Module Two Chem 101 Problems
What is the correct IUPAC name for Ba(OH)₂?
barium hydroxide
What is the correct IUPAC name for CsI?
cesium iodide
What is the correct IUPAC name for S₂Cl₈?
disulfur octachloride
Draw the Lewis structure for ammonium (NH₄⁺). Does this molecule exhibit resonance?
image 13 no resonance
What is the correct IUPAC name for Fe(NO₂)₂?
iron (II) nitrite
What is the correct IUPAC name for As₄O₃?
tetraarsenic trioxide
The density of a solution that is 18.0% by mass lead nitrate [Pb(NO₃)₂] is 1.18 g/mL. Calculate the molarity of the lead nitrate solution.
0.64 M
Write the chemical formula for diarsenic trioxide
As2O3
Predict the chemical formula for the ionic compound formed by Au³⁺ and HSO₃⁻
Au(HSO3)3
The Lewis structure of carbonate (CO₃²⁻) is shown on the left below. What is the formal charge of the highlighted atom? (image 5) A. 0 B. -1 C. +1 D. -2 E. +2
B. -1
Which has the incorrect name-formula combination? A. Sulfur dioxide - SO2 B. iodine trifluoride - IF C. Nitrogen tribromide - NBr3 D. silicon tetrafluoride - SiF4
B. Iodine trifluoride - IF The name of a molecular compound must indicate the number of each atom in the formula. The prefix tri- indicates three. In this case, iodine trifluoride indicates that there are three fluoride atoms for each iodine atom. The formula would be IF₃.
A Lewis structure for ozone (O₃) is shown below on the left. Predict whether bonding angle A will be equal to, greater than, or less than the ideal bonding angle according to the VSEPR model. (image 25) A. equal B. greater than C. less than
C) Less than Correct, the lone pair and double bond on the central oxygen will cause the bond angle to become smaller Consider the additional electronic repulsions provided by the lone pairs and double bonds on the structure. This will result in Bond Angle A being less than the ideal bonding angle according to the VSEPR model.
Which of the following molecules has a bond order of 2.5 according to molecular orbital theory? A) H₂⁻ B) CN⁺ C) NO D) O₂
C) NO
Based on their positions in the periodic table, which of the following bonds is the most polar? A. O-F B. C-F C. B-F D. F-F
C. B-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.
What is the correct IUPAC name for Cr₂(SO₄)₃?
Chromium (III) sulfate
What is the correct IUPAC name for CoPO₄?
Cobalt (III) phosphate
What is the correct IUPAC name for Cu₂S?
Copper (I) sulfide
The molecular orbital energy diagram for N₂ is shown below. Based on this diagram, what is the bond order of N₂? (image 45) A. 1 B. 1.5 C. 2.5 D. 3 E. 0
D. 3
Which one of the following is the most electronegative atom? A) C B) N C) O D) F
D. F Fluorine is the most electronegative element.
What would be the bond order of the hypothetical molecule Ar₂?
0 Ar has a complete octet of electrons, meaning there is no donating/sharing electrons between Ar atoms
How many moles of KBr are there in 60.0 mL of 0.150 M KBr?
0.00900 mol
For each of the following antibiotics, determine how many moles of each compound are present for the given mass. How many moles of erythromycin (C₃₇H₆₇NO₁₃) are in 224.0 grams?
0.3052 mol
A solution is made using 111.5 g of dimethyl ether (MM = 46.07 g/mol) and 90.0 g of methanol (MM = 32.04 g/mol). What is the mole fraction of the dimethyl ether in the solution?
0.463
Calculate the mole fraction of water in a solution made by mixing 1.0 g of water and 2.0 g of ethyl alcohol (MM = 34.0g/mol).
0.49
Use the MO diagram (below) to calculate the bond order for I₂.
1
The compound PSI₃ is called phosphorothioic triiodide. Use the Lewis structure you drew in part e. what is the formal charge on the P atom?
1 The following solution may contain one or more values that are different from the problem provided to you, however, the steps to solve the problem are the same. .The formal charge on P is 5 - (4 + 0) = +1.
What is the concentration of lithium ions in 0.350 M Li₃PO₄?
1.05 M
An aqueous solution of saxitoxin (a toxin produced by harmful algal blooms) is made by dissolving 125 uL aliquot of 3.34× 10⁻⁶ M solution to a final volume of 100 mL. What is this diluted concentration in ppb? The molar mass of saxitoxin is 300 g/mol.
