Q&A Hero

Q: What mass of dinitrogen monoxide, N2O, contains the same number of molecules as 3.00 g of trichlorofluoromethane, CCl3F? A) 0.106 g B) 0.961 g C) 1.04 g D) 9.37 g

Q: What is the molar mass of butane if 5.19 1016 molecules of butane weigh 5.00 g?A) 58.0 g/molB) 172 g/molC) 232 g/molD) 431 g/mol

Q: What is the identity of substance X if 0.380 mol of X weighs 17.5 g? A) NO2 B) NO3 C) N2O D) N2O4

Q: How many oxygen atoms are in 3.00 g of sodium dichromate, Na2Cr2O7? A) 0.0801 oxygen atoms B) 9.85 1020 oxygen atoms C) 6.90 1021 oxygen atoms D) 4.83 1022 oxygen atoms

Q: What is the mass of 8.50 1022 molecules of NH3? A) 0.00830 g B) 0.417 g C) 2.40 g D) 120 g

Q: How many iron(II) ions, Fe2+ are there in 5.00 g of FeSO4? A) 5.46 10-26 iron (II) ions B) 1.98 1022 iron (II) ions C) 1.83 1025 iron (II) ions D) 4.58 1026 iron (II) ions

Q: How many moles are in 1.50 g of ethanol, CH3CH2OH? A) 0.0145 mol B) 0.0326 mol C) 30.7 mol D) 69.0 mol

Q: What is the mass of 0.500 mol of dichlorodifluoromethane, CF2Cl2? A) 4.14 10-3 g B) 60.5 g C) 121 g D) 242 g

Q: What is the mass of a single chlorine molecule, Cl2? A) 5.887 10-23 g B) 1.177 10-22 g C) 35.45 g D) 70.90 g

Q: What is the molar mass of hydrogen gas? A) 1.00 g/mol B) 2.00 g/mol C) 6.02 1023 g/mol D) 1.20 1023 g/mol

Q: What is the molar mass of calcium permanganate? A) 159 g/mol B) 199 g/mol C) 216 g/mol D) 278 g/mol

Q: What is the molar mass of Co(NO3)2? A) 90 g/mol B) 121 g/mol C) 152 g/mol D) 183 g/mol

Q: What is the molar mass of aspartic acid, C4O4H7N? A) 43 g/mol B) 70 g/mol C) 133 g/mol D) 197 g/mol

Q: What is the mass of an atom of the element hydrogen?A) 2.0 gB) 1.0 gC) 3.4 10-24 gD) 1.7 10-24 g

Q: 1.00 mole of O2 contains the same number of oxygen atoms as A) 0.667 mole of O3. B) 1.00 mole of CH3CO2H. C) 2.00 mole of CH3CH2OH. D) all of the above.

Q: 1.00 mole of O2 contains the same number of molecules as A) 0.667 mole of O3. B) 1.00 mole of CH3CO2H. C) 2.00 mole of CH3CH2OH. D) all of the above.

Q: Given the chemical equation: N2 + 3 H2 -> 2 NH3. On a macroscopic level, what do the coefficients mean?A) 1 atom of nitrogen reacts with 3 atoms of hydrogen to give 2 atoms of ammonia.B) 1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia.C) 1 molecule of nitrogen reacts with 3 molecules of hydrogen to give 2 molecules of ammonia.D) all of the above

Q: Given the chemical equation: N2 + 3 H2 -> 2 NH3. On a microscopic level, what do the coefficients mean?A) 1 atom of nitrogen reacts with 3 atoms of hydrogen to give 2 atoms of ammonia.B) 28 g of nitrogen reacts with 6 grams of hydrogen to give 34 grams of ammonia.C) 1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia.D) 1 molecule of nitrogen reacts with 3 molecules of hydrogen to give 2 molecules of ammonia.

