al₂Br₆
AlBr₃
Write the chemical formula for aluminum chloride hexahydrate
AlCl₃•6H₂O
In which direction on the periodic table does metallic character increase? A) Down and to the right. B) Down and to the left. C) As you move toward the middle of the table. D) Up and to the right. E) Up and to the left.
B) Down and to the left.
Einstein's work on the photoelectric effect validated and made extensive use of which of the following equations? A) Ek = 1/2mv² B) E = hν C) E = mc² D) λ = h/mν E) ν = c/λ
B) E = hν
The energy released in the reaction F(g) + e⁻ → F⁻(g) is known as the A) Ionization energy B) Electron affinity C) Enthalpy of ionization D) Electronegativity E) Enthalpy of electronegativity
B) Electron affinity The electron affinity is the change in energy when an electron is added to a neutral gaseous atom to form an ion.
The accepted value for the density of iron is 7.9 g/mL. Which of the following sets of experimental data for the density of iron is the most precise? A) Group 1: 7.98 g/mL, 7.85 g/mL B) Group 2: 7.65 g/mL, 7.64 g/mL C) Group 3: 7.03 g/mL, 8.54 g/mL D) Group 4: 5.43 g/mL, 5.47 g/mL
B) Group 2: 7.65 g/mL, 7.64 g/mL
Which scientist surmised the scientific principle that the position and momentum of an electron cannot be known simultaneously with a high degree of accuracy? A) Planck B) Heisenberg C) Schrödinger D) de Broglie E) Pauli
B) Heisenberg Heisenberg was the scientist who determined that certain pairs of qualities, such as position and momentum, cannot be known simultaneously. This postulate is called the uncertainty principle, or Heisenberg's uncertainty principle.
What is the oxidizing agent in the reaction Zn + 2 H⁺ → Zn²⁺ + H₂? A) Zn B) H⁺ C) Zn²⁺ D) H₂ E) This is not a redox reaction.
B) H⁺ An oxidizing agent must be a reactant. Zn increases in oxidation number from 0 to +2 and H⁺ decreases in oxidation number from +1 to 0. Therefore Zn is being oxidized, and H⁺ is the oxidizing agent.
Consider these electron transitions in a hydrogen atom: I. n = 2 → n = 1 II. n = 3 → n = 1 III. n= 1 → n = 4 Which of the electron transitions would release the most energy? A) I B) II C) III D) I, II, and III release the same amount of energy
B) II Electron transitions from higher to lower energy states represent an emission of energy. The greater the separation of energy states, the greater the amount of energy released upon transition to the lower energy state.
Which has the incorrect name-formula combination? A) Cobalt(II) chlorite - Co(ClO₂)₂ B) Iron(II) chlorate - FeClO₄ C) Manganese(II) perchlorate - Mn(ClO₄)₂ D) Chromium(III) hypochlorite - Cr(ClO)₃
B) Iron(II) chlorate - FeClO₄ Consider the charge of the ions to make sure the charges are balanced. For the transition metals, the charge is indicated in the name with a Roman numeral in parentheses. For example iron(II) chlorate, indicates that the iron ion has a +2 charge. Chlorate is a polyatomic ion with a -1 charge, ClO₃⁻. Two chlorate ions would be needed to balance one iron ion, yield a formula of Fe(ClO₃)₂ for iron(II) chlorate.
The law of conservation of mass is best described as which of the following statements? A) The total energy of the universe is constant. B) Matter can neither be created nor destroyed. C) Energy equals mass times the speed of light squared. D) For every action, there is an equal and opposite reaction. E) Mass can only decrease as a result of a chemical reaction.
B) Matter can neither be created nor destroyed. The law of conservation of mass states that matter can neither be created nor destroyed. As a result, the mass of the products of a chemical reaction must equal the mass of the reactants.
The precipitate formed when Ni(NO₃)₂ is mixed with Li₂S is A) Ni₂S B) NiS C) LiNO₃ D) Li₂NO₃
B) NiS The products of this reaction are nickel(II) sulfide and lithium nitrate. Lithium nitrate is soluble in water. Nickel(II) sulfide is insoluble in water and its chemical formula is NiS.
Which of the following is best classified as a covalent compound? A) Sr₃N₂ B) N₂O₅ C) Li₃N D) AlN
B) N₂O₅
Which electrode will gain mass while a voltaic cell runs and why? (Choose the best answer.) A) The cathode because it undergoes reduction, which means electrons are gained which add mass. B) The cathode because it undergoes reduction, which means that the metallic ions plate onto the cathode. C) The anode because it undergoes reduction, which means that the metallic ions plate onto the anode. D) The anode because it undergoes oxidation, which means that it will lose electrons. E) Neither electrode will gain mass because electrons are lost at the same rate as metallic ions are plated.
B) The cathode because it undergoes reduction, which means that the metallic ions plate onto the cathode. As the voltaic cell operates, the cathode will undergo reduction. In the reaction metallic ions from the solution will become metal atoms and plate onto the electrode, thus increasing the mass of this electrode.
A bomb calorimeter cannot measure the enthalpy of a reaction directly because it operates at constant: A) Pressure B) Volume C) Temperature D) Electrical current E) Heat
B) Volume A bomb calorimeter operates at constant volume within a sealed bomb immersed in water, which is monitored for changes in temperature. Because enthalpy is defined at constant pressure, it cannot be directly measured using a bomb calorimeter.
Positively charged particles of radiation emitted from the decay of radioactive substances are known as A) protons B) alpha particles C) beta particles D) electrons E) gamma rays
B) alpha particles
Which of the following has four valence electrons? A) beryllium B) carbon C) sodium D) sulfur
B) carbon
Classify the following reaction: 2KClO₃(s) → 3O₂(g) + 2KCl(s) A) synthesis B) decomposition C) combustion D) single displacement (replacement) E) double displacement (replacement)
B) decomposition
Classify the following reaction: NH₂NO₂(aq) → N₂O(g) + H₂O(l) A) synthesis B) decomposition C) combustion D) single displacement (replacement) E) double displacement (replacement)
B) decomposition
In the process of making biofuel from corn, the corn is ground, mixed with water, and then enzymes are added to hydrolyze the starch into smaller sugar molecules. The fermentation produces ethanol and carbon dioxide. In a subsequent step, a microorganism ferments the sugars into ethanol and carbon dioxide. The ethanol is further distilled for use as a biofuel. In this process ______ is an example of a chemical change. A) grinding the corn B) fermenting the starch C) distilling the ethanol D) mixing the corn with water
B) fermenting the starch Fermentation is an example of a chemical change where starch and sugars are converted into ethanol by enzymes.
In the Bohr model of the hydrogen atom, the energy required to excite an electron from n = 2 to n = 3 is _______________ the energy required to excite an electron from n = 3 to n = 4? A) less than B) greater than C) equal to D) equal to or less than E) equal to or greater than
B) greater than The Bohr model of the atom states that the energy required to transition between two energy levels is equal to the difference between the inverse squares of the energy levels multiplied by a constant.
Which type of error has an equal probability of a measurement being high or low? A) systematic B) random C) determinate D) uncertainty
B) random A random error can be an error in either direction (high or low) from the measurement.
Which of the following sets of elements and symbols is paired incorrectly? A) iron, Fe B) sodium, S C) tin, Sn D) potassium, K E) copper, Cu
B) sodium, S
In an investigation of the electronic absorption spectrum of a particular element, it is found that a photon having λ = 500 nm provides just enough energy to promote an electron from n = 2 to n = 3. From this information, we can deduce A) the energy of the n = 3 level. B) the difference between the energies of the n = 2 and n = 3 levels. C) the energy of the n = 2 level. D) the sum of the energies of the n = 2 and n = 3 levels. E) all of these.
B) the difference between the energies of the n = 2 and n = 3 levels.
