CHEM 1331 Exam 2 Chp 3,4,5 Quiz Questions
Which is the correct order of decreasing bond polarity? A.F-F > F-O > F-C B.F-C > F-F > F-O C.F-C > F-O > F-F D.F-O > F-C > F-F E.F-O > F-F > F-C
C. F-C > F-O > F-F
Which is the correct order of decreasing bond polarity? A. F-F > F-O > F-C B. F-C > F-F > F-O C. F-C > F-O > F-F D. F-O > F-C > F-F E. F-O > F-F > F-C
C. F-C > F-O > F-F
Which of the following elements, when combined with fluorine, would produce the most ionic bond? A.Ge B.Ru C.K D.N E.Mg
C. K
Which of the following has the bonds listed in the order of increasing bond energy? A.N≡N, N = N, N − N B.N≡N, N − N, N = N C.N − N, N = N, N≡N D.N = N, N − N, N≡N E.N = N, N≡N, N − N
C. N − N, N = N, N≡N
Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H and 53.3 % O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound? A.C4H8O6 B.C5H10O5 C.C5H12O5 D.C6H12O4 E.None of these choices is correct.
B. C5H10O5
A certain compound has the percent composition (by mass) 85.63% C and 14.37% H. The molar mass of the compound is 42.0 g/mol. Calculate the empirical formula and the molecular formula. A.CH3 and C3H6 B.CH2 and C3H6 C.CH3 and C2H6 D.C2H6 and C3H9 E.C2H3 and C4H6
B. CH2 and C3H6
Which ion is planar? A.NH4+ B.CO32- C.SO32- D.ClO3- E.all the polyatomic ions given are planar
B. CO32-
Predict the product formed when calcium, Ca, combines with arsenic, As? A.Ca2As3 B.Ca3As2 C.CaAs D.CaAs2 E.Ca2As
B. Ca3As2
Pick the ion in each set with the smallest radius. i) O2-, F -, N3- ii) Na+, Mg2+, F - iii)Cr2+, Cr3+ A.F -, Na+, Cr2+ B.F -, Mg2+, Cr3+ C.N3-, Mg2+, Cr3+ D.O2-, Na+, Cr2+ E.N3-, F -, Cr2+
B. F -, Mg2+, Cr3+
Phosphoric acid can be prepared by reaction of sulfuric acid with "phosphate rock" according to the equation: Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4 Suppose the reaction is carried out starting with 125 g of Ca3(PO4)2 and 75.0 g of H2SO4. Which substance is the limiting reactant? A.Ca3(PO4)2 B.H2SO4 C.CaSO4 D.H3PO4 E.none of these
B. H2SO4
In which of the following compounds does the bond between the central atom and bromine have the greatest ionic character? A.LiBr B.KBr C.SeBr2 D.AsBr3 E.CaBr2
B. KBr
Balanced chemical equations imply which of the following? A.Numbers of molecules are conserved in chemical change. B.Numbers of atoms are conserved in chemical change. C.Volume is conserved in chemical change. D.A and B E.B and C
B. Numbers of atoms are conserved in chemical change.
Rank the members of this set of compounds in order of decreasing ionic character of their bonds. Use partial charges to indicate the bond polarity of each bond.PCl3, PBr3, PF3 A. P-Cl > P-F > P-Brδ+ δ- δ+ δ- δ+ δ- B. P-F > P-Cl > P-Brδ+ δ- δ+ δ- δ+ δ- C. P-Br > P-Cl > P-Fδ- δ+ δ- δ+ δ- δ+ D. P-F > P-Br > P-Clδ+ δ- δ+ δ- δ+ δ- E.none of these
B. P-F > P-Cl > P-Brδ+ δ- δ+ δ- δ+ δ-
Which of the following has a zero dipole moment? A.NO2 B.PF5 C.HCN D.NH3 E.SO2
B. PF5 A. NO2 > Has 1 lone e- > uneven/asymmetrical C. HCN > dipole moment going to the right towards N. D. NH3 > dipole moment going in towards N E. SO2 > Lone pair pulls it upwards
Which of the following has primarily ionic bonding? A.N2O3 B.Rb2O C.CO2 D.CCl4 E.none of these
B. Rb2O
Phosphorus, P4, can be prepared from calcium phosphate by the reaction mass: 3270 g.......1770 g....690 g molar mass: 310 g/mol, 60.1 g/mol, 12.0 g/mol 2Ca 3(PO 4) 2 + 6SiO 2 +10C→ 6CaSiO 3 + P 4 + 10CO The molar mass for each reactant is shown below the reactant, and the mass of each reactant for this problem is given above. Which reactant is the limiting reagent? A.C B.SiO2 C.P4 D.Ca3(PO4)2 E.More information is needed.
B. SiO2
Metals react with oxygen gas to produce oxides with the general formula MxOy. Write a balanced chemical equation for the reaction of titanium with oxygen to yield titanium(IV) oxide. A.4 Ti(s) + O2(g) → 2 Ti2O(s) B.Ti(s) + O2(g) → TiO2(s) C.2 Ti(s) + O2(g) → 2 TiO(s) D.Ti(s) + O(g) → TiO(s) E.8 Ti(s) + O2(g) → 2 Ti4O(s)
B. Ti(s) + O2(g) → TiO2(s) Titanium (IV)= the charge, so the charge is 4. O has a -2 charge, to balance the +4 change of Ti, we need 2 molecules of O. So our final product is TiO2, and then we can check if it's balanced.
After an atom has lost an electron it becomes a/an ______ and has a _______ charge. A.anion, positive B.cation, positive C.anion, negative D.cation, negative E.nucleus, positive
B. cation, positive
In balancing an equation, we change the __________ to make the number of atoms on each side of the equation balance. A.formulas of compounds in the reactants B.coefficients of compounds C.formulas of compounds in the products D.subscripts of compounds E.none of these
B. coefficients of compounds
The hybridization of the central atom in XeF5+ is: A.dsp3 B.d2sp3 C.sp D.sp3 E.sp2
B. d2sp3 Determine the valence electrons, here we have 42. Subtract the highest multiple of 8 from 42 to find the # of lone electrons. So we'll have 42-40= 2 lone e- on Xe. So we have 6 domains=d2sp3
The hybridization of Br in BrF3 is A.sp3 B.dsp3 C.d2sp3 D.sp E.sp2
B. dsp3
According to Pauling's scale, what are the two most electronegative elements? A.cesium and francium B.fluorine and oxygen C.fluorine and cesium D.xenon and radon E.hydrogen and helium
B. fluorine and oxygen
Consider a specific chemical reaction represented by the equation aA + bB → cC + dD. In this equation the letters A, B, C, and D represent chemicals, and the letters a, b, c, and d represent coefficients in the balanced equation.How many possible values are there for the quantity "c"? A.3 B.infinite C.2 D.1 E.4
B. infinite
What is the name of the acid formed when HClO4 liquid is dissolved in water? A.hydrochloric acid B.perchloric acid C.chloric acid D.chlorous acid E.hydrochlorate acid
B. perchloric acid
Which of the following has a bond order of 1.5? A.O2+ B.N2 C.O2- D.C2 E.none of these
C. O2- *Know difference and how to fill out heteronuclear and homonuclear diatomic molecules https://youtu.be/MLA_RVTFt1M Bond order: (Bonding orbitals-antibonding orbitals)/2 A. 2.5 B. 3 D. 2
Which of the following species is best described by drawing resonance structures? A. PH3 B. NH4+ C. O3 D. SO3 E. HCN
C. O3
Which of the following compounds will contain the bonds with the largest % ionic character? A.H2O B.LiI C.RbF D.CaO E.HCl
C. RbF
Which of the following compounds will contain the bonds with the largest % ionic character? A.H2O B.LiI C.RbF D.CaO E.HCl
C. RbF
A chloride of silicon contains 79.1 mass % Cl. What is the empirical formula of the chloride? A.SiCl B.SiCl2 C.SiCl3 D.SiCl4 E.Si3Cl
C. SiCl3
The hybridization of I in IF4- is A.sp3 B.sp C.d2sp3 D.dsp3 E.sp2
C. d2sp3
For which compound does 0.256 mole weigh 12.8 g? A.C2H4O B.CO2 C.CH3Cl D.C2H6 E.none of these
C. CH3Cl Find the grams of each compound and convert 0.256 moles to grams using the weight of each compound. C. (0.256 mols) * (50 g/ 1 mol)= 12.8 g
Calcium reacts with oxygen to make calcium oxide, CaO. What is the theoretical yield (g) of CaO(s) that could be prepared from 7.66 g of Ca(s) and 2.17 g of O2(g)? Enter your answer with two decimal places.
7.61 ± 1% I initially entered, 7.59
The following two reactions are important in the blast furnace production of iron metal from iron ore (Fe2O3): 2C+O2 > CO2 F2O3 + 3CO > 2Fe + 3CO2 Using these balanced reactions, how many moles of O2 are required for the production of 5.35 kg of Fe?
71.8 moles
Calcium reacts with oxygen to make calcium oxide, CaO. What is the theoretical yield (g) of CaO(s) that could be prepared from 8.85 g of Ca(s) and 2.33 g of O2(g)? Enter your answer with two decimal places.
8.17 ± 1%
Aluminum and oxygen react according to the following equation: 4Al(s) +3O2(g) => 2Al2O3(s) What mass of Al2O3, in grams, can be made by reacting 4.6 g Al with excess oxygen?