Q: Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid. What is the stoichiometric coefficient for sulfuric acid when the chemical equation is balanced using the lowest, whole-number stoichiometric coefficients? A) 1 B) 2 C) 3 D) none of these

Q: Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal. What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest, whole-number stoichiometric coefficients? A) 1 B) 2 C) 3 D) 4

Q: What is the sum of the coefficients when the following equation is balanced using the lowest, whole numbered coefficients?___ B2O3(s) + ___ HF(l) -> ___ BF3(g) + ___ H2O(l)A) 8B) 11C) 15D) none of these

Q: What is the sum of the coefficients when the following equation is balanced using the lowest, whole numbered coefficients?___ PH3(g) + ___ O2(g) -> ___ P4O10(s) + ___ H2O(g)A) 10B) 12C) 19D) 22

Q: What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest, whole-number coefficients___ C3H8O(l) + ___ O2(g) -> ___ CO2(g) + ___ H2O(l)A) 3B) 5C) 7D) 9

Q: Which one of the following statements about balanced equations is true? A reaction is balanced by A) changing the charge on an ion. B) changing the formula of the molecule. C) multiplying by suitable coefficients. D) rearranging atoms in a molecule.

Q: Which one of the following statements about balanced equations is false? In a balanced reaction A) atoms must be balanced on both sides of the reaction arrow. B) mass must be conserved. C) molecules must be balanced on both sides of the reaction arrow. D) net charge must be balanced on both sides of the reaction arrow.

Q: What is the empirical formula of benzene, C6H6?

Q: What is the molarity of a solution prepared by diluting 25 mL of 2.0 M HCl with enough water to make 250 mL of solution?

Q: What is the molarity of a solution prepared by dissolving 0.80 g of NaOH in enough water to make 250 mL of solution?

Q: If 4.0 g of H2 react with 4.0 g of F2 in the reaction shown below, what is the limiting reactant?H2 + F2 -> 2 HF

Q: The balanced equation for the decomposition of water is shown below.2 H2O -> 2 H2 + O2If 0.72 g of water react completely in this reaction, what is the theoretical yield of H2?

Q: The balanced equation for the gaseous state oxidation of ammonia is shown below.4 NH3 + 5 O2 -> 4 NO + 6 H2OHow many moles of O2 are required to react with 1.2 mole of NH3?

Q: How many moles are in 7.8 g of acetamide, CH3CONH2?

Q: To the nearest whole number, the molar mass of Cu(NO3)2 is ________ g/mol.

Q: When the reaction C4H10 + O2 -> CO2 + H2O is balanced using the smallest whole number coefficients, the coefficient in front of O2 is ________.

Q: A balanced equation has the same numbers and kinds of ________ on both sides of the reaction arrow.

Q: Combustion analysis of 1.200 g of an unknown compound containing carbon, hydrogen, and oxygen produced 2.086 g of CO2 and 1.134 g of H2O. What is the empirical formula of the compound?A) C2H5OB) C2H5O2C) C2H10O3D) C3H8O2

Q: Combustion analysis of an unknown compound containing only carbon and hydrogen produced 0.2845 g of CO2 and 0.1451 g of H2O. What is the empirical formula of the compound? A) CH2 B) C2H5 C) C4H10 D) C5H2

Q: Which one of the following is not an empirical formula? A) CHO B) CH2O C) C2H4O D) C2H4O2

Q: What is the empirical formula of a substance that contains 2.64 g of C, 0.444 g of H, and 3.52 g of O? A) CH2O B) C2H4O2 C) C2H4O3 D) C3H4O4

Q: Which one of the following contains 39% carbon by mass? A) C2H2 B) CH4 C) CH3NH2 D) CO2

Q: When 280. mL of 1.50 10-4 M hydrochloric acid is added to 125 mL of 1.75 10-4 M Mg(OH)2, the resulting solution will be A) acidic. B) basic. C) neutral. D) It is impossible to tell from the information given.