Which of the following best categorizes the idea that the rate of a reaction is dependent on temperature because the rate ultimately depends on the frequency of collisions between reacting species (atoms, molecules, etc.)? A) scientific law B) theory C) hypothesis D) observation
B) theory
Which element is classified as a transition metal? A) lithium (Li) B) zirconium (Zr) C) tellurium (Te) D) xenon (Xe)
B) zirconium (Zr)
Cl₂ is a stable diatomic molecule. It can be decomposed to form two Cl atoms as shown below. Cl₂ → 2Cl(g) Predict the change in enthalpy (∆H) of this reaction. A) ∆H is (-); endothermic B) ∆H is (+); endothermic C) ∆H is (-); exothermic D) ∆H is (+); exothermic E) ∆H = 0; thermoneutral
B) ∆H is (+); endothermic ∆H is (+); endothermic. Cl₂ is a stable molecule so bond-breaking will be endothermic requiring an input of heat. Bond-breaking is always endothermic.
Write the empirical formula corresponding to B₃N₃H₆
BNH₂
Write the chemical formula for the hypobromite ion
BrO⁻
Write the chemical formula for the bromate ion
BrO₃⁻
Predict the chemical formula for the ionic compound formed by the elements B and O.
B₂O₃
Which of the following numbers contains three significant figures? A) 0.23 B) 0.023 C) 0.00230 D) 2.300 E) 0.2303
C) 0.00230 Count the number of significant figures in each option. Be sure to account for non-zero digits, zeros found between two significant digits, and zeros following a significant digit in a decimal. Leading zeros and trailing zeros without a decimal point are not significant. The value 0.00230, contains three significant figures.
If you have 1 mol Xe and 1 mol F₂, how many moles of XeF₄ can you create in the following chemical reaction? Xe (g) + 2 F₂ (g) → XeF₄ (g) A) 2 mol B) 1 mol C) 0.5 mol D) 0.25 mol
C) 0.5 mol Calculate the amount of XeF₄ that could be made from the given amount of each reactant, if it were not limiting. 1molXeF₄ 0.5molXeF₄ Therefore F₂ is the limiting reactant, and 0.5 mol of XeF₄ will be produced.
The chemical formula of caffeine is C₈H₁₀N₄O₂. How many N atoms are in 4 molecules of caffeine? A) 4 B) 8 C) 16 D) 32 E) 2
C) 16
How many core electrons does an atom of beryllium (Be) contain? A) 0 B) 1 C) 2 D) 3 E) 4
C) 2 Be has four electrons and an electron configuration of 1s²2s². The electrons in the 1st shell are in the core and the electrons in the outer shell are valence electrons.
For which atomic orbital does n = 3 and ℓ = 1? A) 2s B) 3s C) 3p D) 3d E) 4d
C) 3p
Which of the orbital electron configurations is not possible? A) 2s¹ B) 3d¹⁰ C) 4p⁷ D) 4f⁷ E) 2p⁶
C) 4p⁷
How many significant figures does the number 48.050 have? A) 3 B) 4 C) 5 D) 2
C) 5
There are two naturally occurring isotopes of europium, ¹⁵¹Eu (151.0 amu) and ¹⁵³Eu (153.0 amu). If the atomic mass of Eu is 151.96, what is the approximate natural abundance of ¹⁵¹Eu? A) 20% B) 40% C) 50% D) 60% E) 80%
C) 50% The atomic mass is an average that represents the abundance of each isotope. The average number of these two isotopes is 152.0 amu if they are equally abundant.
Which of the following is an example of an empirical formula? A) C₂O₂H₂ B) C₄H₈ C) C₇H₁₄Cl₂ D) C₆H₉O₃ E) C₈H₁₀
C) C₇H₁₄Cl₂
If a hydrogen (H) atom and a helium (He) atom travel at the same speed, which of the following is true about the de Broglie wavelengths of the atoms? A) The H atom is about 2 times longer than the He atom. B) The H atom is approximately the same as the He atom. C) The H atom is about 4 times longer than the He atom. D) The He atom is about 2 times longer than the H atom. E) The He atom is about 4 times longer than the H atom.
C) The H atom is about 4 times longer than the He atom.
Which of the following is best classified as an ionic compound? A) S₄N₄ B) SO₃ C) ZnS D) S₂F₁₀
C) ZnS
Which of the following metric prefixes corresponds to 10⁶? A) centi- B) kilo- C) mega- D) micro- E) milli-
C) mega-
Which one of the following is an example of a heterogeneous mixture? A) coffee B) water C) sand D) tap water
C) sand If a sample of matter is a mixture that is not uniform in composition, it's a heterogeneous mixture. Sand does not have a uniform composition.
The uncertainty in the measurement 13.560 mg is A) ± 0.1 mg B) ± 0.01 mg C) ± 0.001 mg D) ± 0.0001 mg
C) ± 0.001 mg
Write the chemical formula for calcium hydride
CaH₂
Write the chemical formula for cadmium nitrate tetrahydrate
Cd(NO₃)₂•4H₂O
Write the chemical formula for the chlorite ion
ClO₂⁻
Write the chemical formula for the chlorate ion
ClO₃⁻
What are the coefficients in front of the H₂ and the Au if you balance the following unbalanced equation: Au₂S₃ + H₂ → Au + H₂S? A) 3, 6 B) 6, 4 C) 6, 2 D) 3, 2
D) 3, 2 Matter is conserved in a chemical reaction. Balanced equations contain the same number of atoms of each element on each side of the equation. A coefficient of 3 in front of H₂, a coefficient of 2 in front of Au and a coefficient of 3 in front of H₂S yield the same number of Au, H, and S atoms.
Which of the following orbitals cannot exist? A) 2p B) 3d C) 4d D) 3f E) 162p
D) 3f
In a multi-electron atom, which orbital will have the highest energy? A) 4s B) 4p C) 4d D) 4f E) All are equal
D) 4f
Which of the following is a state function? A) Pressure B) Volume C) Temperature D) All of the above
D) All of the above State functions are properties that have values that are pathway independent.
Which of the following is a covalent compound? A) O₂ B) MgCO₃ C) LiNO₃ D) NO₂
D) NO₂ Covalent compounds are usually formed between two or more nonmetal atoms. The atoms form bonds by sharing electrons. NO₂ is a covalent compound.
A compound containing Na, C, and O is found to have 1.06 mol Na, 0.528 mol C, and 1.59 mol O. What is the empirical formula of the compound? A) NaCO B) Na₂CO C) Na₂CO₂ D) Na₂CO₃
D) Na₂CO₃ An empirical formula shows the ratio of each element to one another in the formula unit or molecule. The given moles show that there are twice as many moles of Na as moles of C and that there are three times as many moles of O as moles of C. This yields Na₂CO₃.
Which choice correctly identifies the oxidation number (O.N.) for the given species? A) Mn²⁺, O.N. = 0 B) Ca, O.N. = +2 C) F₂, O.N. = -1 D) Se²⁻, O.N. -2 E) P₄, O.N. = -1
D) Se²⁻, O.N. -2
The best reason for why a covalent bond forms is A) two atoms exist as ions and the ions are attracted to each other. B) the atoms that form cations have low ionization energy and anions have high electron affinity, so the two atoms exchange electrons. C) nonmetal atoms cannot react with each other unless they share electrons. D) atoms with high electronegativities will not lose electrons, so instead they share electrons to reach a stable number of valence electrons.
D) atoms with high electronegativities will not lose electrons, so instead they share electrons to reach a stable number of valence electrons.