1.25 ppb
If 35.0 g of C₂H₅OH (MM = 46.07 g/mol) are added to a 500.0 mL volumetric flask, and water is added to fill the flask, what is the concentration of C₂H₅OH in the resulting solution?
1.52 M
A sample of seawater from a tidal estuary was found to contain a concentration of 825 mg of chloride ion per kg of seawater. If the density of the sample was 1.035 g/mL, what is the molarity of the chloride ion?
2.41 × 10⁻² M
how many ml of water should a chemist add if they prepare an 0.200 M aq solution with 30.2 g of NaCl. assume desnity of solution is the same as water .
2580 mL.
How many carbon-oxygen σ bonds are present in the structure of the organic molecule shown? (image 36)
3 There are 3 carbon-oxygen σ bonds present in the structure. The molecule contains 2 carbon-oxygen single bonds (which equals 2 σ bonds) and one carbon-oxygen double bond (which equals 1 σ bond + 1 π bond) to give 3 σ bonds total.
What is the concentration in molarity of an aqueous solution which contains 20.01% by mass acetonitrile (MM = 41.05 g/mol)? The density of the solution is 0.810 g/mL.
3.95 M
How many mL of 0.600 M LiCl would be required to make a 0.0600 M solution of LiCl when diluted to 300.0 mL with water?
30.0 mL
Xenon is a noble gas that is capable of forming compounds. One of these compounds is XeBr₂Cl₂. What is the total number of valence electrons in the molecule?
36
How many π bonds are in the structure of the organic molecule below?(image 35)
4
The compound PSI₃ is called phosphorothioic triiodide. How many valence electrons does a P atom have?
5
What volume in mL of 0.3000 M NaCl solution is required to produce 0.1500 moles of NaCl?
500.0 mL
The compound PSI₃ is called phosphorothioic triiodide. How many valence electrons does an I atom have?
7
An aqueous solution of ethanol (MM = 46.07 g/mol) has a molality of 12.15 m and a density of 1.10 g/mL. What is the molarity of ethanol in the solution?
8.57 M
Percent by definition is parts per hundred. % (w/w) = (mass of solute/mass of solution) x 100. For very dilute solutions, chemists will often use parts per thousand or parts per million (ppm) or parts per billion (ppb). Calculate the concentration of a solution using each of these units. The legal limit of blood alcohol limit in most states is 0.080 grams per 100.0 grams of blood. What is this concentration in parts per million?
800 ppm
A solution is made using 79.9 g of phenol (MM = 94.11 g/mol) and 90.0 g of acetone (MM = 58.08 g/mol). What is the molality of the phenol in the solution?
9.43 m
A Lewis structure for SO₃ is shown below on the left. Predict whether bonding angle A will be equal to, greater than, or less than the ideal bonding angle according to the VSEPR model. (image 26) A. equal B. greater than C. less than
A) Equal Correct, the extra repulsion caused by all three double bonds will negate each other and result in no change to the bonding angle Consider the additional electronic repulsions provided by the lone pairs and double bonds on the structure. This will result in Bond Angle A being equal to the ideal bonding angle according to the VSEPR model.
What does the ring in the center of a benzene molecule represent? A) It means the π electrons are delocalized around the benzene ring. B) It means the π protons are delocalized around the benzene ring. C) It means the σ electrons are delocalized around the benzene ring. D) It means the σ protons are delocalized around the benzene ring.
A) It means the π electrons are delocalized around the benzene ring. Resonance is represented as a ring in the center of a molecule. It means that the π electrons are delocalized around the benzene ring.
A Lewis structure for the molecule benzene (C₆H₆) is shown below. Based on this structure, determine if the molecule is polar or nonpolar. (image 29)
A) Nonpolar Correct, the ring structure is symmetrical.
Write the chemical formula for aluminum fluoride
AlF3
If 35.0 g of CH₃OH (MM = 32.0 g/mol) are dissolved in 500.0 mL of solution, what is the concentration of CH₃OH in the solution? A) 0.0700 M B) 2.18 M C) 0.00218 M D) 0.458 M
B) 2.18 M
The molecular orbital energy diagram for N₂ is shown below. Based on this diagram, is the molecule paramagnetic or diamagnetic? A) paramagnetic B) diamagnetic
B) diamagnetic Paramagnetic molecules will have unpaired electrons. Diamagnetic molecules have all paired electrons. N₂ is diamagnetic.
What is the correct IUPAC name for BaI₂?