Q: Balance the chemical equation given below, and determine the number of milliliters of 0.00300 M phosphoric acid required to neutralize 45.00 mL of 0.00150 M calcium hydroxide.______ Ca(OH)2(aq) + ______ H3PO4(aq) -> ______ Ca3(PO4)2(aq) + ______ H2O(l)A) 3.04 mLB) 15.0 mLC) 22.5 mLD) 33.8 mL

Q: In an acid-base neutralization reaction 38.74 mL of 0.500 M potassium hydroxide reacts with 50.00 mL of sulfuric acid solution. What is the concentration of the H2SO4 solution? A) 0.194 M B) 0.387 M C) 0.775 M D) 1.29 M

Q: How many milliliters of 0.550 M hydriodic acid are needed to react with 15.00 mL of 0.217 M CsOH?HI(aq) + CsOH(aq) -> CsI(aq) + H2O(l)A) 0.0263 mLB) 0.169 mLC) 5.92 mLD) 38.0 mL

Q: If 100. mL of 0.400 M Na2SO4 is added to 200. mL of 0.600 M NaCl, what is the concentration of Na+ ions in the final solution? Assume that the volumes are additive. A) 0.534 M B) 0.667 M C) 1.00 M D) 1.40 M

Q: How many milliliters of 0.200 M FeCl3 are needed to react with an excess of Na2S to produce 1.38 g of Fe2S3 if the percent yield for the reaction is 65.0%? 3 Na2S(aq) + 2 FeCl3(aq) → Fe2S3(s) + 6 NaCl(aq) A) 25.5 mL B) 43.1 mL C) 51.1 mL D) 102 mL

Q: When 31.2 mL of 0.500 M AgNO3 is added to 25.0 mL of 0.300 M NH4Cl, how many grams of AgCl are formed?AgNO3(aq) + NH4Cl(aq) -> AgCl(s) + NH4NO3(aq)A) 1.07 gB) 2.24 gC) 3.31 gD) 6.44 g

Q: How many grams of CaCl2 are formed when 15.00 mL of 0.00237 M Ca(OH)2 reacts with excess Cl2 gas?2 Ca(OH)2(aq) + 2 Cl2(g) -> Ca(OCl)2(aq) + CaCl2(aq) + 2 H2O(l)A) 0.00197 gB) 0.00394 gC) 0.00789 gD) 0.0507 g

Q: How many milliliters of 0.260 M Na2S are needed to react with 40.00 mL of 0.315 M AgNO3?Na2S(aq) + 2 AgNO3(aq) -> 2 NaNO3(aq) + Ag2S(s)A) 24.2 mLB) 48.5 mLC) 66.0 mLD) 96.9 mL

Q: A student prepared a stock solution by dissolving 10.0 g of KOH in enough water to make 150. mL of solution. She then took 15.0 mL of the stock solution and diluted it with enough water to make water to make 65.0 mL of a final solution. What is the concentration of KOH for the final solution? A) 0.274 M B) 0.356 M C) 2.81 M D) 3.65 M

Q: A student dissolved 4.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution. He took 4.00 mL of the stock solution and then diluted it with water to give 275. mL of a final solution. How many grams of NO3- ion are there in the final solution? A) 0.0197 g B) 0.0394 g C) 0.0542 g D) 0.108 g

Q: How many mL of a 0.175 M FeCl3 solution are needed to make 450. mL of a solution that is 0.300 M in Cl- ion? A) 0.771 mL B) 257 mL C) 771 mL D) It is not possible to make a more concentrated solution from a less concentrated solution.

Q: How many milliliters of a 9.0 M H2SO4 solution are needed to make 0.35 L of a 3.5 M solution? A) 0.14 mL B) 0.90 mL C) 140 mL D) 900 mL

Q: 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

Q: Which atomic orbitals are involved in bonding and which as lone pair orbitals for N2H2? H "=" H 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

Q: What is the angle between adjacent sp3 hybrid orbitals? A) 90 B) 109.5 C) 120 D) 180

Q: The CO bond in COCl2 can be described asA) a bond and a bond, both involving sp hybrid orbitals on C.B) a bond involving an sp hybrid orbital on C and a bond involving a p orbital on C.C) a bond and a bond, both involving sp2 hybrid orbitals on C.D) a bond involving an sp2 hybrid orbital on C and a bond involving a p orbital on C.