8.7
What is the mass (in g) of 2.435 mol of H2S?
82.98 ± 2% mol>grams 2.435 mol * (34 g/ 1 mol)= 82.8 g
What is the formula mass of the hypothetical compound A2R1Q1 if the atomic masses of A, R and Q are 21.8, 14.2 and 31.9, respectively? Enter your answer with one decimal place and do not enter units.
89.7 ± 2%
Calculate the mass in grams of 33.64 mol of Na 2HPO 4*7H 2O.
9,018 ± 2% *Made sure you add the 7H2O, total mass= 268 g
What is the percent yield of PI3, if 58.62 g of I2 are reacted with an excess of phosphorus according to the following equation and 60.75 g are actually obtained? 2 P(s) + 3 I2(s) ---> 2PI3(s)
95.8 %
Calculate the energy change for the reaction below, N2 + 3F2 > 2NF3 Bond, Bond Energy N-N, 163 N=N, 418 N- triple bond -N, 945 F-F, 155 N-F, 283 A.-288 kJ B.-1070 kJ C.-637 kJ D.+288 kJ E.+293 kJ
A. -288 kJ
What are the empirical formulas of a) ethylene glycol, a radiator antifreeze, molecular formula C2H6O2 b) peroxodisulfuric acid, a compound used in bleaching agents, molecular formula H2S2O8 A.C2H6O2, H2S2O8 B.C2H3O2, H2S2O4 C.CH3O, HSO4 D.CH3O2, HSO4 E.CH3O, HSO6
C. CH3O, HSO4
Fluorite, a mineral of calcium, is a compound of the metal with fluorine. Analysis shows that a 2.76g sample of Fluoritecontains 1.42g calcium. Calculate the mass fraction of calciumand fluorine in Fluorite. A.0.514 Ca, 0.486 F B.0.486 Ca, 0.514 F C.51.4% Ca 48.6% F D.48.6% Ca 51,4% F E.1.42 Ca 1.34 F
A. 0.514 Ca, 0.486 F
Which of the following has the bonds ordered from weakest to strongest? A.Si − Cl, Si − I, Si − F, Si − Br B.Si − Br, Si − Cl, Si − F, Si − I C.Si − F, Si − Cl, Si − Br, Si − I D.Si − I, Si − Br, Si − Cl, Si − F E.Si − I, Si − Cl, Si − Br, Si − F
D. Si − I, Si − Br, Si − Cl, Si − F
How many unpaired electrons in the F22+ ion are based on molecular orbital theory? The order of the molecular orbitals are (σ2s)(σ*2s)(σ2p)(π2p)(π*2p)(σ*2p). A.4 B.1 C.0 D.2 E.3
D. The bond order is 2
In thionyl chloride, Cl2SO (S is the central atom), the formal charge on oxygen and number of lone pairs on oxygen are, respectively, (assume all the atoms obey the octet rule) A.+1 and one B.-1 and one C.0 and none D.+2 and one E.-1 and three F.none of these answers is correct
E. -1 and three
The rusting of iron is represented by the equation4Fe + 3O2 → 2Fe2O3.If you have a 1.34-mol sample of iron, how many moles of Fe2O3 will there be after the iron has rusted completely? A.1.34 mol B.2.01 mol C.0.447 mol D.0.89 mol E.0.670 mol
E. 0.670 mol
Determine the coefficient for O2 when the following equation is balanced in standard form (smallest whole numbers). C6H14(g) + O2(g) → CO2(g) + H2O(g) A.12 B.6 C.13 D.14 E.19
E. 19
Copper(l) sulfide can react with oxygen to produce copper metal by the reaction Cu2S + O2 => 2Cu + SO2. If 5.00 g of Cu2S is used, then what is the theoretical yield of Cu? A.10.0 g B.1.99 g C.1.00 g D.5.00 g E.3.99 g
E. 3.99 g
What is the number of oxygen atoms in 55.0 g of iron(II) hydroxide (Fe(OH)2 (molar mass 89.85 g/mole))? A.0.612 B.1.22 C.2.00 D.3.69 x 1023 E.7.37 x 1023
E. 7.37 x 1023 Fe grams > mols> mole ratio of O in the compound > atoms of O. (55g Fe(OH2)) * (1 mol/ 89.85 g Fe (OH2)) * (2 mol O/1 mol Fe (OH)2) * (6.022*10^23/ 1 mol)= 7.37 * 10^23
What is the percent yield of PI3, if 58.62 g of I2 are reacted with an excess of phosphorus according to the following equation and 60.75 g are actually obtained? 2 P(s) + 3 I2(s) ---> 2PI3(s) A.84.97 % B.1.57 % C.48.37 % D.37.6 % E.95.8 %
E. 95.8 %
Select the correct formula for a compound formed from barium and nitrogen. A.BaN B.BaN2 C.Ba2N3 D.Ba2N E.Ba3N2
E. Ba3N2
A gaseous hydrocarbon was analyzed and found to consist of 83.65% carbon by mass. The molar mass of the compound is 86.2 g/mol. What is the molecular formula of the compound? A.CH2 B.C2H4 C.C3H7 D.C18H21 E.C6H14
E. C6H14
A certain compound has the percent composition (by mass) 85.63% C and 14.37% H. The molar mass of the compound is 42.0 g/mol. Calculate the empirical formula and the molecular formula. A.C2H6 and C3H9 B.CH3 and C2H6 C.C2H3 and C4H6 D.CH3 and C3H6 E.CH2 and C3H6
E. CH2 and C3H6
Which of the following has the largest radius? A.Na B.Cl - C.Rb + D.Sr E.Cs
E. Cs
Which of the following bonds is weakest? A.P-P B.P-F C.P-Cl D.P-Br E.P-I
E. P-I
Which has sp3d hybridization and no dipole moment? A.PCl3 B.BF3 C.SF4 D.BrF3 E.PCl5
E. PCl5 Dipole moments usually occur in polar molecules and molecules like N, O, & F bonded to H. A. PCl3- sp2, polar=dipole moment B. BF3- sp2, nonpolar C. SF4- sp3, polar D. BrF3- sp2, polar How to solve; determine hybridization, then to determine polarity figure out general shape by finding the lone pairs. To find # of lone pairs, find valence e- by looking at the group number and adding them all up. Subtract the highest multiple of 8 from the # of valence e- to determine lone electrons. Anything left over will change the shape. So SF4 seems like it would be non-polar, but because of there are lone pairs it makes the whole shape asymmetrical and the density heavier on one side thus creating that dipole moment. Same with BrF3, where it has 4 lone electrons and creates a dipole moments with- asymmetrical shape= the unequal distribution of charge. If it was CH4 or BF3 where we have no lone pairs, equal distribution of charge in an symmetrical shape it would be non-polar=no dipole moment. The star shape in PCl5 is also an equal distribution so there is no dipole moment.
Whenever a set of equivalent tetrahedral atomic orbitals is required, an atom will adopt a set of sp3 orbitals. True False
True
A metal oxide with the formula M2O contains 11.18% oxygen by mass. In the box below, type the symbol for the element represented by M.
Cu
In the reaction of aluminum metal and oxygen gas to make aluminum oxide, how many moles of aluminum will react with 0.80 grams O2? A.1.0 B.19 C.0.067 D.0.033 E.0.10
D. 0.033
A 7.04-g sample of potassium chlorate was decomposed according to the following equation: 2KClO3 → 2KCl + 3O2How many moles of oxygen are formed? A.2.76 g B.0.0574 mol C.0.0383 mol D.0.0862 mol E.none of these
D. 0.0862 mol
A 7.04-g sample of potassium chlorate was decomposed according to the following equation: 2KClO3 → 2KCl + 3O2How many moles of oxygen are formed? A.2.76 g B.0.0574 mol C.0.0383 mol D.0.0862 mol E.none of these
D. 0.0862 mol
Calculate the mass, in grams, of 7.35 mol water. A.10.7 B.0.408 C.25.4 D.132 E.18.0
D. 132
Hydrogen chloride can be prepared by the reaction shown below: 2NaCl(s) + H2SO4(l) => 2HCl(g) + Na2SO4(s) How many grams of HCl can be prepared from 393 g H2SO4 and 4.00 moles NaCl? A.293 g B.1.003 g C.786 g D.146 g E.393 g
D. 146 g
How many grams of Ca(NO3)2 can be produced by reacting excess HNO3 with 9.69 g of Ca(OH)2? A.42.9 g B.10.73 g C.19.4 g D.21.5 g E.9.69 g
D. 21.5 g Our balanced equation is (double displacement, we can tell cause calcium has switched) Ca(OH)2 + 2HNO3 > Ca(NO3)2 + 2H2O 9.69g Ca(OH)2 * (1 mol/74 g) * (1 mol Ca(NO3)2/ 1 mol Ca(OH)2) * (164 g Ca(NO3)2/ 1 mol)= 21.5g of Ca(NO3)2.