Barium iodide
100.0 mL of a 0.500 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution? A) 2.50 M B) 0.500 M C) 0.100 M D) 0.0250 M
C) 0.100 M
A Lewis structure for the hydronium ion (H₃O⁺) is shown below on the left. Predict whether bonding angle A will be equal to, greater than, or less than the ideal bonding angle according to the VSEPR model. (image 28) A. equal B. greater than C. less than
C) Less than Correct, the lone pair on the central oxygen will cause the bond angle to become smaller Consider the additional electronic repulsions provided by the lone pairs on the structure. This will result in Bond Angle A being less than the ideal bonding angle according to the VSEPR model.
Which one of the following bonds has the least ionic character? A. Li-Cl B. Na-Cl C. Ca-Cl D. B-Cl
D. B-Cl A bond between B-Cl would have the least ionic character because it is between two nonmetals.
A Lewis structure with placeholder central atom is shown below. If the charge of the molecule is -1, choose the possible identity or identities of the central atom. (image 4) A. F B. N, P or As C. C, Si, or Ge D. B or Al E. Cl, Br, I
E. Cl, Br or I
Write the chemical formula for iron(II) sulfate heptahydrate
FeSO4 . 7 H2O
Write the formula for sulfurous acid
H2SO3
Determine the correct formula for manganese(II) fluoride.
MnF₂ The (II) in manganese(II) fluoride indicates that the manganese ion has a 2+ charge. Fluoride has a -1 charge. Two fluoride ions would be needed to balance the charge on the manganese ion.
Write the chemical formula for dinitrogen tetroxide
N2O4
What is the correct IUPAC name for BaCr₂O₇?
barium dichromate
Draw the Lewis structure of XeCl₂ and then determine the hybridization of the central atom.
image 40 sp³d
What is the correct IUPAC name for FeCl₃ · 6H₂O?
iron(III) chloride hexahydrate
What is the correct IUPAC name for MnF₃?
manganese (III) fluoride
What is the correct IUPAC name for HNO₃(aq)?
nitric acid
What is the correct IUPAC name for KF · 2H₂O?
potassium fluoride dihydrate
What is the correct IUPAC name for Sr(NO₃)₂?
strontium nitrate
What is the correct IUPAC name for Ti(ClO₄)₄?
titanium (IV) perchlorate
Determine the number of valence electrons in cyanide (CN⁻) and then draw the corresponding Lewis structure. Please place the elements in the order that they are written.
valence e-= 10 image 9
What is the correct IUPAC name for VBrO₄?
vanadium (I) perbromate
Identify the HOMO in the MO diagram of C₂ (image 41)
π (2px and 2py). The HOMO is the highest energy (y-axis of the diagram) that contains electrons..
Identify the HOMO in the MO diagram of O₂ (shown below). (image 42)
π* (2px or 2py). The HOMO is the highest energy (y-axis of the diagram) that contains electrons.
The compound PSI₃ is called phosphorothioic triiodide. Use the Lewis structure you drew in part e, what is the formal charge on the S atom?
-1
The most common ion formed by bromine has a charge of
-1
To what volume (in mL) would you need to dilute 30.0 mL of a 1.35 M solution of NaI to make a 0.0700 M solution of NaI?
579 mL
The compound PSI₃ is called phosphorothioic triiodide. How many valence electrons does a S atom have?
6
Write the chemical formula for hydrobromic acid
HBr
Predict the chemical formula for the ionic compound formed by NH₄⁺ and PO₄³⁻
(NH4)3PO4
The most common ion formed by magnesium has a charge of
+2
The most common ion formed by phosphorus has a charge of
-3
For each of the following antibiotics, determine how many moles of each compound are present for the given mass. How many moles of vancomycin (C₆₆H₇₅Cl₂N₉O₂₄) are in 62.5 grams?
0.0431 mol
If 25.0 mL of a 6.00 M HCl solution is diluted to 2.00 L, what is the molarity of the new solution?
0.0750 M
convert the concentration of 0.700 M Na2SO4 to g/ml
0.0994 g Na₂SO₄ / mL.
100.0 mL of a 0.500 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution?
0.100 M
For each of the following antibiotics, determine how many moles of each compound are present for the given mass. How many moles of tetracycline (C₂₂H₂₄N₂O₈) are in 52.1 grams?
0.117 mol
What volume (in L) of 1.6 M Na₃PO₄ would be required to obtain 0.60 moles of Na⁺ ions?
0.13 L
600.0 mL of a 0.300 M solution of LiCl is diluted to 900.0 mL. What is the new concentration of the solution?
0.200 M
What volume (in L) of 1.5 M Na₂CO₃ would be required to obtain 0.65 moles of Na⁺ ions?