Q: Which of the following would be expected to have sp2 hybridization on atom A? A) II B) I and III C) I, II, and III D) I and IV

Q: What orbital hybridization is expected for the central atom in a molecule with a trigonal planar geometry? A) sp B) sp2 C) sp3 D) None of the above

Q: The orbital hybridization on the carbon atom in HCN is A) sp. B) sp2. C) sp3. D) none of the above.

Q: A triple bond is generally composed ofA) three bonds.B) two bonds and one bond.C) one bond and two bonds.D) three bonds.

Q: Which of the following is not true? A) The sp3 hybrid orbitals are degenerate. B) An sp3 hybrid orbital may hold a lone pair of electrons. C) An sp3 hybrid orbital may form a sigma bond by overlap with an orbital on another atom. D) An sp3 hybrid orbital may form a pi bond by overlap with an orbital on another atom.

Q: Which orbital hybridization is associated with a tetrahedral charge cloud arrangement? A) sp B) sp2 C) sp3 D) None of the above

Q: The number of sp2 hybrid orbitals on the carbon atom in CO32" is A) one. B) two. C) three. D) four.

Q: A single sp3 hybrid orbital has A) one lobe. B) two lobes of equal size. C) two lobes of unequal size. D) four lobes of equal size.

Q: Which of the following is not a valence bond concept? A) The greater the overlap between the orbitals on two atoms, the stronger the bond. B) Lone pair electrons are in atomic orbitals or in hybrid atomic orbitals. C) Atomic orbitals on two atoms may overlap to form antibonding orbitals. D) A pair of electrons in a bond is shared by both atoms.

Q: The VSEPR model predicts the O"O"O bond angle in O3 to be A) 90. B) 109.5. C) less than 120 but greater than 109.5. D) 120.

Q: Arrange in order from the smallest to the largest bond angle: CH3+, NF3, NH4+, XeF4. A) CH3+, NF3, NH4+, XeF4 B) NF3, NH4+, XeF4, CH3+ C) XeF4, NH4+, NF3, CH3+ D) XeF4, NF3, NH4+, CH3+

Q: What is the smallest bond angle in SF6? A) 60 B) 90 C) 109.5 D) 120

Q: Which of the following best describes ICl2-? It has a molecular geometry that is A) linear molecular shape with no lone pairs on the I atom. B) linear molecular shape with lone pairs on the I atom. C) non-linear molecular shape with no lone pairs on the I atom. D) non-linear molecular shape with lone pairs on the I atom.

Q: What is the molecular geometry of IF5? A) octahedral B) seesaw C) square pyramidal D) trigonal bipyramidal

Q: What is the O-N-O bond angle in NO3-?A) less than 109.5B) 109.5C) 120D) greater than 120

Q: What is the molecular geometry of AsCl3? A) T-shaped B) tetrahedral C) trigonal planar D) trigonal pyramidal

Q: Which of the following should be nonlinear? A) only I B) only II C) only III D) II and III

Q: What is the molecular geometry of BrF4-? A) seesaw B) square planar C) square pyramidal D) tetrahedral

Q: Which of the following should be nonplanar? A) only I B) only II C) only III D) I and III

Q: Based on VSEPR theory, which should have the smallest XAX bond angle? A) B) C) D)

Q: What geometric arrangement of charge clouds is expected for an atom that has five charge clouds? A) tetrahedral B) square planar C) trigonal bipyramidal D) octahedral

Q: How many of the bonds in H2SO4 are coordinate covalent bonds?A) 0B) 2C) 4D) 6

Q: The carbon-carbon bond in C2H2 contains ________ and ________ bonds.