What type of reaction is represented by the following equation: SiCl₄(l) + 2Mg(s) → 2MgCl₂(s) + Si(s) A) combination B) decomposition C) double displacement D) single displacement
D) single displacement
Classify the following reaction: H₂SO₄(aq) + Fe(s) → H₂(g) + FeSO₄(aq) A) synthesis B) decomposition C) combustion D) single displacement (replacement) E) double displacement (replacement)
D) single displacement (replacement)
Which color (frequency) of light travels the fastest in a vacuum? A) Red B) Yellow C) Green D) Violet E) All have the same speed
E) All have the same speed
For the electrochemical cell represented by Cr²⁺ | Cr³⁺ || Li⁺ | Li, E°(cell) = -2.63 V. This cell: A) Runs spontaneously B) Does not run spontaneously C) Is galvanic D) Is electrolytic E) Both (B) and (D)
E) Both (B) and (D) An electrochemical cell with a negative voltage is not spontaneous, so it occurs only if electrical energy is applied. Therefore both does not run spontaneously and is electrolytic is correct.
Consider the following reaction: Mg²⁺(aq) + Cu(s) → Cu²⁺(aq) + Mg(s). In this reaction, Mg²⁺(aq) is: A) Oxidized B) Reduced C) A reducing agent D) An oxidizing agent E) Both (B) and (D)
E) Both (B) and (D) Oxidizing agents gain electrons and are reduced. Reducing agents lose electrons and are oxidized. In this reaction, Mg²⁺ gains two electrons when it becomes Mg.
Which of the following species contains manganese with the highest oxidation number? A) Mn B) MnF₂ C) Mn₃(PO₄)₂ D) MnCl₄ E) NaMnO₄
E) NaMnO₄
Conduction, convection, and radiation are all ways of transferring _____ energy. A) work B) potential C) gravitational D) chemical E) thermal
E) thermal Conduction, convection, and radiation are all ways thermal energy is transferred. Thermal energy is transferred primarily through solids by conduction, through fluids by convection, and through any medium by radiation.
What does the mass number of an atom represent? A) number of neutrons in the atom B) number of protons in the atom C) atomic mass of the element D) total number of electrons and neutrons in the atom E) total number of protons and neutrons in the atom
E) total number of protons and neutrons in the atom
Write the chemical formula for hydrocyanic acid
HCN
Write the chemical formula for the bicarbonate ion
HCO₃⁻
Write the chemical formula for dinitrogen monoxide
N₂O
Write the chemical formula for the azide ion
N₃⁻
Write the chemical formula for the cyanate ion
OCN⁻
Write the chemical formula for tetraphosphorus hexasulfide
P₄S₆
The uncertainty in the measurement 97.00 mL is A) ± 1 mL B) ± 0.1 mL C) ± 0.01 mL D) ± 0.001 mL
The last significant digit of a measurement is uncertain and its place value is used in the uncertainty. For example, the 0 in the hundredths place in 97.00 is uncertain, yielding an uncertainty measurement of ± 0.01.
Atoms from which of the following pairs are most likely to form an ionic bond? A) sodium and potassium B) titanium and oxygen C) sodium and barium D) nitrogen and fluorine
Titanium and oxygen atoms are expected to form ionic bonds. Metallic atoms and nonmetallic atoms usually form ionic bonds when they join due to the relatively large difference in their electronegativity.
What is the correct IUPAC name for Al(HSO₄)₃?
aluminum hydrogen sulfate
What is the correct IUPAC name for AlN?
aluminum nitride
What is the correct IUPAC name for BaCr₂O₇?
barium dichromate
What is the correct IUPAC name for BaHPO₄?
barium hydrogen phosphate
What is the correct IUPAC name for Ca(BrO₂)₂?
calcium bromite
What is the correct IUPAC name for Ca(IO₂)₂?
calcium iodite
What is the correct IUPAC name for CBr₄?
carbon tetrabromide
What is the correct IUPAC name for CsI?
cesium iodide
What is the correct IUPAC name for CuMnO₄?
copper(I) permanganate
What is the correct IUPAC name for Cu₂S?
copper(I) sulfide
What is the correct IUPAC name for As₂S₅?
diarsenic pentasulfide
What is the correct IUPAC name for N₂O₄?
dinitrogen tetroxide
What is the correct IUPAC name for S₂F₈?
disulfur octafluoride
What is the correct IUPAC name for Au₂(CrO₄)₃?
gold(III) chromate
What is the correct IUPAC name for HCN(aq)?
hydrocyanic acid
What is the correct IUPAC name for HBrO(aq)?
hypobromous acid
What is the correct IUPAC name for HOF(aq)?
hypofluorous acid
What is the correct IUPAC name for IF₅?
iodine pentafluoride
What is the correct IUPAC name for HNO₂(aq)?
nitrous acid
What is the correct IUPAC name for HClO₄(aq)?
perchloric acid
What is the correct IUPAC name for K₂S₂O₃?
potassium thiosulfate
What is the correct IUPAC name for Sr(OH)₂ ·7H₂O?
strontium hydroxide heptahydrate
What is the correct IUPAC name for Sn(HPO₄)₂?
tin(IV) hydrogen phosphate
What is the concentration of sodium ions in 0.300 M Na₂SO₄?
0.600 M
The oxidation number of a nitrogen atom in N₂O₃ is
3 Oxygen has an oxidation number of -2 when not in its elemental state. Multiply the number of oxygen by its oxidation number. Add the oxidation numbers of all atoms together and set equal to the charge on the molecule, which is zero. The oxidation number of nitrogen can then be calculated.
Which one of the following is the least electronegative atom? A) Na B) Cl C) P D) Al
A) Na Alkali metals and alkaline earth metals have lower electronegativities.
Identify which of the following molecules has a double bond. A) O₂ B) H₂ C) Br₂ D) HF
A) O₂ Main group elements obey the octet rule. The Lewis structure for O₂ has a double bond with 4 valence electrons around each oxygen atom.
Write the balanced NET ionic equation for the reaction when Al(NO₃)₃ and NaOH are mixed in aqueous solution. If no reaction occurs, simply write only NR.
Al³⁺(aq) + 3 OH⁻(aq) → Al(OH)₃(s)
Predict the chemical formula for the ionic compound formed by Au³⁺ and HSO₃⁻
Au(HSO₃)₃
How many neutrons are in an atom of uranium-235? A) 92 B) 143 C) 235 D) 238.0
B) 143
Write the chemical formula for barium nitride
Ba₃N₂
Determine the correct formula for chromium(II) nitrite. A) CrNO₂ B) Cr₂NO₂ C) Cr(NO₂)₂ D) Cr₃(NO₂)₂
C) Cr(NO₂)₂ The (II) in chromium(II) nitrite indicates that the chromium ion has a 2+ charge. Nitrite is a polyatomic ion that has a -1 charge. Two nitrite ions would be needed to balance the charge on the chromium ion.
Carbon dioxide is a _____ compound composed two types of _____ atoms. A) molecular; metal B) ionic; metalloid C) molecular; nonmetal D) ionic; metal
C) molecular; nonmetal
Rutherford's gold foil experiment determined that A) neutrons are in the nucleus. B) electrons have a negative charge. C) most of the space in an atom is empty except for a concentrated area called the nucleus. D) protons and neutrons have about the same mass. E) neutrons have no charge.
C) most of the space in an atom is empty except for a concentrated area called the nucleus.
What is the maximum number of electrons that can have the following set of quantum numbers? n = 4, ℓ = 3, mℓ = 3, ms = -½
1
What is the atomic number for an element whose mass number is 152, which contains 89 neutrons per atom?
63
Write the chemical formula for diarsenic trioxide
As₂O₃
What type of forces hold the atoms together in a sample of silver (Ag) metal? A) covalent bonds B) ionic bonds C) metallic bonds D) dipole-dipole interactions E) dispersion forces
C) metallic bonds
What type of reaction is represented by the following equation: CoCl₂(aq) + 2NaOH(aq) → Co(OH)₂(s) + 2NaCl(aq) A) acid-base B) decomposition C) precipitation D) redox (oxidation-reduction)
C) precipitation This is a precipitation reaction,which involves the formation of an insoluble solid and an aqueous solution.