0.22 L
What is the concentration in molarity of an aqueous solution which contains 1.41% by mass acetone (MM = 58.08 g/mol)? The density of the solution is 0.971 g/mL.
0.236 M
molarity of potassium ions in a 0.122 M K2CrO4 solution
0.244 mol K⁺ ions / L.
What is the concentration of a solution made with 0.150 moles of KOH in 400.0 mL of solution?
0.375 M
what volume in L of a 0.724 M Nal solution contains 0.405 mol of Nal
0.559 L.
what is the mass in g of NaCN in 120.0 ml of a 2.40x10^(-5) M solution
1.41 × 10⁻⁴ g NaCN.
What is the %v/v of a solution made from 141.1 g of ethylene glycol (density is 1.11 g/mL) in water (density 1.00 g/mL) to form a total volume of 500.0 mL? You may assume the density of ethylene glycol does not change in the solution.
25.4 %
Xenon is a noble gas that is capable of forming compounds. One of these compounds is XeBr₂Cl₂. Use your Lewis structure from part b. How many electron domains are on the central atom? (image 32)
6
A Lewis structure for SO₃ is shown below on the left. Predict whether bonding angle A will be equal to, greater than, or less than the ideal bonding angle according to the VSEPR model. (image 27) A. equal B. greater than C. less than
A) Equal Correct, the extra repulsion caused by all three double bonds will negate each other and result in no change to the bonding angle Consider the additional electronic repulsions provided by the lone pairs and double bonds on the structure. This will result in Bond Angle A being equal to the ideal bonding angle according to the VSEPR model.
Determine the number of sigma (σ) and pi (π) bonds in the molecule shown on the left below. (image 37) A. 24 sigma 7 pi B. 7 sigma 5 pi C. 24 sigma 22 pi D. 7 sigma 7 pi E. 24 sigma 5 pi
A. 24 sigma and 7 pi Remember a single bond = 1 σ; a double bond = 1 σ + 1 π; a triple bond = 1 σ + 2 π. This molecule contains 7 double bonds, so this is 7π bonds and 7σ. This molecule also contains 17 single bonds, so there are 17σ. This is a total of 7π and 24σ.
Which atom in the molecule ClF would have a partial positive charge (δ⁺)? A. Cl B. F C. Both D. Neither
A. Cl Partial charges are determined by the relative electronegativities of the atoms in a molecule; since you are looking for the atom with a positive partial charge, you should choose the atom that is the least electronegative. This is Cl.
What type of bonding is present in C₁₂H₂₂O₁₁? A. covalent bonds only B. ionic bonds only C. both covalent and ionic bonds D. neither covalent or ionic
A. Covalent bonds only C₁₂H₂₂O₁₁ is a covalent compound. All atoms are held together by the sharing of electrons, which are covalent bonds.
A Lewis structure for CH₃CHCH₂ is shown below on the left. Predict whether bonding angles A and B will be equal to, greater than, or less than the ideal bonding angles according to the VSEPR model. (image 24) A. A-equal, B-equal B. A- greater than, B-less than C. A- less than, B- greater than D. A- less than, B- less than E. A- greater than, B- greater than
B) A: greater than, B: less than Correct, the extra repulsion from the double bond on the middle carbon will cause bond angle A to become greater, consequentially making bond angle B smaller Consider the additional electronic repulsions provided by the lone pairs and double bonds on the structure. This will result in Bond Angle A being greater than the ideal bonding angle and Bond Angle B being less than the ideal bonding angle according to the VSEPR model .
Which atomic orbitals from carbon hybridize to form the bonds in CH₄? A) 1s, 2p_x, 2p_y, 2p_z B) 2s, 2p_x, 2p_y, 2p_z C) 3s, 3p_x, 2p_y, 2p_z D) 2s, 2p_x, 2p_y
B. 2s, 2p_x, 2p_y, 2p_z Draw the orbital energy diagram for C to find where its valence electrons are. They are found in 2s,2pₓ,2py,2pz2s,2pₓ,2py,2pz.
Which atom in the C-Br bond has a partial positive charge (δ⁺)? A. Br B. C C. Both D. Neither
B. C Partial charges are determined by the relative electronegativities of the atoms in a bond; the less electronegative atom, which is C, has a partial positive charge.
Which hybrid orbitals overlap in the C - O bond in CF₂O? A) Csp² - Os B) Csp² - Osp² C) Csp² - Osp³ D) Csp³ - Osp³ E) Csp³ - Osp
B. Csp² - Osp² In the Lewis structure of COF₂ both the C and O atoms are sp² hybridized. The C-O sigma bond is formed between the Csp² orbital and the O-sp² orbital.