Fe2O3 (molar mass = 159.7 g/mol) reacts with CO (molar mass = 28.0 g/mol) according to the equationFe2O3 + CO --> Fe + CO2 (unbalanced)When 145.7 g of CO reacts with excess Fe2O3, how many moles of Fe (iron) will be produced? A.2.60 mol Fe B.10.4 mol Fe C.7.80 mol Fe D.3.47 mol Fe E.1.73 mol Fe
D. 3.47 mol Fe
Calculate the mass, in grams, of 1.0 mol of oxygen gas. A.1.0 B.16 C.12 D.32 E.28
D. 32
A certain metal, M, has four stable isotopes: 50M (4.31%, 49.95 amu), 52M (83.76%, 51.94 amu), 53M (9.55%, 52.94 amu) and 54M (2.38%, 53.94 amu). What is the average atomic mass of the metal as it would be seen in the periodic table? A.51.87 amu B.52.67 amu C.52.24 amu D.52.01 amu E.52.31 amu
D. 52.01 amu
A given sample of a xenon fluoride compound contains molecules of a single type XeFn, where n is some whole number. Given that 8.11 × 1020 molecules of XeFn weigh 0.330 g, calculate n. A.3 B.4 C.2 D.6 E.1
D. 6
Balance the following equation with the smallest set of whole numbers.C4H10 + O2 => CO2 + H2OWhat is the coefficient for CO2 in the balanced equation? A.1 B.4 C.6 D.8 E.12
D. 8
How many oxygen atoms are there in one formula unit of Ca3(PO4)2? A.2 B.4 C.6 D.8 E.none of these
D. 8
Combustion analysis of a hydrocarbon produces 0.396 g of CO2 and 0.163 g of H2O.Which of the following molecular formulas is consistent with the analysis? A.CH4 B.C2H6 C.C2H2 D.C2H4 E.C3H8
D. C2H4 We need to find moles of the elements away from the compound for all of them. 1) .396 g CO2 * (1 mol/44g)* (1 mol C/ 1 mol CO2)= .009 mol C 2) 0.163 g H2O * (1 mol/18g) * (2 mol H/ 1 mol H2O)= 0.018 mol H 3) Convert each to grams, then add them together and subtract it from the compounds total mass. .009 mol C= .108 g C 0.018 mol H= .018 g H Total compound mass: 0.396 g CO2 + 0.163 g H2O= .559 g .559-.108-.018= .433 g O Convert to mols .433 g O * (1 mol/16g O)= .027 mol O Now find the ratio of each by dividing each by smallest ratio (similar how you would find empirical formula). .009 mol C/ .009= 1 C 0.018 mol H/ .009= 2 H .027 mol O/ .009= 3 O Empirical= CH2, match it with the more exact and expanded form- molecular formula with the same ratio> C2H4
Consider the molecular orbital energy level diagrams for O2 and NO. Which of the following is true? I.Both molecules are paramagnetic. II.The bond strength of O 2 is greater than the bond strength of NO. III.NO is an example of a homonuclear diatomic molecule. IV.The ionization energy of NO is smaller than the ionization energy of NO +. A.I only B.II and III C.I and II D.I and IV E.I, II, and IV
D. I and IV I. O2=12 & NO=11, 4e- fill up the 2s orbitals, leaving 8 e- in O2 and 7e- in NO to fill up the 2p orbitals. Draw it out if you're unsure, but starting at 2p (pi &/or sigma) fill it out. https://youtu.be/-A5Y-eZHTQE
Which of the following orders of electronegativity is incorrect? A.Si < P < N B.Se < S < O C.I < Cl < F D.N < P < S E.Si < N < O
D. N < P < S
Assuming that it has the order of MO energies shown, which of the following electron distributions among the molecular orbitals best describes the NO molecule? σ2s σ2s* π2py=π2px σ2pz π2py*=π2px* σ2pz* A. 2, 2, 4, 1, 3, 0 B. 2, 2, 4, 2, 4, 1 C. 2, 2, 4, 2, 1, 0 D. 2, 2, 4, 2, 2, 0 E. 2, 2, 4, 2, 4, 2
C. 2, 2, 4, 2, 1, 0
If a molecule demonstrates paramagnetism, then : I. The substance can have both paired and unpaired electrons. II. The bond order is not a whole number. III. It can be determined by drawing a Lewis structure. IV. It must be an ion. A. I, II B. I, II, IV C. II, III D. I only E. All of the above are correct.
D. I only
Calculate the formula mass of sodium carbonate. A.51.0 B.60.0 C.66.99 D.82.99 E.105.99
E. 105.99 *Recall the charges of common polyatomic ions Na=+1 CO3= -2 Balance the 2 to get the formula Na2CO3
How many hydrogen atoms are present in 42 g of ammonium carbonate? A.3.5 B.8 C.2.6 x 1023 D.1.1 x 1024 E.2.1 x 1024
E. 2.1 x 1024
How many atoms of H are there in 4.9 g H2O? A.9.0 x 10-25 B.3.0 x 1024 C.1.1 x 1026 D.5.4 x 10-1 E.3.3 x 1023
E. 3.3 x 1023
Hydrocortisone valerate is an ingredient in hydrocortisone cream, prescribed for skin problems. Its molecular formula is C26H38O6. What is the percent by mass of carbon in hydrocortisone valerate? A.60.1% B.76.9% C.54.2% D.43.6% E.69.9%
E. 69.9%
What is the theoretical yield of bismuth when 239.5 g of Bi2O3 reacts with excess carbon as shown below?E. The theoretical yield of HCl is 2.0 moles. Bi2O3 + C(s) => Bi(s) + CO(g) (not balanced)
214.8 ± 2%
Calculate the number of chlorine atoms present in 10.15 g of chloroform, CHCl3. When you have the answer, determine its log (base 10) and enter its value with three decimal places and no units.
23.187 ± 0.05 solve for # mols of Cl using mol ratio of Cl atoms in CHCl3. (10.15g CHCl3) * (1 mol/ 118 g) * (3 mol Cl/ 1 mol CHCl3)= .258 mol Cl Convert to atoms .258 mol Cl * (6.022 * 10^23/ 1 mol)= 1.55 * 10^23 > log (1.55* 10 ^23)= 23.19
Calculate the number of chlorine atoms present in 39.11 g of chloroform, CHCl3. When you have the answer, determine its log (base 10) and enter its value with three decimal places and no units.
23.772 ± 0.05
What is the molecular (formula) mass of a compound with the formulaM2(XO3)2 if the atomic mass of M is 40.2 amu and that of X is 31.3 amu?
239 ± 2%
How many molecules are contained in 4.84 moles of H2O? Once you have the answer, determine the log (base 10) of it and enter that value with three decimal places into the answer box. Do not add units.
24.465 ± 2% 4.84 mol H2O *(6.022 * 10^23/ 1 mol)= 2.91 * 10^24= log> 24.46 molecules of H2O
The first step in the Ostwald process for making nitric acid is the formation of NO as follows:4NH3 + 5O2 => 4NO + 6H2O According to the equation, 5 moles of NH3 will react stoichiometrically with ________ moles of O2 to form _______ moles of NO.
25/4, 5
When the following equation is balanced, what is the coefficient of B2O3? B5H9(l) + O2(g) => B2O3(s) + H2O(g)
5
In the reaction of N2 and H2 to produce NH3, how many moles of H2 will produce 63.6 grams NH3 if sufficient N2 is present?
5.60 ± 1%
The ethyl alcohol in "gasohol" burns to form CO 2 and H 2O.If the combustion reaction consumes 9.464 moles of C 2H 5OH reacting with excess O 2, how many grams of H 2O are formed?
511.6 ± 1%
When the equation C8H18 + O2 → CO2 + H2O is balanced with the smallest set of integers, the sum of the coefficients is
61
A 5.95-g sample of AgNO3 is reacted with BaCl2 according to the equation 2AgNO3(aq) + BaCl2(aq) → 2AgCl(s) + Ba(NO3)2(aq) to give 3.20 g of AgCl. What is the percent yield of AgCl?
63.7%
A mineral contains only a metal, M, and sulfur. If analysis indicates that a 95.9 g sample of the mineral contains 1.83 g of M, what mass of M (g) is contained in 369 g of the mineral? Enter your answer in decimal format with two decimal places and no units.
7.04 ± 2% You can make a proportion of the old compound=new compound (1.83g/95.9g) = (x/369g) Solve for x (1.83 * 369)/95.9= 7.04g of M
One method for making ethanol, C2H5OH, involves the gas-phase hydration of ethylene, C2H4. Estimate ΔE (kJ) for this reaction from the given average bond dissociation energies in the table below. Enter your answer as the nearest whole number and no units. H2C=CH2 + H2O > H3C-CH2-OH Bond, Kj/mol C=C, 615 C-H, 410 C-C, 350 C-C, 350 O-H, 460
-35 Reactants-products of all bonds broken and formed. (460+615)-(410+350+350)= -35 (O-H + C=C) - (C-H + C-C + C-O) **You broke the double bond, you gotta reconnect it with a single bond. So we have to account for it in our products.
How many grams of H 2O (g) are produced when 2.1 grams O 2 (g) are consumed? C4H6 + O2 > CO2 + H2O
0.64
In the reaction of N2 and H2 to produce NH3, how many moles of N2 will produce 57.2 grams NH3 if sufficient H2 is present N2 + H2= NH3
1.68 ± 1% 57.2g NH3 * (1 mol/ 17g NH3) * (1 mol N2/ 2 mol NH3)= 1.69 mols N2
In the reaction of N2 and H2 to produce NH3, how many moles of N2 will produce 59.4 grams NH3 if sufficient H2 is present? Do not enter units with your answer.
1.74 ± 1%
An ionic compound contains only a metal, M, and bromine. If analysis indicates that a 3.18 g sample of the compound contains 2.05 g of M, what mass of Br in g is contained in 300 g of the mineral? Enter your answer in decimal format with three decimal places and no units.