Which group in the periodic table tends to have high electronegativity values? A) the alkali metals B) the noble gases C) the halogens D) the transition metals
C) the halogens
Write the chemical formula for copper(I) sulfite trihydrate
CuSO₃•3H₂O
Which of the following contains the highest number of atoms? A) 1 mole of helium B) 1 mole of carbon C) 1 mole of uranium D) All contain an equal number of atoms E) Not enough info
D) All contain an equal number of atoms One mole of any substance is equal to 6.022×10^23 particles of that substance.
Which of the following is the first step in the scientific method? A) Hypothesis Formation B) Analysis of Results C) Background Research D) Observation E) Experimentation
D) Observation An observation of a natural phenomenon is the first step in the scientific method. The observation leads to a research question and formulation of a hypothesis, followed by experimentation, and subsequent analysis of results and re-iteration.
Classify the following reaction: 2NaOH(aq) + CuSO₄(aq) → Cu(OH)₂(s) + Na₂SO₄(aq) A) synthesis B) decomposition C) combustion D) single displacement (replacement) E) double displacement (replacement)
E) double displacement (replacement)
Write the chemical formula for the hydrogen carbonate ion
HCO₃⁻
Write the chemical formula for chlorous acid
HClO₂
Write the chemical formula for the hydrogen phosphate ion
HPO₄²⁻
Write the chemical formula for the hydrogen sulfite ion
HSO₃⁻
Write the formula for hydrosulfuric acid
H₂S
Write the chemical formula for the periodate ion
IO₄⁻
What is the correct IUPAC name for Cr₂(SO₄)₃?
chromium(III) sulfate
What is the correct IUPAC name for CoCl₂ ?
cobalt(II) chloride
What is the correct IUPAC name for Co(ClO)₂?
cobalt(II) hypochlorite
What is the correct IUPAC name for Co(BrO)₃?
cobalt(III) hypobromite
What is the correct IUPAC name for Co(NO₃)₃ · 6H₂O?
cobalt(III) nitrate hexahydrate
What is the correct IUPAC name for Fe(HSO₄)₃?
iron(III) hydrogen sulfate
What is the correct IUPAC name for FePO₄ · 4H₂O?
iron(III) phosphate tetrahydrate
What is the correct IUPAC name for Mg₃(PO₄)₂?
magnesium phosphate
What is the correct IUPAC name for Mn(BrO₃)₃?
manganese(III) bromate
What is the correct IUPAC name for MnF₃?
manganese(III) fluoride
How many electrons in an atom can have the following quantum numbers? n = 4, ℓ = 2, mℓ = -2, ms = +½
1
Write the balanced NET ionic equation for the reaction when aqueous (NH₄)₃PO₄ and aqueous Zn(NO₃)₂ are mixed in solution to form solid Zn₃(PO₄)₂ and aqueous NH₄NO₃.
2 PO₄³⁻(aq) + 3 Zn²⁺(aq) → Zn₃(PO₄)₂(s)
A theory is another word for a(n) _________. A) model B) law C) measurement D) experiment
A) model A theory or model is a well established explanation of a phenomenon based on a series of facts and a body of evidence.
How many electrons are in a neutral ⁴¹Ca atom? A) 2 B) 20 C) 21 D) 41
B) 20
In the following chemical reaction, which element is the oxidizing agent? CH₄(g) + 2 O₂(g) → CO₂(g) + 2H₂O(g) A) C B) H C) O D) There is no oxidizing agent in this reaction
C) O Oxidizing agents gain electrons and are reduced. In this reaction, O gains two electrons to become O²⁻.
A heat of formation is A) The heat produced in a reaction when 1 mole of a compound is produced. B) The heat absorbed in a reaction when 1 mole of reactants react. C) The heat required to make 1 mole of a compound from its elements in their standard states. D) The heat absorbed or produced in a combination reaction.
C) The heat required to make 1 mole of a compound from its elements in their standard states.
Based on their positions in the periodic table, which of the following bonds is the most polar? A) C - O B) C - N C) C - B D) C - F
D) C - F Polar bonds occur between two nonmetals and have a difference in electronegativities of the atoms. The further apart two atoms are in the same period, the greater the polarity of the bond.
The relative mass of propylene (C₃H₆) is 42.1 g/mol. How many carbon atoms does a polypropylene molecule with a molar mass of 42.1 kg/mol contain? A) 30,000 B) 300 C) 30 D) 6,000 E) 3,000
E) 3,000 Consider that the prefix prop- corresponds to a three-carbon chain; the ratio of the polymer molar mass to the monomer molar mass is 1,000. Therefore, there are 3,000 carbon atoms in the polypropylene molecule.
Which of the following phosphate salts are insoluble in water? A) (NH₄)₃PO₄ B) Li₃PO₄ C) Na₃PO₄ D) K₃PO₄ E) Ca₃(PO₄)₂
E) Ca₃(PO₄)₂ Ca₃(PO₄)₂ is insoluble in water. Most phosphates are insoluble. Notable exceptions are group 1 metals like lithium, potassium, and sodium, as well as ammonium phosphate which are soluble.
Which of the following is an intensive physical property of a lump of coal? A) Width B) Flammability C) Chemical potential energy D) Mass E) Color
E) Color The color of the coal can be observed through physical means (the naked eye), and does not depend on the amount of coal present.
What is the coefficient in front of the NO when the equation below is balanced? NH₃(g) + O₂ (g) → NO(g) + H₂O (g)
4 Matter is conserved in a chemical reaction. Balanced equations contain the same number of atoms of each element on each side of the equation. The balanced equation for this reaction is: 4 NH₃(g) + 5 O₂ (g) → 4 NO(g) + 6 H₂O (g).
In which of the following species does sulfur have the lowest oxidation number? A) S²⁻ B) S₈ C) SO₃²⁻ D) SO₄²⁻ E) S₂O₃²⁻
A) S²⁻ The oxidation number of an ion is the charge on the ion. S²⁻ has an oxidation number of -2. S₈ has an oxidation number of 0, and a positive oxidation number in the other species, so S²⁻ has the lowest oxidation number.
Write the chemical formula for bromine pentachloride
BrCl₅
Electrons always flow in a voltaic (galvanic) cell from _____ A) the salt bridge to the anode B) the oxidizing agent through the salt bridge to the reducing agent C) the reducing agent through the salt bridge to the oxidizing agent D) the anode to cathode E) the salt bridge to the cathode
D) the anode to cathode Oxidation occurs at the anode and reduction at the cathode. This means electrons are removed from the anode and flow toward the cathode.
What type of light on the electromagnetic spectrum has the highest energy per photon? A) X-rays B) Visible light C) All light has the same energy D) Microwaves E) Gamma waves
E) Gamma waves Energy is directly related to frequency and inversely related to wavelength. Since gamma waves have the highest frequency and shortest wavelength, they have the highest energy.
Which of the following combinations would form a solution? I) Water and ethanol II) Sand and table salt III) Oxygen and nitrogen IV) Oil and vinegar A) I and II B) II and III C) III and IV D) II and IV E) I and III
E) I and III Because water and ethanol are both polar liquids, one dissolves in the other to form a liquid-liquid solution. The air around us has a uniform composition at a given altitude, and is made up of a gaseous homogeneous mixture (solution) of primarily oxygen and nitrogen.
Which element has the ground state electron configuration [Xe]6s²4f¹⁴5d⁴? A) W B) Pm C) Mo D) Np E) Re
A) W
Which of the following reactions is a double displacement reaction? A) HCl (g) → H₂ (g) + Cl₂ (g) B) HCl (aq) + NaOH (aq) → H₂O (l) + NaCl (aq) C) Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g) D) HCl (g) + C₅H₁₀ (g) →C₅H₁₁Cl (g)
B) HCl (aq) + NaOH (aq) → H₂O (l) + NaCl (aq)
Elements that are most similar in their properties are found _____ A) in the same period. B) in the same group. C) have the same electron configurations. D) to occur randomly throughout the table. E) diametrically opposite each other on the periodic table.