Choose the structure that has the formal charge correctly assigned. (image II) A. I B. II C. III D. IV
B. II II. Formal charge can be calculated using the following equation: formal charge = [# of valence electrons] - [electrons in lone pairs + 1/2 the number of bonding electrons]. For protonated acetone, the oxygen has 6 valence electrons, 2 electrons in lone pairs and 6 bonding electrons, therefore the formal charge = 6-[2+1/2(6)] = +1.
Which of the following compounds contains a polyatomic ion? A. CO2 B. MgCO3 C. SiO2 D. CO
B. MgCO3 A polyatomic ion is composed of multiple covalently bonded atoms. CO₃²⁻ is a polyatomic ion composed of a carbon atom and three oxygen atoms.
Which atom in the N-H bond has a partial negative charge (δ⁻)? A. H B. N C. Both D. Neither
B. N Partial charges are determined by the relative electronegativities of the atoms in a molecule; since you are looking for the atom with a positive negative charge, you should choose the atom that is the most electronegative. This is N.
Which atom in the P-Cl bond has a partial positive charge (δ⁺)? A. Cl B. P C. Both D. Neither
B. P Partial charges are determined by the relative electronegativities of the atoms in a bond; the less electronegative atom, which is P, has a partial positive charge.
Classify the following compounds as ionic or covalent: KCl, CrCl₃, Cl₂O. A. ionic, covalent, covalent B. ionic, ionic, covalent C. covalent, covalent, ionic D. ionic, covalent, ionic
B. ionic, ionic, covalent Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two nonmetals
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 Trigonal pyramidal (pyramidal). Ammonia has three groups and one set of lone pairs bound to a central atom, which affords a trigonal pyramidal, or pyramidal, molecular geometry based on Valence Shell Electron Pair Repulsion Theory.
Complete the MO diagram to determine if BN is paramagnetic or diamagnetic.
BN is diamagnetic. BN has 8 electrons in the valence shell. All the electrons in this molecule are paired.
Complete the MO diagram (below) to determine if BO⁻ is paramagnetic or diamagnetic.
BO⁻ is diamagnetic. BO⁻ has 10 electrons in the valence shell. There are no unpaired electrons in this ion.
Write the chemical formula for barium nitride
Ba3N2
What is the correct formula for barium phosphate?
Ba₃(PO₄)₂ Barium forms ions with a +2 charge and the phosphate polyatomic ion has a -3 charge. It would take three barium ions to balance the charge of two phosphate ions. This is the lowest number of each ion to reach a neutral formula unit.
The Lewis structure of ozone (O₃) is shown on the left below with numbers on the corresponding atoms. Choose the correct set of formal charges of the atoms in ascending order of atom number. (image 6) A. 1=0, 2=0, 3=0 B. 1=-1, 2=0, 3=+1 C. 1=0, B=+1, C=-1 D. 1=+1, B=-1, C=0 E. 1=-2, 2=+1, 3=+1
C) #1 = 0, #2 = +1, #3 = -1
Which hybrid orbitals overlap in the C - N bond in CO(NH₂)₂? A) Csp² - Ns B) Csp² - Nsp² C) Csp² - Nsp³ D) Csp³ - Nsp³ E) Csp³ - Nsp
C) Csp² - Nsp³ In the Lewis structure of CO(NH₂)₂ both the C and O atoms are sp² hybridized, and each N atom is sp³ hybridized. The orbitals within the C-N bond involve the C-sp² orbital forming a sigma bond with each N-sp³ orbital.
Xenon is a noble gas that is capable of forming compounds. One of these compounds is XeBr₂Cl₂. Is the molecule polar? A) Yes, it is polar. B) No, the molecule is nonpolar. C) Depending on how the atoms are connected, the molecule can be polar or nonpolar.
C) Depending on how the atoms are connected, the molecule can be polar or nonpolar. Some molecules can have the atoms connected in different ways. For this molecule, there are two ways to connect the Br and Cl atoms to the Xe atom, one of which is polar and one of which is nonpolar.