106.6 ± 2% Solve for x. (1.13 g Br/3.18 g) = (x/300g) (1.13 g Br * 300g)/3.18 g= 106 g Br
Combustion of 3.6812 grams of C4H10 will yield _____ grams of CO2. (Assume 100% yield)
11.150 ± 1% I initially entered, 11.17
A mineral contains only a metal M and fluorine. If analysis indicates that a sample of the mineral contains 1.93 g of M and 1.31 g of F, what mass of fluorine is present in 276 g of the mineral?
111.6 ± 2%
An ionic compound contains only a metal, M, and bromine. If analysis indicates that a 3.8 g sample of the compound contains 2.29 g of M, what mass of Br in g is contained in 374 g of the mineral?Enter your answer in decimal format with three decimal places and no units.
148.6 ± 2%
The reaction between glucose, C6H12O6, and oxygen produces carbon dioxide and water. Write a balanced equation for the reaction and use it to calculate the maximum mass of water that can be produced in a reaction between 1 mol of each reactant.
18 g
In the reaction of N2 and H2 to produce NH3, how many moles of N2 will produce 36.3 moles NH3?
18.1 ± 1%
What is the molecular (formula) mass of a compound with the formulaM2(XO2)2 if the atomic mass of M is 38.2 amu and that of X is 23.5 amu?Do not enter units with your answer.
187 ± 2%
In the reaction of aluminum metal and oxygen gas, aluminum oxide is formed. How many moles of O2 will react with 2.0 moles Al? A.1.5 moles B.1.0 moles C.2.0 moles D.3.0 moles E.6.0 moles
A. 1.5 moles First determine the end product, look at the charges of each and balance them via subscripts. Al has a +3 and O2 has -4 (-2 for each oxygen). We want them to balance out and have opposing equal charges. If we have Al4 and (O2)3 > they would both have +12 and -12 charges respectively. Balance them out: 4Al + 3O2= Al4(O2)3 2.0 mol Al * (3 mol O2/ 3 mol Al)= 1.5 mol O2
What is the mass (in g) of 3.02 mol of H2S? A.103 B.8.86x10-2 C.99.9 D.5.02x10-24 E.1.82x1024
A. 103
How many mmol of iron are there in 650 mg of iron? A.11.6 mmol Fe B.363.02 mmol Fe C.55.85 mmol Fe D.8.95 mmol Fe
A. 11.6 mmol Fe
What is the sum of the coefficients of the following equation when it is balanced using smallest whole numbers? NaNH2 + NaNO3 → NaN3 +NaOH + NH3 A.9 B.7 C.8 D.5 E.6
A. 9
What is the percent yield of the reaction shown below if 31.8 g CO2 are obtained when 21.0 g of CO reacts with 12.8 g of O2? 2CO(g) + O2(g) => 2CO2(g) A.96.4% B.88.7% C.81.2% D.76.1% E.65.0%
A. 96.4%
Which of the following bonds has the lowest percent ionic character? A.C-H B.Na-I C.H-F D.K-F E.Li-Cl
A. C-H
Which of the following has the lowest formal charge on the central atom, the first atom in the formula? (Assume that the electron-dot formula obeys the octet rule.) A.CO32- B.NO3- C.SO3 D.ClO3- E.NH4+
A. CO32-
What is the empirical formula and empirical formula mass for the following compound? gallium(III) sulfate A.Ga2(SO4)3, 427 g/mol B.Ga(SO4)2, 262 g/mol C.Ga(SO4)1.5, 214 g/mol D.Ga2(SO4)3, 363 g/mol E.Ga(SO4)3, 358 g/mol
A. Ga2(SO4)3, 427 g/mol
According to the localized electron model, which of the following statements about the species CN- is false? A.It is paramagnetic. B.The total number of electrons is 14. C.Its bond order is 3. D.It has two pi bonds. E.All of these are true.
A. It is paramagnetic.
A compound with a composition of 87.5 % N and 12.5 % H was recently discovered. What is the empirical formula for this compound? A.NH2 B.N2H3 C.NH D.N2H2 E.N2H
A. NH2 Solve for empirical formula, assume its out of 100g if its not specified. So we have 8735 g N and 12.5gH. 87.5 g N * (1 mol/14g N)= 6.25 mol N 12.5g H * (1 mol/ 1g H)= 12.5 mol H Divide each by the one with the smallest amount of mols N= 6.25/6.25= 1 H= 12.5/6.25= 2 These are the subscripts> NH2
Which of the following molecules has a nonlinear structure? A.O3 B.N2O (central atom is N) C.BeCl2 D.CO2 E.XeF2
A. O3
What hybridization is predicted for the nitrogen atom in the NO3- ion? A.sp2 B.sp3 C.dsp3 D.d2sp3 E.none of these
A. sp2
According to the VSEPR model, the arrangement of electron pairs around NH3 and CH4 is A.the same, because in each case there are the same number of electron pairs around the central atom B.different, because in each case there are a different number of atoms around the central atom C.the same, because both nitrogen and carbon are both in the second period D.different or the same, depending on the conditions leading to maximum repulsion E.different, because in each case there are a different number of electron pairs around the central atom
A. the same, because in each case there are the same number of electron pairs around the central atom
The molecular structure of SOCl2 is A.trigonal pyramidal B.none of these C.octahedral D.trigonal planar E.bent
A. trigonal pyramidal VSEPR Theory electron geometry is tetrahedral C. Octahedral is 6 domains E. Bent is either AX2E2 or AX2E1 A-central atom, X-bonded atoms, E-# of lone pair of electrons. Where the bonded atoms are bent, because the lone pairs take up more space. D. Trigonal planar is AX3 with 3 domains.
How many moles of H 2O (g) are produced when 4.3 grams O 2 (g) are consumed? C4H6 + O2 > CO2 + H2O A.75 B.0.073 C.0.25 D.0.72 E.140
B. 0.073 Balance the equation 2C4H6 + 11O2 > 8CO2 + 6H2O 4.3g O2 * (1 mol/ 32g O2) * (6 mol H2O/ 11 mol O2)= .073 mol H2O
Zinc sulfide is 67.1% zinc by mass. What is the mass fraction of sulfur in zinc sulfide? A.0.671 B.0.329 C.67.1% D.32.9% E.None of these is within 5% of the correct answer
B. 0.329
How many moles of oxygen are produced by decomposing 40.5 g of H2O2 (molar mass = 34.0 g/mol) according to the equation:H2O2 --> H2O + O2 (unbalanced) A.1.191 mol O2 B.0.596 mol O2 C.2.38 mol O2 D.689 mol O2 E.none of these
B. 0.596 mol O2
Caustic soda, NaOH, can be prepared commercially by the reaction of Na2CO3 with slaked lime, Ca(OH)2.How many grams of NaOH can be obtained by treating 1.350 kg of Na2CO3 withCa(OH)2? A.1788.8 g B.101.9 g C.1.79 g D.509.4 g E.1.02 g
B. 10.19 g
Calculate the molecular (formula) mass of the compound: iron(II) acetate tetrahydrate. A.186.9 amu B.245.9 amu C.191.5 amu D.242.7 amu E.197.9 amu
B. 245.9 amu hydrate=H2O tetrahydrate= 4 molecules of H2O
What mass of ammonia, in grams, can be made from 250. g (g)? N2+H2 > NH3 A.152 B.304 C.455 D.500. E.250.
B. 304
A 20.0 g sample of CaCO3 was treated with aqueous H2SO4 producing calcium sulfate, water and 3.65 g of CO2(g) according to: CaCO3(s) + H2SO4(aq) -> CaSO4(s) + H2O + CO2(g). What was the percent yield of CO2? A.33.0 % B.41.5 % C.50.7 % D.83.0 % E.91.1%
B. 41.5 %
In the reaction of aluminum metal and oxygen to make aluminum oxide, how many grams of oxygen gas will react with 2.2 moles aluminum metal? A.94 B.53 C.44 D.26 E.1.7
B. 53
What is the coefficient for water when the following equation is balanced? As(OH)3(s) + H2SO4(aq) → As2(SO4)3(aq) + H2O(l) A.1 B.6 C.12 D.2 E.4
B. 6
What is the sum of the four coefficients when the following equation is balanced?Equation: CS2 + CaO => CO2 + CaS A.5 B.6 C.8 D.10 E.11
B. 6
An oxide of iron has the formula Fe3O4. What mass percent of iron does it contain? A.28% B.72% C.30% D.70% E.0.72%
B. 72% partial/whole > weight of Fe/weight of compound 1670.4 g Fe3/ 231.4 g Fe3O4= .723 g Fe3 *100%= 72%
If 40.0 g of CO2 is produced in the reaction of C2H2 with O2 to form CO2 and H2O, how many grams of H2O are produced in this reaction? A.32.7 g B.8.19 g C.16.37 g D.5.46 g E.none of these
B. 8.19 g
A pure sample of a new chemical compound was analyzed and was found to have the following mass percentages: Al 31.5 %; O 56.1 %; S 12.4 %.Which of these could be the empirical formula of the compound? A.Al5O28S7 B.Al3O9S C.AlO2S2 D.Al4O14S7 E.AlO6S1.5
B. Al3O9S Assume the compound is out of 100g unless otherwise stated, so we can just convert our percentages into grams because it's out of 100g. Convert everything to moles, then to find the empirical formula divide each answer by the smallest answer. You will get the subscripts.