B) in the same group.
What type of reaction is represented by the following equation: BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq) A) combination B) decomposition C) double displacement D) single displacement
C) double displacement This is a double displacement reaction, which involves two ionic compounds that react and form two new ionic compounds. The cations from the reactants "switch" places.
Classify the following reaction: Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g) A) synthesis B) decomposition C) combustion D) single displacement (replacement) E) double displacement (replacement)
D) single displacement (replacement)
Which atom in the Br-F molecule has a partial negative charge (δ⁻)? A) F B) Br C) Both D) Neither
A) F Partial charges are determined by the relative electronegativities of the atoms in a molecule; the more electronegative atom, which is F, has a partial negative charge.
Which of the following has two valence electrons? A) hydrogen B) carbon C) aluminum D) strontium
D) strontium
What type of forces hold the atoms together in a sample of KCl? A) covalent bonds B) ionic bonds C) hydrogen bonds D) dipole-dipole interactions E) dispersion forces
B) ionic bonds Ionic bonding is the electrostatic attraction between two oppositely charged ions. Potassium forms K⁺ ions and chlorine forms Cl⁻ ions. Therefore KCl involves ionic bonding.
The symbol Hg represents the element _____ A) hydrogen B) mercury C) helium D) holmium E) sea borgium
B) mercury
A single electron in an orbital has quantum numbers n = 2, ℓ = 0, mℓ = 0, ms = +½. What are the quantum numbers for the next electron added to this atom? A) n = 2, ℓ = 1, mℓ = 0, ms = +½ B) n = 2, ℓ = 0, mℓ = 0, ms = -½ C) n = 2, ℓ = 0, mℓ = 0, ms = +½ D) n = 2, ℓ = 1, mℓ = 0, ms = -½ E) n = 2, ℓ = 1, mℓ = 1, ms = -½
B) n = 2, ℓ = 0, mℓ = 0, ms = -½
Which of the following sets of quantum numbers is not allowed? A) n = 1, ℓ = 0, mℓ = 0 B) n = 4, ℓ = 0, mℓ = -1 C) n = 3, ℓ = 1, mℓ = 0 D) n = 2, ℓ = 0, mℓ = 0 E) n = 3, ℓ = 2, mℓ = -2
B) n = 4, ℓ = 0, mℓ = -1
A ground state atom of As could not have any electrons with which of the following configurations? A) n = 3, ℓ = 1, mℓ = 0, ms = +½ B) n = 4, ℓ = 2, mℓ = 0, ms = +½ C) n = 4, ℓ = 0, mℓ = 0, ms = +½ D) n = 3, ℓ = 2, mℓ = 0, ms = +½ E) n = 4, ℓ = 1, mℓ = 0, ms = +½
B) n = 4, ℓ = 2, mℓ = 0, ms = +½
What is the correct molecular geometry of NH₃ according to Valence Shell Electron Pair Repulsion Theory? A) trigonal planar B) trigonal pyramidal (pyramidal) C) bent D) tetrahedral
B) trigonal pyramidal (pyramidal)
Write the chemical formula for chromium(VI) hypobromite
Cr(BrO)₆
What is the smallest whole-number coefficient for H₂S when the equation H₂S + MnO₄⁻ → Mn²⁺ + SO₄²⁻ is balanced in acidic solution?
5 In the equation S increases in oxidation number from -2 to +6, losing 8 electrons, and Mn decreases in oxidation number from +7 to +2, gaining 5 electrons. The only way to balance the electrons is to give H₂S a coefficient of 5 and MnO₄⁻ a coefficient of 8, resulting in a transfer of 40 electrons in the balanced equation.
When butanol (C₄H₉OH) is burned in oxygen, CO₂ and H₂O are the products. What is the coefficient in front of the O₂ in the balanced equation (using only whole numbers and the lowest whole number ratio)?
6 Matter is conserved in a chemical reaction. Balanced equations contain the same number of atoms of each element on each side of the equation. The balanced equation for this reaction is: C₄H₉OH + 6 O₂ → 4 CO₂ + 5 H₂O.
Which of the following is not permitted as a plausible orbital designation according to quantum theory. A) 1p B) 4f C) 3p D) 5p
A) 1p An orbital is designated by assigning a value for the principal quantum number (n) to identify the shell and a value for the angular quantum number (l) to identify the subshell. A 1p orbital is not permitted as p orbitals first occur in the n = 2 shell.
Which one of the following reactions would produce the largest amount of heat per mole of oxygen? A) 2 Ca (s) + O₂ (g) → 2 CaO (s) ∆H° = -635 kJ/mol B) CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g) ∆H° = -802 kJ/mol C) 2 CH₃OH (l) + 3 O₂ (g) → 2 CO₂ (g) + 4 H₂O(g) ∆H° = -1280 kJ/mol D) 2 Pb(s) + 3 O₂ (g) → 2 SO₂ (g) + 2 PbO (s) ∆H° = -828 kJ/mol
A) 2 Ca (s) + O₂ (g) → 2 CaO (s) ∆H° = -635 kJ/mol Calculate the enthalpy per mole of oxygen for each option. The reaction enthalpy is per mole of reaction. -635 kJ / 1 mol = -635 kJ mol O₂
Identify the reactant that gets oxidized in the following reaction. 5C₂O₄²⁻(aq) + 2MnO₄⁻(aq) + 16H⁺(aq) → 2Mn²⁺(aq) + 8H₂O(l) + 10CO₂(g) A) C in C₂O₄²⁻ B) Mn in MnO₄⁻ C) C in CO₂ D) Mn in Mn²⁺ E) This is not an oxidation/reduction type of reaction.
A) C in C₂O₄²⁻ Oxidation involves the loss of electrons while reduction involves the addition of electrons. One method to determine if a transfer of electrons has occurred is to determine the oxidation number of an atom before and after a reaction. The oxidation number of C increases from +3 in C₂O₄²⁻ to +4 in CO₂ so this species lost electrons and was oxidized.
Which of the following is a physical change? A) Condensation forms on cold glass. B) Glass reacts with hydrofluoric acid. C) A ground glass joint slowly forms sodium silicate when exposed to NaOH. D) Cobalt salts dissociate in a piece of blue stained glass. E) Silica is hydrated, forming silicic acid.
A) Condensation forms on cold glass. Condensation is a phase change from gas to liquid and represents a physical change.
Which of the following is an example of an ionic bond? A) K - F B) C - H C) Kr - H D) C - F
A) K - F K-F is an ionic bond because the difference in electronegativity is greater than 1.5 and it is between a metal and a nonmetal.
Identify the reactant that gets reduced in the following reaction. 3ReO₄⁻(aq) + 7MnO₂(s) + 2H₂O(l) → 3Re(s) + 7MnO₄⁻(aq) + 4H⁺(aq) A) Re in ReO₄⁻ B) Mn in MnO₂ C) Re in Re(s) D) Mn in MnO₄⁻ E) This is not an oxidation/reduction type of reaction.
A) Re in ReO₄⁻ Oxidation involves the loss of electrons while reduction involves the addition of electrons. One method to determine if a transfer of electrons has occurred is to determine the oxidation number of an atom before and after a reaction. The oxidation number of Re decreases from +5 in ReO₄⁻ to 0 in Re(s). This species gained electrons and was reduced.
Which of the following electron configurations is incorrect? A) S [Ne]3s³3p⁴ B) Sn [Kr]5s²4d¹⁰5p² C) Rb [Kr]5s¹ D) V [Ar]4s²3d³ E) I [Kr]5s²4d¹⁰5p⁵
A) S [Ne]3s³3p⁴
Of the following compounds, which contains a metalloid? A) SiF₄ B) SCl₂ C) In₂O₃ D) Sn(C₂H₅)₄ E) Bi₂S₃
A) SiF₄ Metalloids are elements that have properties of both metals and nonmetals. The metalloids are: B, Si, Ge, As, Sb, Te and Po.