What is the formula for an ionic compound containing Ba²⁺ ions and Cl⁻ ions? A. BaCl B. Ba2Cl C. BaCl2 D. BaCl3 E. Ba3Cl
C. BaCl2 Two ions of chlorine are needed to balance out the positive charge on the barium ion
Consider the fourth period elements Ca, Mn, Co, Se, and Kr. Which of these atoms are paramagnetic? A) Ca, Mn, Co B) Mn, Co, Kr C) Ca, Kr, Se D) Mn, Co, Se E) Ca, Kr
D) Mn, Co, Se A paramagnetic element is one whose electron configuration contains any unpaired electrons, so they are those elements that are not at the right-hand edge of a given block (s, p, d, f) of the periodic table. Of these options, Kr and Ca are at the right-hand edges of the p and s block, respectively; the species Mn, Co, and Se are not at the edge of their blocks, and therefore have unpaired electrons and are paramagnetic.
Iron forms compounds as both a ferrous Fe(II) and a ferric Fe(III) ion. These two ions differ by: A. 1 proton B. 1 neutron C. 2 protons D. 2 electrons E. 1 electron
E. 1 electron A ferrous (Fe²⁺) ion has one more electron than a ferric (Fe³⁺) ion.
Write the formula for hydroiodic acid
HI
Complete the MO diagram (below) to determine if NO is paramagnetic or diamagnetic.
NO is paramagnetic NO has 11 electrons in the valence shell. This means that there is an unpaired electron in a π* antibonding orbital.
Write the chemical formula for sodium sulfate decahydrate
Na2SO4 . 10 H2O
Complete the MO diagram (below) to determine if OF⁻ is paramagnetic or diamagnetic.
OF⁻ is diamagnetic. OF⁻ has 14 electrons in the valence shell. There are no unpaired electrons in this ion.
Write the chemical formula for tetraphosphorus hexasulfide
P4S6
Write the chemical formula for strontium bromide
SrBr₂
What is the correct IUPAC name for Ca(NO₃)₂?
calcium nitrate
Draw the Lewis structure for sulfite (SO₃²⁻) with minimized formal charges. Does this molecule exhibit resonance?
image 14 yes resonance
Chloroform (CHCl₃) is an important laboratory solvent with a relatively high vapor pressure at room temperature. Draw the Lewis structure of CHCl₃ and then determine the ideal bonding angle(s) for the Cl-C-Cl bond(s). A. 90 B. 109.5 C. 120 D. 180
image 16 B. 109.5
Draw the Lewis structure of ICl₄⁻ and then determine its electron domain and molecular geometries.
image 17 electron domain= octahedral molecular geometries= square planar
Draw the Lewis structure of AsF₅ and then determine the ideal bonding angle(s) of the central atom.
image 18 90 and 120
Draw the Lewis structure of SO₂ (with minimized formal charges) and then determine the ideal bonding angle(s) of the central atom.
image 19 120
Draw the Lewis structure of HCN and then determine its electron domain and molecular geometries.
image 20 linear/linear
Draw the Lewis structure of O₂ and then determine if the molecule is polar or nonpolar.
image 30 nonpolar
Draw the Lewis structure of CH₃NCO and then choose the appropriate set of hybridization states for the three central atoms. Your answer choice is independent of the orientation of your drawn structure.
image 39 sp³ / sp² / sp
What is the correct IUPAC name for HClO₄(aq)?
perchloric acid
Identify the LUMO in the MO diagram of NO (shown below). (image 44)
π* (2px or 2py). The LUMO is the lowest energy (y-axis of the diagram) that does NOT contain electrons.
Identify the LUMO in the MO diagram of C₂ (shown below). (image 43)
σ (2pz orbitals). The LUMO is the lowest energy (y-axis of the diagram) that does NOT contain electrons.
How many moles of CH₃OH are there in 150.0 mL of 0.210 M CH₃OH?
0.0315 mol
What is the molarity of a solution that contains 0.180 moles KOH in 0.350 L of solution?
0.514 M
A solution is made using 65.1 g of hexane (MM = 86.18 g/mol) and 60.0 g of octane (MM = 114.2 g/mol). What is the mole fraction of the hexane in the solution?
0.590
What is the concentration of sodium ions in 0.300 M Na₂CO₃?
0.600 M
What is the concentration of sodium ions in 0.300 M Na₂SO₄?
0.600 M
Percent by definition is parts per hundred. % (w/w) = (mass of solute/mass of solution) x 100. For very dilute solutions, chemists will often use parts per thousand or parts per million (ppm) or parts per billion (ppb). Calculate the concentration of a solution using each of these units. The legal limit of blood alcohol limit in most states is 0.080 grams per 100.0 grams of blood. What is this concentration in parts per thousand?
0.8 ppt
what volume in L of a 0.32 M Mg(NO3)2 solution contains 45 g of Mg(NO3)2
0.95 L.
The most common ion formed by lithium has a charge of
1
The percent by mass of phenol (MM = 94.11 g/mol) in an aqueous solution is 10.9%. What is the molality of the phenol solution?