Which of the following has the largest dipole moment? A.CS2 B.AsCl3 C.SO3 D.BF3 E.CCl4
B. AsCl3
Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula? A.C3HO3 B.C3H5O2 C.C2HO3 D.C3H3O4 E.C2H5O4
B. C3H5O2
The molecular structure of NO3- is A. linear B. trigonal planar C. tetrahedral D. bent E. none of these
B.trigonal planar
The formal charge on Cl in the structure of the perchlorate ion showing a resonance form with two Cl-O bonds and two Cl=O bonds is A.-2 B.-1 C.+1 D.+2
C. +1
Estimate ΔE for the reaction: C2H6(g) + Cl2(g) ---> C2H5Cl(g) + HCl(g) given the following average bond energies in kJ/mol: C-C, 348; C-H, 414; Cl-Cl, 242; C-Cl, 327; H-Cl, 431 A.-113 kJ/mol B.-68 kJ/mol C.-102 kJ/mol D.-344 kJ/mol E.276 kJ/mol
C. -102 kJ/mol *Count ALL bonds, so even if the C-C bond doesn't change from the reactants, you would still add that into your calculation. [348 + (6 * 414) + 242] - [348 + (5 *414) + 327 + 431]= 3074-3176= -102 kJ/mol
Using bond energies, calculate an estimate change in energy (kJ) for the following reaction when balanced with the smallest whole number coefficients. H2 + O2 >H2O Bond, BE (kJ) H-H, 432 O-O, 494 H-O, 459 A.-239 kJ B.+239 kJ C.-478 kJ D.+478 kJ E.8 kJ
C. -478 kJ
In the cyanide ion (CN-), the nitrogen has a formal charge of A.-2 B.-1 C.0 D.2 E.More information is needed.
C. 0
How many grams of H 2O (g) are produced when 2.1 grams O 2 (g) are consumed? C4H6 (g) + O2 (g) > CO2 + H2O (g) (unbalanced) A.1.2 B.660 C.0.64 D.2.2 E.0.0020
C. 0.64
Atoms that are sp2 hybridized form ____ pi bond(s). A.2 B.3 C.1 D.0 E.4
C. 1 Sp2 have 3 domains. If we're double bonded to 1 of those domains that uses up 4 e-, with only enough single bonds between the remaining 2 to make a full octet. If we had a triple bond we would have 2 pi bonds, but to make a full octet it be sp.
A single atom of hydrogen has a mass of 1.0 amu, while a mole of hydrogen atoms has a mass of 1.0 g. Select the correct conversion factor between atomic mass units and grams. A.1 amu = 1 g exactly B.1 amu = 6.0 × 1023 g C.1 g = 6.0 × 1023 amu D.1 g = 1.7 × 10¯24 amu E.None of these choices is correct.
C. 1 g = 6.0 × 1023 amu
Sulfuric acid may be produced by the following process: 4FeS2 + 11O2 → 2Fe2O3 +8SO2 2SO2 +O2 → 2SO3 SO3 + H2O → H2SO4 How many moles of H2SO4 will be produced from 8.21 moles of FeS2? A.8.21 B.2.05 C.16.4 D.4.10 E.45.2
C. 16.4
How many of the following: F2, B2, O2, N2, are paramagnetic? A.4 B.1 C.2 D.3 E.0
C. 2 *There are different MO orientations for specifically F2 & O2. The video shows the difference, and fill out each. https://youtu.be/MLA_RVTFt1M F2= dia B2=para O2=para N2=dia *Quick tip: If the element is at 2p, take Ve-4. 4 e- are from 2s, so concentrating on only the e- at 2p would make it easier.
Ammonium carbonate, (NH4)2CO3, contains what percent nitrogen by mass? A.58.3% B.14.6% C.29.2% D.18.8% E.none of these
C. 29.2%
Balance the following equation for the combustion of benzene: C6H6(l) + O2(g) → H2O(g) + CO2(g) A. C6H6(l) + 9O2(g) → 3H2O(g) + 6CO2(g) B. C6H6(l) + 9O2(g) → 6H2O(g) + 6CO2(g) C. 2C6H6(l) + 15O2(g) → 6H2O(g) + 12CO2(g) D. C6H6(l) + 15O2(g) → 3H2O(g) + 6CO2(g) E. 2C6H6(l) + 9O2(g) → 6H2O(g) + 12CO2(g)
C. 2C6H6(l) + 15O2(g) → 6H2O(g) + 12CO2(g)
Consider the skeletal structure shown below: N-C-C-N Draw the Lewis structure and answer the following: How many pi bonds does the molecule contain? A.2 B.6 C.4 D.7 E.0
C. 4
How many moles of O2 are required for the complete reaction of 54.7 g of C2H4 to form CO2 and H2O? A.none of these B.3.90 mol C.5.85 mol D.0.975 mol E.7.80 mol
C. 5.85 mol
What is the percent yield of the following reaction if 23g H2O are obtained from the combustion of 25g of C2H6? 2C2H6(g) + 7O2(g) => 4CO2(g) +6H2O(g) A.60% B.44% C.51% D.49% E.26%
C. 51%
The following equation describes the oxidation of ethanol to acetic acid by potassium permanganate: 3C2H5OH + 4 KMnO4 > 3HC2H3O2 + 4MnO4 + 4KOH + H2O 5.00 g of ethanol and an excess of aqueous KMnO4 are reacted, and 4.26 g of HC2H3O2 result. What is the percent yield? A.100% B.34.6% C.65.4% D.4.26 g HC2H3O2 is impossible since it represents more than 100% yield. E.21.8%
C. 65.4% 5g C2H5OH * (1 mol/ 46g C2H5OH) * (3 mol HC2H3O2/ 3 mol C2H5OH) * (60g HC2H3O2/ 1 mol) = 6.52 g HC2H3O2 percent yield= (actual/theoretical) *100% (4.26 g/ 6.52 g) *100%= 65%
A hypothetical element consists of two isotopes of masses 79.95 amu and 81.95 amu with abundances of 32.3% and 67.7%, respectively. What is the average atomic mass of this element? A.80.95 amu B.79.95 amu C.81.3 amu D.80.6 amu E.81.95 amu
C. 81.3 amu
What is the sum of the coefficients of the following equation when it is balanced using smallest whole numbers? NaNH2 + NaNO3 → NaN3 +NaOH + NH3 A.8 B.6 C.9 D.7 E.5
C. 9
The Cl-Kr-Cl bond angle in KrCl4 is closest to A.360° B.150° C.90° D.109° E.120°
C. 90°
Given the equation 3A + B → C + D, you react 2 moles of A with 1 mole of B. Which of the following is true? A.B is the limiting reactant because 3 A molecules react with 1 B molecule. B.A is the limiting reactant because of its higher molar mass. C.A is the limiting reactant because you need 3 moles of A and have 2. D.Neither reactant is limiting. E.B is the limiting reactant because you have fewer moles of B than A.
C. A is the limiting reactant because you need 3 moles of A and have 2.
Which of the following has only nonpolar bonds? A.H2S B.HCl C.Br2 D.OF2 E.All have only polar bonds
C. Br2
You have a sample of zinc (Zn) and a sample of aluminum (Al). You have an equal number of atoms in each sample. Which of the following statements concerning the masses of the samples is true? A.The mass of the aluminum sample is more than twice as great as the mass of the zinc sample. B.The masses of each sample are equal. C.The mass of the aluminum sample is more than the mass of the zinc sample, but it is not twice as great. D.The mass of the zinc sample is more than twice as great as the mass of the aluminum sample. E.The mass of the zinc sample is more than the mass of the aluminum sample, but it is not twice as great.
D. The mass of the zinc sample is more than twice as great as the mass of the aluminum sample.
A single atom of element Q has a mass of 3.95 x 10-22 g. What is the name of the element Q? A.Helium B.Zinc C.Molybdenum (Z = 42) D.Uranium (Z = 92, atomic mass = 238) E.None of these is correct.
D. Uranium (Z = 92, atomic mass = 238) To identify the element we need to: 3.95*10^-22 g * 6.022*10^23 atoms/mol= 238 > Uranium
The hybridization of the central atom in I3- is: A.sp3 B.d2sp3 C.sp D.dsp3 E.sp2
D. dsp3 Determine shape quickly by, figuring out valence e-. Here we have 7 each I atom, so 21+1 because it has a negative charge. So we have 22 valence e-, to find lone pairs and help us determine the hybridization, subtract the highest multiple of 8 from 22. So 22-16= 6 lone electrons on our core I. So 3 pairs + 2 non-central atoms=dsp3
The hybridization of the central atom in O3 is: A.sp3 B.sp C.d2sp3 D.sp2 E.dsp3
D. sp2
The hybridization of Cl in ClF2+ is A.dsp3 B.sp2 C.d2sp3 D.sp3 E.sp
D. sp3
Electronegativity is a measure of A.the energy needed to remove an electron from an atom. B.the energy released when an electron is added to an atom. C.the magnitude of the negative charge on an electron. D.the attraction by an atom for electrons in a chemical bond. E.the magnitude of the negative charge on a molecule.