If E°(red) of a given half-cell is more negative than E°(red) for a standard hydrogen electrode, the half-cell will: A) Tend to oxidize B) Tend to reduce C) Be at equilibrium D) Not enough info
A) Tend to oxidize The half cell with the higher E°(red) in a galvanic cell will be reduced, so if a half-cell has a more negative E°(red) than a standard hydrogen electrode, it will tend to oxidize while hydrogen ion is reduced.
In two chemical reactions, 4.0 grams of oxygen combine with 3.0 grams of carbon to form one compound, and 8.0 grams of oxygen combine with 3 grams of carbon to form another. This can be explained by: A) The law of multiple proportions B) The law of definite proportions C) The law of conservation of mass D) The law of conservation of energy
A) The law of multiple proportions
The atomic mass of germanium (Ge) on the periodic table is 72.630 amu. Which of the following best explains why the atomic mass is a fraction between 72 and 73? A) The presence of different isotopes B) The presence of different isomers. C) The formation of different ions. D) The presence of different allotropes. E) The presence of different amounts of protons.
A) The presence of different isotopes The atomic mass is an average that represents the abundance of each isotope.
True or false: two electrons can simultaneously occupy the same (n,ℓ,mℓ) orbital. A) True B) False
A) True The Pauli exclusion principle states that no two electrons in a given atom can share the same set of four quantum numbers (n, ℓ, mℓ, ms). Two electrons may share the first three quantum numbers (n, ℓ, mℓ) as long as their ms (spin) quantum numbers are not the same, so this statement is true.
Which of the following is the electron configuration for In? A) [Kr]5s²4d¹⁰5p¹ B) [Ar]5s²4d¹¹ C) [Ar]5s²5p¹ D) [Ar]5s²4d¹⁰5p¹ E) [Kr]5s²5p¹
A) [Kr]5s²4d¹⁰5p¹
Which of the following is a chemical change? A) cooking an egg B) mixing oil and water C) tearing a piece of paper D) watching a DVD
A) cooking an egg
What type of forces hold the atoms together in a sample of CH₂F₂? A) covalent bonds B) ionic bonds C) hydrogen bonds D) dipole-dipole interactions E) dispersion forces
A) covalent bonds
Quicklime, CaO, is an important substance used in making mortar. What kind of bonds are present in this compound? A) ionic B) covalent C) metallic D) coordinate
A) ionic
What is the balanced reaction for the cell diagram below? Al(s) | Al³⁺(aq) || Cd²⁺(aq) | Cd(s) A) Al³⁺(aq) + Cd(s) → Al(s) + Cd²⁺(aq) B) 2 Al(s) + 3 Cd²⁺(aq) → 2 Al³⁺(aq) + 3 Cd(s) C) 3 Al³⁺(aq) + 2 Cd(s) → 3 Al(s) + 2 Cd²⁺(aq) D) Al(s) + Cd²⁺(aq) → Al³⁺(aq) + Cd(s) E) 2 Al³⁺(aq) + 3 Cd(s) → 2 Al(s) + 3 Cd²⁺(aq)
B) 2 Al(s) + 3 Cd²⁺(aq) → 2 Al³⁺(aq) + 3 Cd(s) The cell diagram Al(s) | Al³⁺(aq) || Cd²⁺(aq) | Cd(s) represents the oxidation of Al at the anode and the reduction of Cd²⁺ at the cathode, with the following overall balanced reaction: 2 Al(s) + 3 Cd²⁺(aq) → 2 Al³⁺(aq) + 3 Cd(s)
Write the balanced equation for the reaction of solid potassium chlorate decomposing to form solid potassium chloride and oxygen gas. A) KClO₃ (s) → KCl (s) + 3 O (g) B) 2 KClO₃ (s) → 2 KCl (s) + 3 O₂ (g) C) KClO₄ (s) → KCl (s) + 2 O₂ (g) D) KClO₄ (s) → KCl (s) + 4 O (g)
B) 2 KClO₃ (s) → 2 KCl (s) + 3 O₂ (g)
Which one of the following best describes the difference between molar mass and formula weight? A) Formula weights are measured in grams per mole, while molar masses are measured in atomic mass units. B) A formula weight is the mass of one molecule or formula unit while a molar mass is the mass of one mole of molecules or formula units. C) Molar masses only describe the mass of ionic compounds, while formula weights can describe any compound. D) There is no difference between molar masses and formula weights.
B) A formula weight is the mass of one molecule or formula unit while a molar mass is the mass of one mole of molecules or formula units.
In the following chemical reaction, which element is the reducing agent? 2 IO₃⁻(aq) + 12 H⁺(aq) + 10 Ag(s) + 10 Cl⁻(aq) → 10 AgCl(s) + I₂(s) + 6H₂O(l) A) I B) Ag C) Cl D) H E) O
B) Ag Reducing agents lose electrons and are oxidized. In this reaction, Ag loses an electron to become Ag⁺.
A molecular cluster is formed from iron atoms and carbon monoxide (CO) molecules. If the molar mass of a cluster is 503.6 g/mol, and its empirical formula is Fe(CO)₄, how many iron atoms does the cluster contain? A) 1 B) 2 C) 3 D) 4 E) 5
C) 3 The relative mass of an Fe(CO)₄ formula unit is 167.8 g/mol. Three of these units would sum to a 503.6 g/mol cluster.
A state function is best described as A) A function that depends on what route is taken between start and finish. B) A function that is independent of the amount of substance. C) A function that depends only on the starting point and ending point of a process. D) A function that only depends on the end point of a process.
C) A function that depends only on the starting point and ending point of a process.
Identify the reactant that gets oxidized in the following reaction. 2Al(s) + 6HCl(aq) → 2AlCl₃(aq) + 3H₂(g) A) H in HCl B) Cl in HCl C) Al in AlCl₃ D) Al in Al(s) E) H in H₂
D) Al in Al(s) Oxidation involves the loss of electrons while reduction involves the addition of electrons. One method to determine if a transfer of electrons has occurred is to determine the oxidation number of an atom before and after a reaction. The oxidation number of Al increases from 0 in Al(s) to +3 in AlCl₃. This species lost electrons and was oxidized.
Which choice correctly identifies the oxidation numbers (O.N.) for each element in Ca(NO₃)₂? A) Ca = 0, N = 0, O = 0 B) Ca = 0, N = +5, O = -2 C) Ca = +2, N = +5, O = -6 D) Ca = +2, N = +5, O = -2 E) Ca = +4, N = +5, O = -2
D) Ca = +2, N = +5, O = -2 The charge on the NO₃⁻ ion is -1, so Ca must have a charge of +2 and an O.N. of +2. O always has a O.N. of -2 for compounds other than peroxides, which means N must have an O.N. of +5.
Red light has a _____ frequency and a _____ wavelength than ultraviolet rays. A) Higher, shorter B) Higher, longer C) Lower, lower D) Lower, longer E) Lower, shorter
D) lower, longer As can be seen on the electromagnetic spectrum, red light (and all visible light) has a lower frequency, and therefore a longer wavelength, than ultraviolet rays.
Which of the following measures the average kinetic energy of a system? A) enthalpy B) internal energy C) heat D) temperature E) specific heat capacity
D) temperature Temperature is an intensive physical property measuring the average kinetic energy of a substance through the calibrated thermal expansion of mercury or dyed alcohol.