1.30 m
For each of the following antibiotics, determine how many moles of each compound are present for the given mass. How many moles of tinidazole (C₈H₁₃N₃O₄S) are in 354.3 grams?
1.433 mol
The compound PSI₃ is called phosphorothioic triiodide. P has 5 valence electrons, S has 6 valence electrons, and I has 7 valence electrons. What is the total number of valence electrons in the molecule?
32
An aqueous solution of acetone (MM = 58.08 g/mol) has a molality of 4.45 m and a density of 1.25 g/mL. What is the molarity of acetone in the solution?
4.42 M
Percent by definition is parts per hundred. % (w/w) = (mass of solute/mass of solution) x 100. For very dilute solutions, chemists will often use parts per thousand or parts per million (ppm) or parts per billion (ppb). Calculate the concentration of a solution using each of these units. The legal limit of blood alcohol limit in most states is 0.080 grams per 100.0 grams of blood. What is this concentration in parts per billion?
800000 ppb
What is the percent by weight (w/w%) of sugar in soda? Assume the average mass of sugar in soda is 35 g and the total mass is 370 g.
9.5%
Water is a polar molecule because A) water is a bent molecule and oxygen is more electronegative than hydrogen. B) oxygen is a nonmetal and hydrogen is a metal. C) the hydrogen atoms only have one electron each while the oxygen atom has 8 electrons. D) water is an ionic compound.
A) water is a bent molecule and oxygen is more electronegative than hydrogen. Water is a polar molecule because it is a bent molecule that has an oxygen atom that is more electronegative than hydrogen.
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 diatomic molecule has the largest dipole moment? A) HF B) HCl C) HBr D) HI
A. HF A dipole moment is a separation of charge within a molecule. A dipole moment occurs due to difference in electronegativity between the bonded atoms. Greater differences in electronegativity lead to a larger dipole moment. In this case, the differences in electronegativity values between hydrogen and fluorine is the greatest. Therefore, HF will have the largest dipole moment.
Choose the structure that has the formal charge correctly assigned. (image I) A. I B. II C. III D. IV
A. I I. Formal charge can be calculated using the following equation: formal charge = [# of valence electrons] - [electrons in lone pairs + 1/2 the number of bonding electrons]. For aniline anion, the nitrogen has 5 valence electrons, 4 electrons in lone pairs and 4 bonding electrons, therefore the formal charge = 5-[4+1/2(4)] = -1.
Xenon is a noble gas that is capable of forming compounds. One of these compounds is XeBr₂Cl₂. If the molecule has a octahedral geometry and only 4 bonding domains, what is the molecular geometry (shape) for XeBr₂Cl₂? A) square planar (X-shape) B) square pyramidal C) octahedral D) T-shape
A. Square planar (x shape) According to VSEPR, a molecule which has 6 electron domains and 4 bonding domains has a square planar or X-shape.
Determine the correct formula for aluminum oxide.
Al₂O₃ Aluminum forms ions that have a +3 charge and oxygen forms ions that have -2 charge. It would take two aluminum ions to balance the charge of three oxygen ions. This is the lowest number of each ion to reach a neutral formula unit.
Predict the chemical formula for the ionic compound formed by the elements Ba and S
BaS
Which ion will be attracted to a magnetic field? A) C²⁺ B) O²⁻ C) F⁺ D) Be E) All of the above
C) F⁺ Only paramagnetic atoms are attracted to magnetic fields, so you need to determine which of these options is not diamagnetic. Ions are attracted to magnetic fields when they are paramagnetic (when their electron configurations contain any unpaired electrons). Of these options, F⁺ has the electron configuration [He]2s²2p⁴, which has unpaired electrons in the 2p orbital. Therefore, F⁺ will be paramagnetic and therefore attracted to a magnetic field.
Which of the following compounds does NOT exhibit covalent bonding? A. CO2 B. CO C. CoCl2 D. HCOOH E. Na2CO3
C. CoCl2 Covalent bonds occur between two nonmetals. CoCl₂ contains a metal and a nonmetal ion. These ions are held together by ionic bonding.
Which of the following molecules is considered least stable according to molecular orbital theory? A) H₂⁻ B) H₂ C) He₂ D) He₂⁺
C. He2 Draw the MO diagram for each molecule and think about the number of bonding and antibonding electrons. High bond orders indicate high stability. He₂ is the least stable.