D. the attraction by an atom for electrons in a chemical bond.
Aluminum and oxygen react according to the following equation: 4Al + 3O2 > 2Al2O3 In a certain experiment, 4.6 g Al was reacted with excess oxygen. If the product was obtained in 64% yield, how many grams were obtained? A.2.9 B.1.5 C.8.7 D.5.6 E.65
D. 5.6 4.6g Al * (1 mol/ 27g Al) * (2 mol Al2O3/ 4 mol Al) * (102g Al2O3/ 1 mol)= 8.68 g Al2O3 This is at 100%, we only had a 64% yield, so multiply: 8.68 * .64= 5.6 g of Al2O3
What is the hybridization on the N atom in NO2 − and in NO3 −? A.sp2 for NO2− and sp3 for NO3− B.sp3 for NO2− and sp2 for NO3− C.sp for NO2− and sp2 for NO3− D.sp2 for both E.sp3 for both
D. sp2 for both Don't get tricked by NO2! Figure out the lonepairs so you know if it has another domain. Find the valence electrons, NO2- has 18, now we'll subtract the highest multiple of 8. 18-16= 2 lone e- on N, so we know we have 3 domains=sp2.
Based on electronegativity trends in the periodic table, predict which of the following compounds will have the greatest % ionic character in its bonds. A. HCl B. CaI2 C. CaCl2 D. SrF2 E. SrCl2
D.SrF2
Lead can be prepared from galena [lead(II) sulfide] by first heating with oxygen to form lead(II) oxide and sulfur dioxide. Heating the metal oxide with more galena forms the metal and more sulfur dioxide. Write a balanced equation for the overall reaction by adding the balanced equations for the two steps. A.2PbS + O2 => 2Pb + SO2 B.2PbS + 2O2 => 2Pb + SO2 C.PbS + 2O2 => 2Pb + SO2 D.2PbS + O2 => 2Pb + 2SO2 E.PbS + O2 => Pb + SO2
E. PbS + O2 => Pb + SO2
If 1.0 mole of CH4 and 2.0 moles of Cl2 are used in the reaction CH4 + 4Cl2 => CCl4 + 4HCl then which of these statements is TRUE? A.All of the CH4 will be used up. B.The theoretical yield of CCl4 is 1.0 mole. C.Some Cl2 will be left over. D.More CH4 should be added to ensure all the Cl2 will be used. E.The theoretical yield of HCl is 2.0 moles.
E. The theoretical yield of HCl is 2.0 moles.
If 1.0 mole of CH4 and 2.0 moles of Cl2 are used in the reaction CH4 + 4Cl2 => CCl4 + 4HCl then which of these statements is TRUE? A.All of the CH4 will be used up. B.The theoretical yield of CCl4 is 1.0 mole. C.Some Cl2 will be left over. D.More CH4 should be added to ensure all the Cl2 will be used. E.The theoretical yield of HCl is 2.0 moles.
E. The theoretical yield of HCl is 2.0 moles.
How many sigma (σ) bonds and pi (π) bonds are in propene, CH2CHCH3? A.six σ, two π B.seven σ, one π C.seven σ, two π D.eight σ, zero π E.eight σ, one π
E. eight σ, one π
What is the name of P4Se3? A.phosphorus selenide B.phosphorus triselenide C.tetraphosphorus selenide D.phosphoric selenide E.tetraphosphorus triselenide
E. tetraphosphorus triselenide
Which of the following compounds has the same percent composition by mass as styrene, C8H8? A.acetylene, C2H2 B.benzene, C6H6 C.cyclobutadiene, C4H4 D.α-ethyl naphthalene, C12H12 E.all of these
E. all of these They all have the same ratio of 1:1 so it's everything.
How many of the following: F2, B2, O2, N2, are paramagnetic? A.4 B.1 C.3 D.0 E.2
E.2
A molecule which contains polar bonds will always have a dipole moment. True False
False
The reactant with the highest molar mass is always the limiting reactant.
False
Paramagnetism is associated with paired electrons. True False
False Paramagnetism: substance is attracted in the inducing magnetic field. Involves unpaired e-.
Paramagnetism is associated with paired electrons. True False
False Paramagnetism-unpaired-attracted Diagmagnetism-paired-repelled *di=2=togeter=paired
How many of the following statements are true concerning chemical equations? I. Coefficients can be fractions. II. Subscripts can be fractions. III. Coefficients represent the relative masses of the reactants and/or products. IV. Changing the subscripts to balance an equation can only be done once. V. Atoms are conserved when balancing chemical equations.
I. and V.
A metal oxide with the formula MO contains 22.55% oxygen. In the box below, type the symbol for the element represented by M.
Mn Since it isn't specificed, it's okay for us to assume this is out of 100g so we can say we have 22.55g of O and 77.4g of M. Find moles of O> 1.4 mol of O Divide 77.4 g M/1.4 mol= 55 g/mol > Mn on Periodic Table
The mixing of native atomic orbitals to form special orbitals for bonding is called __________.
hybridization
Calculate the mass in grams of 45.095 mol of Na 2HPO 4 * 7H 2O.
12,089 ± 2%
An ionic compound contains only a metal, M, and sulfur. If analysis indicates that a 3.37 g sample of the compound contains 1.97 g of M, what mass of sulfur in g is contained in 367 g of the mineral?Enter your answer in decimal format with two decimal places and no units.
152.5 ± 2%
How many molecules are contained in 5.78 moles of H2O? Once you have the answer, determine the log (base 10) of it and enter that value with three decimal places into the answer box. Do not add units.
24.542 +- 2%
What is the molecular (formula) mass of a compound with the formula M2(XO3)3 if the atomic mass of M is 25.1 amu and that of X is 45.9 amu?
332 ± 2%
What is the formula mass of a compound with the formula M3(XO3)2 if the atomic mass of M is 57.1 amu and that of X is 43.7 amu? Do not enter units with your answer.
355 ± 2%
H O | || HC-C-C-C≡N | | H H Specify the hybridization of each carbon atom. C-1 C-2 C-3 C-4 C-5 A. sp 2 sp 2 sp 2 sp 3 sp B. sp 2 sp 2 sp 2 sp 3 sp 3 C. sp 2 sp 2 sp 3 sp 3 sp 2 D. sp 2 sp sp sp 2 sp E. sp 2 sp 2 sp 3 sp 3 sp 3
A. sp 2 sp 2 sp 2 sp 3 sp
Which answer represents the empirical formula of the molecule shown below? A.C2H3O2 B.C4H6O4 C.CH2O D.CH3O E.CHO
A. C2H3O2
H3C-C=O-CH=CH2 Which statement about the molecule is false? A. Oxygen is sp3 hybridized. B. There are some H-C-H bond angles of about 109° in the molecule. C. This molecule contains 28 valence electrons. D. There are 10 sigma and 2 pi bonds. E. C-2 is sp2 hybridized with bond angles of 120°.
A. Oxygen is sp3 hybridized.
The molecular structure of AsCl5 is A.trigonal bipyramidal B.square pyramidal C.distorted tetrahedral D.octahedral E.none of these
A. trigonal bipyramidal
Use the molecules below to answer the next three questions. (They're all aromatic rings) C6H6 , C6H8, C6H10 Which molecule(s) have equivalent C-C bonds throughout the molecule? A. I B. II C. III D. all of the above E. none of the above
A. I
The molecular structure of I3- is A.linear B.trigonal planar C.tetrahedral D.bent E.none of these
A. linear VSPER theory and molecular shapes 2 things=sp=180
Consider the molecule and the following hybridization choices: H O | || HC-C-C-C≡N | | H H Reference: What is the hybridization of the nitrogen atom? A.sp B.dsp3 C.sp2 D.sp3 E.d2sp3
A. sp
The hybridization of the phosphorus atom in the cation PH2+ is: A.sp2 B.sp3 C.dsp D.sp E.none of these
A. sp2 Draw out the lewis structure, don't forget we removed an e-!
The hybridization of the central atom in NO3- is A.sp2 B.p3 C.sp D.dsp2 E.sp3
A. sp2 Valence e- + charge in total: N=5 + (6 *3)= 23 +1=24 e- Quick way to find lone pairs, is to find the highest multiple of 8 that you can subtract, here it's 24, so we have 0 lone pairs. So there are 3 "things" around N, so its sp2.
The atomic mass of rhenium is 186.2. Given that 37.1% of natural rhenium is rhenium-185, what is the other stable isotope? A. Re- 187 B. Re- 183 C. Re- 181 D. Re- 189 E. Re-190
A. Re- 187 percent abundance= (percent * mass) + . . . . 186.2= (.371 & 185) + (62.9 + x) Solve for x 117.6=62.9x 1.87=x 1.87 * 100= Re-187
The molecular structure of SO32- is A.trigonal pyramidal B.tetrahedral C.square planar D.octahedral E.none of these
A. trigonal pyramidal
Which of the following elements is the most electronegative? A.S B.Ru C.Si D.Te E.Cs
A.S *Electronegativity increases up a group and to the right of a period. So the elements closest to the top right are the most electronegative.
How many resonance structures can be drawn for the molecule O3? A.1 B.2 C.3 D.4 E.5
B. 2
A sample of ammonia has a mass of 82.9 g. How many molecules are in this sample? A.1.24 × 1023 molecules B.2.93 × 1024 molecules C.4.87 molecules D.1.64 × 10-15 molecules E.4.99 × 1025 molecules
B. 2.93 × 10^24 molecules Ammonia= NH3 (82.9 g NH3) * (1mol/17g NH3) * (6.022*10^23/ 1 mol)= 2.94 * 10^24
Consider the compound crotonaldehyde, whose skeleton is: CH3-CH-CH-CHO How many nonbonding electrons appear in the Lewis structure of this molecule? A.2 B.4 C.6 D.8 E.10
B. 4
The best Lewis structure for sulfuric acid has zero formal charges, sulfur as the central atom, and no bonds between S and H. How many single and double bonds, respectively, are there in this Lewis structure? A.2 single, 4 double B.4 single, 2 double C.4 single, no double D.6 single, no double E.5 single, 1 double
B. 4 single, 2 double Sulfuric Acid: H2SO4 is a common oxyacid, it would be good to memorize these alongside common polyatomic ions and acids that do not contain oxygen.