What quantum mechanics principle states that electrons are added to atomic orbitals with the same energy so that each orbital is singularly occupied with electrons having the same spin? A) Schrödinger's equation B) Heisenberg uncertainty principle C) Pauli exclusion principle D) Aufbau principle E) Hund's rule
E) Hund's rule Hund's rule states that electrons are added to the atomic orbitals with the same energy levels (degenerate orbitals) in such a way that each orbital is occupied by a single electron with the same spin (either +½ or -½) before any orbital can be occupied by two electrons.
Because electron energy levels are quantized, which of the following is true? I) Atomic emission spectra are a series of discrete lines. II) Atomic emission spectra are continuous. III) Electrons may only occupy a discrete set of energy levels. IV) Electrons may occupy a continuous range of energy levels. A) I B) II C) III D) II and IV E) I and III
E) I and III The quantization of electron energy levels leads to a set of discrete transitions between those levels, which produces a set of discrete emission lines at specific wavelengths of light.
Excited hydrogen atoms emit radiation in which region(s) of the electromagnetic spectrum? A) IR only B) visible only C) UV only D) visible and UV E) IR, visible, and UV
E) IR, visible, and UV Excited hydrogen atoms are capable of emitting radiation with wavelengths from 100 nm to 10,000 nm; this section of the electromagnetic spectrum includes IR, visible, and UV radiation.
Which of the following sets of elements and symbols is paired correctly? A) potassium, P B) sodium, S C) copper, Co D) gold, Gd E) silicon, Si
E) silicon, Si
What is the correct IUPAC name for Cr(BrO₃)₃?
chromium(III) bromate
What is the correct IUPAC name for IrPO₄?
iridium(III) phosphate
What is the correct IUPAC name for Fe(IO₄)₂?
iron(II) periodate
In the redox reaction 6 Fe²⁺ + Cr₂O₇²⁻ + 14 H⁺ → 2 Cr³⁺ + 6 Fe³⁺ + 7 H₂O, what is the reducing agent? A) Fe²⁺ B) Cr₂O₇²⁻ C) H⁺ D) Cr³⁺ E) Fe³⁺
A) Fe²⁺ Fe²⁺ increases in oxidation number from +2 to +3 and the Cr in Cr₂O₇²⁻ decreases in oxidation number from +6 to +3. Therefore Cr is being reduced, and Fe²⁺ is the reducing agent.
Which of the following is true concerning ψ²? A) ψ² describes the probability of finding an electron in space. B) ψ² describes the exact path of electron motion in an orbital. C) ψ² describes the electronic structure of the atom according to the Bohr model. D) ψ² describes the exact volume of an atom. E) ψ² describes the size of an atom.
A) ψ² describes the probability of finding an electron in space. While the wave function ψ describes the overall state of a quantum system, the square of the wavefunction (ψ²) gives the probability of finding an electron in a given region of space.
Which of these scenarios contains an exact number? A) You count 10 people in a room. B) You weigh an apple to be 10 grams. C) You measure the tree to be 10 meters high. D) You determine the volume of the pool to be 10 liters.
An exact number is a number that is either defined or can be counted. 10 people is an exact number.
Which of the following best defines a scientific theory? A) An 'if, then' statement that can be tested by science. B) A model used to explain how or why a phenomenon occurs. C) A unifying concept; often a mathematical description of the way in which a natural phenomenon occurs. D) A piece of knowledge about the outside world received through the senses or instrumentation. E) Something that is known to be consistent with reality; that which has not been falsified.
B) A model used to explain how or why a phenomenon occurs.
Which one of the following would form a precipitate with PO₄³⁻ ions in aqueous solution? A) K⁺ B) NH₄⁺ C) Ca²⁺ D) None of these would form a precipitate.
C) Ca²⁺ Calcium phosphate is insoluble in water. Although phosphates are typically insoluble in water, exceptions are potassium phosphate and ammonium salts.
Write the chemical formula for chromium(III) cyanide
Cr(CN)₃
Under which process does an atom demonstrate the largest increase in size in one step? A) Gaining its first electron to become a -1 anion. B) Gaining its second electron to become a -2 anion. C) The size of an atom is constant. D) Losing its first electron to become a +1 cation. E) Losing its second electron to become a +2 cation.
A) Gaining its first electron to become a -1 anion.
If you have 5 mol H₂ and 2 mol N₂, what is the limiting reagent in the reaction below? 3 H₂(g) + N₂ (g) → 2 NH₃ (g) A) H₂ B) N₂ C) NH₃ D) Both reactants are limiting.
A) H₂ The limiting reactant can be determined by calculating the amount of the other reactant that would be necessary for the reaction to occur. 1.67molN2 6molH2 H₂ is the limiting reactant because there isn't enough of it to completely react with the amount of N₂.
What type of reaction is represented by the following equation: 2Na(s) + Cl₂(g) → 2NaCl(s) A) combination B) decomposition C) double displacement D) single displacement
A) combination This is a combination reaction, involves two compounds reacting to form one new compound. This type of reaction is also known as a synthesis reaction.
Italian dressing contains olive oil and vinegar, which will separate out from each other if left to sit. This makes the dressing a: A) heterogeneous mixture B) Homogeneous mixture C) Both (A) and (B) D) None of the above
A) heterogeneous mixture Italian dressing is a heterogeneous mixture that has a difference in composition within the mixture.
An electron is shown to occupy a d orbital. Which of the following sets of quantum numbers can describe this electron? A) n = 3, ℓ = 2, mℓ = -2 B) n = 4, ℓ = 1, mℓ = 2 C) n = 5, ℓ = 1, mℓ = 0 D) n = 3, ℓ = 1, mℓ = -1 E) n = 4, ℓ = 3, mℓ = -3
A) n = 3, ℓ = 2, mℓ = -2
An exothermic reaction causes the surroundings to A) warm up B) become acidic C) condense D) decrease in temperature E) release CO₂
A) warm up An exothermic reaction transfers energy from the system to the surroundings. That tells us the surroundings will get warmer.
Glucose is an important biological molecule with the molecular formula C₆H₁₂O₆. What is its empirical formula? A) CHO B) CH₂O C) C₂HO₂ D) C₆H₁₂O₆ E) Not enough info
B) CH₂O
Which periodic trend quantifies the amount of energy required to remove an electron from a neutral, gaseous atom? A) Atomic Radius B) Ionization Energy C) Ionic Radius D) Electron Affinity E) Electronegativity
B) Ionization Energy
Which atom in the O-F bond has a partial positive charge (δ⁺)? A) F B) O C) Both D) Neither
B) O Partial charges are determined by the relative electronegativities of the atoms in a bond; the less electronegative atom, which is O, has a partial positive charge.
The Millikan oil drop experiment determined: A) The mass of the electron B) The charge of the electron C) The mass of the proton D) Both (A) and (B)
B) The charge of the electron
When boiling water on a natural gas (methane) burner, which of the following processes converts chemical potential energy to heat? A) The pressure of the natural gas B) The combustion reaction between methane and oxygen. C) Breaking the carbon-hydrogen bonds in methane D) Redox reactions that generate a potential difference E) Alternating electromotive force
B) The combustion reaction between methane and oxygen. Combustion of hydrocarbons, such as the methane in natural gas, releases large amounts of heat because the chemical bonds being formed are stronger than the bonds broken.
A voltaic cell is prepared where copper metal is oxidized to copper(II) and silver(I) is reduced to silver metal. Which of the following reactions occurs at the anode? A) 2 Cu(s) → 2 Cu²⁺(aq) + e⁻ B) Cu²⁺(aq) + 2e⁻ → Cu(s) C) Cu(s) → Cu²⁺(aq) + 2e⁻ D) Ag⁺(aq) + e⁻ → Ag(s) E) Ag(s) → Ag⁺(aq) + e⁻
C) Cu(s) → Cu²⁺(aq) + 2e⁻ Oxidation, which is the loss of electrons, occurs at the anode. The correctly balanced half-reaction for the oxidation of Cu isCu(s) → Cu²⁺(aq) + 2e⁻
Determine the correct formula for iron(III) perchlorate. A) Fe₂ClO₄ B) Fe₂(ClO₄)₃ C) Fe(ClO₄)₃ D) Fe₃(ClO₄)₂
C) Fe(ClO₄)₃ The (III) in iron(III) perchlorate indicates that the iron ion has a 3+ charge. Perchlorate is a polyatomic ion with a -1 charge. Three perchlorate ions would be needed to balance the charge on iron.