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 Carbon dioxide is a molecular compound composed of two oxygen atoms with covalent double bonds to a central carbon atom. Both C and O are to the right of the "staircase" on the periodic table, as nonmetals.
Xenon is a noble gas that is capable of forming compounds. One of these compounds is XeBr₂Cl₂. The molecule has 6 electron domains. What is the electron domain geometry for XeBr₂Cl₂? A) square planar (X-shape) B) tetrahedral C) octahedral D) trigonal bipyramidal
C. octahedral According to VSEPR, a molecule which has 6 electron domains has an octahedral geometry.
Write the chemical formula for chromium(III) sulfide
Cr2S3
Where are the π electrons delocalized in a benzene (C₆H₆) molecule? A) They are delocalized between the carbons in the plane of the ring. B) They are delocalized between the carbons and above the plane of the ring. C) They are delocalized between the carbons and below the plane of the ring. D) They are delocalized above and below the plane of the ring.
D) They are delocalized above and below the plane of the ring. The π electrons are delocalized above and below the plane of the ring.
Choose the structure that has the formal charge correctly assigned. (image III) A. I B. II C. III D. IV
D. IV IV. Formal charge can be calculated using the following equation: formal charge = [# of valence electrons] - [electrons in lone pairs + 1/2 the number of bonding electrons]. In protonated methanol, oxygen has 6 valence electrons, 2 electrons in lone pairs and 6 bonding electrons, therefore the formal charge = 6-[2+1/2(6)] = +1.
Which diatomic molecule has the smallest dipole moment? A) F₂ B) O₂ C) N₂ D) H₂ E) All equal
E. all equal Homonuclear molecules do not have charge separation between the identical nuclei and therefore contain no dipole moments.
Which structures below are plausible resonance contributors for NCNH⁻? Assume the connectivity is as written. (image 11)
I and III. Structures I and III are are both plausible resonance contributors for NCNH⁻. In a resonance structure, pi electrons and non-bonding electrons can be placed in different locations, but the electrons in sigma bonds must remain the same.
Which structures below are plausible resonance contributors for OOO? Assume the connectivity is as written. (image 12)
II and III. Structures II and III are are both plausible resonance contributors for OOO. In a resonance structure, pi electrons and non-bonding electrons can be placed in different locations, but the electrons in sigma bonds must remain the same. Period II atoms want an octet, but they cannot exceed an octet.
Predict the chemical formula for the ionic compound formed by the elements Sr and Cl
SrCl2
What is the correct IUPAC name for CaCl₂ · 2H₂O?
calcium chloride dihydrate
Draw the Lewis structure for thiosulfate (S₂O₃²⁻) with minimized formal changes. How many TOTAL likely resonance structures exist for S₂O₃²⁻? Hint: In this case, it is more stable (preferred) to place a negative charge on the larger atom.
image 15 3 resonance structure
Draw the Lewis structure of Br₃⁻ and then determine its electron domain and molecular geometries.
image 21 trigonal bipyramidal/linear
Draw the Lewis structure of IF₅ and then determine its electron domain and molecular geometries.
image 22 octahedral / square pyramidal
Draw the Lewis structure of water (H₂O) and then determine its electron domain and molecular geometries.
image 23 tetrahedral / bent (109.5º)
Draw the Lewis structure of urea ((NH₂)₂CO) and then determine if the molecule is polar or nonpolar.
image 31 polar
Xenon is a noble gas that is capable of forming compounds. One of these compounds is XeBr₂Cl₂. XeBr₂Cl₂ has 36 total valence electrons. Draw the correct Lewis structure for XeBr₂Cl₂ that minimizes the formal charges on all atoms.
image 32
The compound PSI₃ is called phosphorothioic triiodide. PSI₃ has 32 total valence electrons. Draw the Lewis structure for PSI₃ following the octet rule.
image 33
The compound PSI₃ is called phosphorothioic triiodide. The formal charge of P is 1 and the formal charge of S is -1. Draw the correct Lewis structure for PSI₃ that minimizes the formal charges on all atoms.
image 34
Draw the Lewis structure of acetic acid (CH₃COOH) and then choose the appropriate set hybridization states for the three central atoms. Your answer choice is independent of the orientation of your drawn structure.
image 38 sp³ / sp² / sp³
A Lewis structure for N₃⁻ is shown below, however, its formal charges are not minimized. Starting from this structure, complete the correct structure with minimized formal charges.
image 7
A skeletal structure for for AsO₃³⁻ is shown below. Starting from this structure, complete the Lewis structure that follows the octet rule on all atoms.
image 8