Rank the members of this set of compounds in order of decreasing ionic character of their bonds. Use partial charges to indicate the bond polarity of each bond.BF3, NF3, CF4. A. C-F > B-F > N-F δ -δ + δ -δ + δ -δ + B. B-F > C-F > N-F δ +δ - δ +δ - δ +δ - C. N-F > C-F > B-F δ +δ - δ+ δ - δ+ δ - D. N-F > B-F > C-F δ -δ + δ -δ + δ -δ + E. none of these
B. B-F > C-F > N-F δ +δ - δ +δ - δ +δ - *Fluorine is the same in all of them, so refer to the electronegative trend to determine their rank. To have a compound with the MOST ionic character, it has to have a smaller electronegativity than F. N is the closest and most similar in electronegativity out of the 3. This means that N would be at the bottom of our ranking. To get that strong ionic character where F has a strong e- density to its side, we would want one with the weakest electronegativity, so that would be B. And make it at the TOP of our ranking.
An organic compound has the molecular formula, C6H12O4. Which of these could be its empirical formula? A.C6H12O4 B.C3H6O2 C.CH2O D.C3H4O2 E.C2H3O
B. C3H6O2
Order the following by decreasing bond strength: C≡C, C=C, C-C A. none of these B. C≡C, C=C, C-C C. C≡C, C-C, C=C D. C-C, C=C, C≡C E. C=C, C-C, C≡C
B. C≡C, C=C, C-C As bond strength INCREASES bond length decreases Triple =strongest and shorter double=strong and a little longer single=least strong and long *Its easier to break single bonds than triple bonds
Which of the molecules below has/have a molecular dipole moment? CS2 CCl4 Cl2 SCl2 BrCl A.BrCl only B.SCl2 and BrCl C.CS2, SCl2 and BrCl D.CS2, CCl4 and Cl2 E.CCl4 and Cl2
B. SCl2 and BrCl
When a carbon atom has sp3 hybridization, it has A.one π bond and three σ bonds B.four σ bonds C.three π bonds and one σ bond D.four π bonds E.two π bonds and two σ bonds
B. four σ bonds
The molecular structure of PCl4+ is A.trigonal pyramidal B.tetrahedral C.square planar D.octahedral E.none of these
B. tetrahedral
How many electrons are involved in pi bonding in benzene, C6H6? A.30 B.6 C.3 D.12 E.18
B. 6 This makes a benzene ring with 3 double bonds. If we pick 3 thats a mistake, because it's asking for how many electrons make up those pi bonds. There are 2 e- that make up pi bonds, so 3*2= 6 e-
Which of the following molecules is non-polar overall? A.H2S B.CCl4 C.SF2 D.SF4 E.OCl2
B. CCl4
Draw the Lewis structures of the molecules below and use them to answer the following questions: I. BH3 II. NO2 III. SF6 IV. O3 V. PCl5 Which of these molecules show resonance? A. I, II B. II, IV C. II, V D. III, IV E. III, V
B. II, IV
Which of the following contains ionic bonding? A. CO B. SrCl2 C. Al D. OCl2 E. HCl
B. SrCl2 *Recall the trend for electronegativity, ionic bonds are between a metal and a non-metal where usually the non-metal is more electronegative and has a higher e- density around it. That is our ionic bond. Find a m x nm compound with a large electronegative difference.
After an atom has lost an electron it becomes a/an ______ and has a _______ charge. A. anion, positive B. cation, positive C. anion, negative D. cation, negative E. nucleus, positive
B. cation, positive
Chlorous acid, HClO2, contains what percent hydrogen by mass? A.5.18% B.1.92% C.1.47% D.25.0% E.23.4%
C. 1.47%
How many atoms of hydrogen are present in 2.92 g of water? A.4.52 × 10^19 B.3.52 × 10^24 C.1.95 × 10^23 D.9.76 × 10^22 E.8.72 × 10^23
C. 1.95 × 10^23 Convert from mols > use the mole ratio of H mols/H2O mols > convert to atoms of H.
How many oxygen atoms are there in 2 formula units of Al2(SO3)3? A.12 B.9 C.18 D.11 E.21
C. 18
There are two isotopes of Element X. Their percent abundances and atomic masses are: X-20, 62.96% X-21, 37.04% Calculate the weighted average atomic mass in amu. A.2037 B.20.63 C.20.37 D.12.59 E.20.50
C. 20.37
Calculate the mass, in grams, of 0.350 mol Cu. A.18.5 B.20.6 C.22.2 D.63.5 E.181
C. 22.2
Calculate the number of molecules in 2.86 g . A.6.48 x B.1.30 x C.3.91 x D.1.17 x E.9.26 x
C. 3.91 x
In the Lewis structure for elemental nitrogen (N2) there is (are) A.a single bond between the nitrogens B.a double bond between the nitrogens C.a triple bond between the nitrogens D.three unpaired electrons E.none of the above
C. a triple bond between the nitrogens If we left it at a single bond we would still have 4 lone pairs between the 2, we can create a triple bond (6 e- shared) with 2 e- in their remaining lone pair to reach an octet for both Nitrogens.
What is the name of the acid formed when H2S gas is dissolved in water? A. sulfuric acid B. sulfurous acid C. hydrosulfuric acid D. hydrosulfurous acid E. sulfidic acid
C. hydrosulfuric acid Binary Acids Add hydro- + -ic acid if the anion ends in -ide Oxyacids- anion with oxygen >Add -ous acid if it ends with -ite >HClO > hypochlorite > hypochlorous acid >HClO2 >Chlorite > Chlorous acid Add -ic acid if the anion end in -ate >HClO3 > Chlorate > Chloric acid >HClO4 > Perchlorate > Perchloric acid
The molecular structure of BrF6+ is A.trigonal pyramidal B.none of these C.octahedral D.trigonal planar E.bent
C. octahedral
The compound, NaH2PO4, is present in many baking powders. What is its name? A. sodium biphosphate B. sodium hydrogen phosphate C. sodium dihydrogen phosphate D. sodium hydrophosphate E. sodium dihydride phosphate
C. sodium dihydrogen phosphate
How many sigma (σ) bonds and pi (π) bonds are in carbon dioxide? A.three σ, zero π B.two σ, one π C.two σ, two π D.one σ, two π E.zero σ, three π
C. two σ, two π
The bond angles about the carbon atom in the formaldehyde molecule, H2C=O, are about: A.60° B.109° C.120° D.90° E.180°
C. 120° Count the # of "things" around the central atom Carbon. We have 4 things=sp3=120 degrees
How many unpaired electrons in the F22+ ion are based on molecular orbital theory? The order of the molecular orbitals are (σ2s) (σ*2s) (σ2p) (π2p) (π*2p) (σ*2p). A.0 B.1 C.2 D.4 E.3
C. 2
Which of the following compounds will contain the bonds with the largest % ionic character? A. H2O B. LiI C. RbF D. CaO E. HCl
C. RbF
As indicated by Lewis structures, which of the following would probably not exist as a stable molecule? A. CH3OH B. CH2O C. CH3O D. C2H2 E. C3H4
C. CH3O Notice that in all the other compounds O is either double bonded to C or has a H attached. CH3O can not double bond with C, so it between C and O, its just a single bond with 3 2 lone pairs and 1 e- on O. Here, O is a free radical, meaning it REALLY wants to fill its octet and will be very reactive- thus unstable.
Tetracyanoethylene has the skeleton shown below: From its Lewis structure determine the following: NCNC-C-C-CNCN How many nonbonded electron pairs are in the molecule? A.0 B.5 C.4 D.8 E.2
C.4
The compound, NaH2PO4, is present in many baking powders. What is its name? A.sodium biphosphate B.sodium hydrogen phosphate C.sodium dihydrogen phosphate D.sodium hydrophosphate E.sodium dihydride phosphate
C.sodium dihydrogen phosphate H2PO4 is on the list of common polyatomic ions to memorize.
Calculate the following:Mass fraction of P in tetraphosphorus hexaoxide A.84.5 B.0.744 C.0.845 D.0.563 E.43.7
D. 0.563
What is the mass of one mole of acetylsalicylic acid (aspirin), C9H8O4? A.29 g B.108 g C.196 g D.180 g E.none of the above
D. 180 g
Lithium forms compounds which are used in dry cells and storage batteries and in high-temperature lubricants. It has two naturally occurring isotopes, 6Li (isotopic mass = 6.015121 amu) and 7Li (isotopic mass = 7.016003 amu). Lithium has an atomic mass of 6.9409 amu. What is the percent abundance of lithium-6? A.92.50% B.86.66% C.46.16% D.7.503% E.6.080%
D. 7.503%
What is the empirical formula and empirical formula mass for the following compound?Al2Br6 A.Al2Br6, 533.5 g/mol B.Al3Br, 160.9 g/mol C.AlBr2, 186.8 g/mol D.AlBr3, 266.7 g/mol E.None of these
D. AlBr3, 266.7 g/mol
Predict which of the following bonds has the greatest bond energy. A. C-Cl B. C-C C. C=C D. C-triple bond-C E. Cl-Cl
D. C-triple bond-C triple=strongest=closest=higher bond energy
Which of the following is in the order of decreasing bond strength? A. Cl − Cl, I − I, Br − Br B. Br − Br, Cl − Cl, I − I C. I − I, Br − Br, Cl − Cl D. Cl − Cl, Br − Br, I − I E. I − I, Cl − Cl, Br − Br
D. Cl − Cl, Br − Br, I − I They're all the same, we can determine their bond length by recalling the radius. If it's small, it doesn't want bonds broken and would require more energy. So going down a group, radius increases so Cl is the smallest with the highest bond strength to I-I with the weakest bond strength.