Give the balanced equation for solid iron(III) sulfide reacting with gaseous hydrogen chloride to form solid iron(III) chloride and hydrogen sulfide gas. A) Fe₂S₃ (s) + HCl (g) → FeCl₃ (s) + H₂S (g) B) Fe₂(SO₄)₃ (s) + 6 HCl (g) → 2 FeCl₃ (s) + 3 H₂S (g) C) Fe₂S₃ (s) + 6 HCl (g) → 2 FeCl₃ (s) + 3 H₂S (g) D) Fe₃S (s) + HCl (g) → Fe₃Cl (s) + H₂S (g)
C) Fe₂S₃ (s) + 6 HCl (g) → 2 FeCl₃ (s) + 3 H₂S (g)
Which of the following is an example of a covalent bond? A) K - Cl B) Al - Cl C) H - Cl D) Al - Al
C) H - Cl Covalent bonds are typically formed between two nonmetals.
Which of the following describes a chemical change involving water? A) H₂O(l) → H₂O(s) B) H₂O(s) → H₂O(g) C) H₂O(l) → H₂(g) + ½O₂(g) D) H₂O(g) → H₂O(l)
C) H₂O(l) → H₂(g) + ½O₂(g) A chemical change would involve the atoms found in a water molecule rearranging to form a new molecule or molecules with different composition(s). A physical change would involve the water molecules changing their state of matter but still remaining water molecules.
What is the noble gas core in the electron configuration for Sb? A) Ne B) Ar C) Kr D) Xe E) Rn
C) Kr The noble gas core for a given element is the last noble gas filled in the periodic table prior to the given element. Here, the last noble gas prior to Sb is Kr, so that is its noble gas core.
Which of the following is NOT a statement of the First Law of Thermodynamics? A) Energy can neither be created nor destroyed. B) The total energy of the universe is constant. C) The total entropy of an isolated system cannot decrease. D) Energy can only be converted from one form to another.
C) The total entropy of an isolated system cannot decrease. The First Law of Thermodynamics states that energy cannot be created nor destroyed. The statement that entropy must never decrease for an isolated system is based on the Second Law of Thermodynamics.
In the photoelectric effect, if the intensity of light shone on a metal increases, what will happen? A) Ejected electrons will be faster B) Ejected electrons will be slower C) There will be more electrons ejected D) There will be fewer electrons ejected E) No change
C) There will be more electrons ejected The intensity of light is directly related to the number of electrons ejected. Therefore, if the intensity of light increases, there will be more electrons ejected.
What is the purpose of a salt bridge? A) It is how the electrons move B) To react with the metals in the oxidation and reduction reactions C) To provide charge balance to each cell D) Salt bridges are not required in voltaic reactions E) To provide a path for the metallic ions to travel through
C) To provide charge balance to each cell As the voltaic cell operates, the anode will create positive metallic ions and the cathode will deplete positive metallic ions. The salt bridge is needed to balance this charge imbalance that occurs.
Which of the following sets of quantum numbers can describe a 3p electron? A) n = 1, ℓ = 3, mℓ = 1 B) n = 3, ℓ = 2, mℓ = 1 C) n = 3, ℓ = 1, mℓ = 1 D) n = 3 , ℓ = 0, mℓ = 1 E) n = 2, ℓ = 3, mℓ = 1
C) n = 3, ℓ = 1, mℓ = 1
Neutral atoms of all isotopes of a given element have the same A) number of protons and neutrons B) number of neutrons C) number of electrons D) mass numbers E) masses
C) number of electrons Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons and electrons.
Write the chemical formula for chromium(III) sulfate
Cr₂(SO₄)₃
What is the molecular formula of a compound with an empirical formula of CH and a molar mass of 78.1 g/mol? A) C₆H B) C₂H₂ C) C₂H₆ D) C₆H₆
D) C₆H₆ An empirical formula shows the simplest whole number ratio of each element to one another in the formula unit or molecule. The molar mass of CH is 13.02 g. Divide the molar mass of the unknown compound by the molar mass of the empirical formula to find the total number of CH units in the molecular formula. 78.1g/13.02g=6
Terephthalic acid is a chemical used to make polyesters, including disposable water bottles. It has the empirical formula C₄H₃O₂. The molar mass of terephthalic acid is 166 g/mol. What is its chemical formula? A) C₄H₃O₂ B) C₁₂H₉O₆ C) C₈H₈O₈ D) C₈H₆O₄ E) C₁₀H₁₂O₈
D) C₈H₆O₄ An empirical formula shows the simplest whole number ratio of each element to one another. Four carbon atoms, three hydrogen atoms, and two oxygen atoms have a relative mass of 83 g/mol. If the molar mass of terephthalic acid is two of these units (2 x 83 = 166 g/mol), it would have the molecular formula of C₈H₆O₄.
Which one of the following is the most electronegative atom? A) C B) N C) O D) F
D) F
Which of the following bonds is a nonpolar covalent bond? A) H - F B) N - F C) F - Cl D) F - F
D) F - F In order to be nonpolar, the two atoms in the chemical bond need to have the same electronegativity.
What is the definition of a scientific law? A) It is witnessed and can be recorded. B) It gives an overall explanation of a natural phenomenon. C) It involves both a number and a unit. D) It summarizes an observable behavior.
D) It summarizes an observable behavior.
Which of the following is an extensive physical property of matter? A) Boiling point B) Reactivity C) Density D) Length E) Freezing point
D) Length Length changes based on how much of a substance is present. It can also be observed through physical means.
Rank the following atoms in order of increasing first ionization energies (i.e., lowest to highest): Rb, F, Mg, B, N. A) F < N < B < Mg < Rb B) Rb < Mg < F < N < B C) Mg < Rb < F < N < B D) Rb < Mg < B < N < F E) Rb > B > N > F > Mg
D) Rb < Mg < B < N < F In general, first ionization energy decreases down a group and increases across a period.
Gasoline is composed of a variety of different liquid hydrocarbons, which do not separate as time passes. Gasoline is an example of a: A) heterogeneous mixture B) Chemical compound C) Chemical element D) Solution
D) Solution Gasoline is a homogeneous liquid-liquid mixture of a variety of different hydrocarbons, and other soluble additives. Therefore, it is a solution.
When water cools from 10 °C and then freezes to become ice, which of the following best describes describe the heat flow between the system and surroundings? A) The energy of the universe is decreasing because the water is cold. B) The energy of the universe is increasing because the energy had to be removed from the water C) The water is absorbing energy as its temperature decreases, and that energy was released by the surroundings. D) The water is releasing energy as its temperature decreases, and that energy is absorbed by the surroundings.
D) The water is releasing energy as its temperature decreases, and that energy is absorbed by the surroundings.
Which electron configuration violates Hund's rule? A) [He]2s²2px²2py²2pz¹ B) [He]2s²2px²2py¹2pz² C) [He]2s²2px¹2py²2pz² D) [He]2s²2px²2py² E) [He]2s²2px¹2py¹2pz²
D) [He]2s²2px²2py²
What type of calorimeter would be appropriate for measuring heats of combustion? A) constant temperature calorimeter B) differential scanning calorimeter C) coffee cup calorimeter D) bomb calorimeter
D) bomb calorimeter A bomb calorimeter is the best choice from this list to measure heats of combustion. Because gases will be produced by the combustion reaction, it makes sense to carry out this experiment in a fixed-volume configuration.