The formula of the compound formed in the reaction between lithium and sulfur is A.LiS B.LiS2 C.Li2S3 D.Li2S E.none of these
D. Li2S Recall the formal charge of the elements in the periodic table *Look it up if unsure*. All group 1 metals have a +1 charge, so Li +1 and S -2 charge. We want enough Li to balance the -2 charge, so 2 Li will have an overall +2 charge to balance out.
Which of the following has the smallest radius? A.F - B.Ne C.O2- D.Mg2+ E.Na +
D. Mg2+
Give the charge and full ground-state electron configuration of the monatomic ion most likely to be formed by the element.Rb A. Rb+: 1s22s22p63s23p64s23d104p65s2 B. Rb+: 1s22s22p63s23p64s23d104p65s1 C. Rb+: 1s22s22p63s23p64s23d104p5 D. Rb+: 1s22s22p63s23p64s23d104p6 E. none of these
D. Rb+: 1s22s22p63s23p64s23d104p6
In the molecular orbital description of CO (assuming it has the same MO energy levels as N2): A.The highest energy electrons occupy antibonding orbitals. B.Six molecular orbitals contain electrons. C.There are two unpaired electrons. D.The bond order is 3. E.All of the above are false.
D. The bond order is 3. Look at electron configuration of each: C- 1s2, 2s2, 2p2 O- 1s2,2s2, 2p4 If you fill out your molecular orbital configuration, you have 4 e- in total that fill up the 2s sigma and pi orbitals. A total of 6 e- fill up the 2p orbitals. We would have full bonding 2p sigma and pi orbitals. If you look up a video for molecular orbital of N2, it will have the same configuration. Bond order= (bonding-antibonding)/2 Bond order of CO= (6-0)/2=3 Higher the bond order=more stable the bond A. Highest energy is in the 2p pi bond B. Only 4 orbitals have electrons- two 2s orbitals and 2 2p orbitals C. All of our e- are paired
Which atomic or hybrid orbitals are involved in bonding and which as lone pair orbitals for N2H2? A. bonding: s on H, sp2 on N lone pair: p on N B. bonding: sp2 on both H and N lone pair: p on N C. bonding: s on H, p on N lone pair: sp2 on N D. bonding: s on H, sp2 and p on N lone pair: sp2 on N E. none of these
D. bonding: s on H, sp2 and p on N lone pair: sp2 on N
Atoms with greatly different electronegativity values are expected to form. A. no bonds B. covalent bonds C. triple bonds D. ionic bonds E. none of these
D. ionic bonds
The molecular structure of BeF3- is A.trigonal pyramidal B.none of these C.octahedral D.trigonal planar E.bent
D. trigonal planar
The bond angle in H2Se is about: A.180° B.90° C.60° D.109° E.120°
D. 109° Count the number of valence e- and draw out the lewis structure so you can see the lone pairs. Lone pairs take up more space than the H so it pushes them both down. We have 2 lone pairs, and 2 H so we have 4 "things" around our central atom so it's sp3 with 2 elements= bent with 109 degrees
Assuming that it has the same order of MO energies as N2, the CO molecule should have the bond order: A.0 B.1 C.2 D.3 E.4
D. 3
Consider the molecular orbital energy level diagrams for O2 and NO. Which of the following is true? I. Both molecules are paramagnetic. II. The bond strength of O 2 is greater than the bond strength of NO. III. NO is an example of a homonuclear diatomic molecule. IV. The ionization energy of NO is smaller than the ionization energy of NO +. A. I and II B. II and III C. I, II, and IV D. I and IV E. I only
D. I and IV
Which of the following exhibits the greatest electronegativity? A. Al B. As C. Ge D. P E. Si
D. P
Which of the following exhibits resonance? A. NH3 B. PCl5 C. H2O D. SO2 E. At least two of the molecules (A-D) exhibit resonance.
D. SO2 A-H can not form double bonds B- Full C- H can not form double bonds E- Not A.
Which of the following has the smallest radius? A. S2- B. Cl - C. Ar D. K+ E. Ca2+
E. Ca2+ *If we have more shells=bigger the radius *Same # of shells=more protons=smaller *Same number of protons (isoelectronic)= more e-=bigger radius Here we see case 2, where Ca has 20 protons pulling on 18 e-, thus creating a smaller radius. While S has 16 protons and 18 e- with a bigger radius because there is less of a pull from the nucleus.
A chloride of rhenium contains 63.6% rhenium. What is the formula of this compound? A.ReCl5 B.Re2Cl3 C.ReCl D.ReCl7 E.ReCl3
E. ReCl3
Which of the following types of molecules always has a dipole moment? A.Tetrahedral molecules (four identical bonds equally spaced). B.Trigonal planar molecules (three identical bonds equally spaced). C.None has a dipole moment. D.Linear molecules with two identical bonds. E.Trigonal pyramid molecules (three identical bonds).
E. Trigonal pyramid molecules (three identical bonds).
The hybridization of Se in SeF6 is A.sp B.sp2 C.sp3 D.dsp3 E.d2sp3
E. d2sp3
The formula of calcium oxide is CaO. What is the formula of the ionic compound containing calcium and permanganate ions? A. CaMnO4 B. Ca2MnO4 C. Ca3(MnO4)2 D. Ca2(MnO4)3 E. none of these
E. none of these Recall Ca has a +2 charge, we know this by memorizing the charges of each group. You have to memorize the common polyatomic ions, permanganate > MgO4 has a -1 charge. Now we have to balance them, so we have an equal # of + and - charges. If we have 2 molecules of MgO4, then it'll have a -2 charge and will balance out the +2 charge on Ca. So our formula is: Ca(MgO4)2
The hybridization of the lead atom in PbCl4 is A.dsp2 B.sp2 C.d2sp3 D.dsp3 E.none of these
E. none of these check for any lone pairs by determining # of valence e-. Here we have 32 ve- to find the lone e- take the highest multiple of 8. Here it's 32-32=0 lone e-. So we just have 4 domains= sp3
The bond angles about the carbon atom in the formaldehyde molecule, H2C=O, are about: A.90° B.60° C.109° D.180° E.120°
E. 120°
Which of the following has the largest radius? A. K+ B. Cl- C. Ca2+ D. Ar E. S2-
E. S2-
The hybridization of the central atom in I3- is: A.sp2 B.d2sp3 C.sp3 D.sp E.dsp3
E. dsp3
In the COCl2 molecule, carbon is the central atom. Based on the best Lewis structure for COCl2, what is the formal charge on carbon? A. +1 B. -1 C. +2 D. -2 E. 0
E. 0 Solve by: *Recall Valence electrons can easily be determined by looking at the group #. Creating a lewis dot structure. It's best to double check the amount of lone pairs with this formula: Lone Pairs: Ve-(8*# of atoms bonded to central atom) ------------------------------------------------- 2 Here it would be Ve=4+6+7*(2)=24 total e- Lone Pairs=24-(8*3)/2 > (24-24)/2 > 0/2 >0 lone pairs, so we can assume C reaches an octet with a double bond to O because it is less electronegative than Cl, and thus more willing to share e-. Now that we have the correct structure we can determine formal charge with this formula: FC=Ve-(# bonds + dots)= 4-(4-0)=0 charge on C. # of bonds=count all bonds, double bonds count for 2, triple would count for 3, here we have 1 double and 2 singles= 4 bonds, and dots refer to lone pairs. Here we don't have any, but is we did have a pair, it would count EACH dot.
What is the bond order of C2+? A.2 B.0 C.1 D. (1/2) E.1 (1/2)
E. 1 (1/2) Bond order= # of bonds/# of domains This one would be 3/2=1.5 single= 1 double= 2 triple= 3
Which is the least polar bond? A. O-H B. S-F C. P-F D. C-F E. N-Cl
E. N-Cl Check the electronegativities of the atoms involved in each bond. The greatest difference in electronegativity will correspond to the most polar bond.
The formula of calcium oxide is CaO. What is the formula of the ionic compound containing calcium and permanganate ions? A. CaMnO4 B.Ca2MnO4 C.Ca3(MnO4)2 D.Ca2(MnO4)3 E.none of these
E.none of these To find the actual answer, first recall the charges of each and figure out how much of each ion is needed so they both have the SAME charge. Ca +2 and O+2 are already balanced, and lets us know Ca has a +2 charge, and MnO4- needs to MATCH it to have a balanced compound. Ca with +2 charge needs 2 molecules of MnO4- to balance it. It would look like this: Ca(MnO4)2 Where Ca 2+ is balanced with (MnO4)2 and it's 2- overall charge.
A metal oxide with the formula MO2 contains 21.23% oxygen by mass. Type the symbol for the element represented by M in the box below.
Sn
A metal oxide with the formula MO contains 15.44% oxygen. In the box below, type the symbol for the element represented by M
Sr
Whenever a set of equivalent tetrahedral atomic orbitals is required, an atom will adopt a set of sp3 orbitals. True False
True
