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Chemistry
Q:
The concentration of an aqueous solution of Fe2+ can be determined by a redox titration with aqueous bromate ion, BrO3-:6 Fe2+ (aq) + BrO3- (aq) + 6 H+ (aq) -> 6 Fe3+ (aq) + Br- (aq) + 3 H2O (l)Assume that the black spheres in the buret represent BrO3- ions, the gray spheres in the flask represent Fe2+ ions, the concentration of the BrO3- ions in the buret is 0.120 M, and the volumes in the buret and the flask are identical. What is the concentration of the Fe2+ in the flask, and what fraction of the BrO3- solution in the buret must be added to the flask to react with all the Fe2+ ions?A) 0.0200 M Fe2+; 1/18 of the BrO3- must be added.B) 0.0200 M Fe2+; 1/3 of the BrO3- must be added.C) 0.0400 M Fe2+; 1/18 of the BrO3- must be added.D) 0.0400 M Fe2+; 1/3 of the BrO3- must be added.
Q:
The concentration of an aqueous solution of I3- can be determined by a redox titration with aqueous sodium thiosulfate, Na2S2O3:2 S2O32- (aq) + I3- (aq) + -> S4O62- (aq) + 3 I- (aq)Assume that the black spheres in the buret represent S2O32- ions, the gray spheres in the flask represent I3- ions, the concentration of the S2O32- ions in the buret is 0.120 M, and the volumes in the buret and the flask are identical. What is the concentration of the I3- in the flask, and what fraction of the S2O32- solution in the buret must be added to the flask to react with all the I3- ions?A) 0.0400 M I3-; 1/3 of the S2O32- must be added.B) 0.0400 M I3-; 2/3 of the S2O32- must be added.C) 0.0600 M I3-; 1/3 of the S2O32- must be added.D) 0.0600 M I3-; 2/3 of the S2O32- must be added.
Q:
The concentration of an aqueous solution of NaOCl can be determined by a redox titration with iodide ion in acidic solution:OCl- (aq) + 2 I- (aq) + 2 H+ (aq) -> Cl- (aq) + I2 (aq) + H2O (l)Assume that the black spheres in the buret represent I- ions, the gray spheres in the flask represent OCl- ions, the concentration of the I- ions in the buret is 0.120 M, and the volumes in the buret and the flask are identical. What is the concentration of the NaOCl in the flask, and what fraction of the I- solution in the buret must be added to the flask to react with all the OCl- ions?A) 0.0400 M NaOCl; 1/3 of the I- must be added.B) 0.0400 M NaOCl; 2/3 of the I- must be added.C) 0.0600 M NaOCl; 1/3 of the I- must be added.D) 0.0600 M NaOCl; 2/3 of the I- must be added.
Q:
Which outcome corresponds to the reaction:H3AsO4 + 3 OH- -> 3 H2O + AsO43-?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the reaction:H2SO4 + 2 OH- -> 2 H2O + SO42-?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the reaction:HCN + OH- -> H2O + CN-?A) box (a)B) box (b)C) box (c)D) None of these
Q:
The following pictures represent aqueous solutions of three acids HA (A = X, Y, or Z), with water molecules omitted for clarity. Unshaded spheres represent hydrogen atoms or ions and gray spheres represent A atoms or ions. Which of the three is the strongest acid, and which is the weakest? A) HX is the strongest acid and HY is the weakest acid.
B) HY is the strongest acid and HX is the weakest acid.
C) HY is the strongest acid and HZ is the weakest acid.
D) HZ is the strongest acid and HY is the weakest acid.
Q:
Which outcome corresponds to the combination of silver and carbonate ions shown in the following equation?Ag+(aq) + CO32-(aq) -> ?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the combination of copper(II) and sulfide ions shown in the following equation?Cu2+(aq) + S2-(aq) -> ?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the mixing of sodium and sulfate ions shown in the following equation?2 Na+(aq) + SO42-(aq) -> ?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the combination of silver and chromate ions shown in the following equation?Ag+(aq) + CrO42-(aq) -> ?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the combination of calcium and carbonate ions shown in the following equation?Ca2+(aq) + CO32-(aq) -> ?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Which outcome corresponds to the mixing of potassium and sulfide ions shown in the following equation?2 K+(aq) + S2-(aq) -> ?A) box (a)B) box (b)C) box (c)D) None of these
Q:
Three different substances, A2X, A2Y, and A2Z, were dissolved in water with the following results. (Water molecules are omitted for clarity.) Which of the substances is the strongest electrolyte, and which is the weakest? A) A2X is the strongest electrolyte and A2Y is the weakest electrolyte.
B) A2Y is the strongest electrolyte and A2X is the weakest electrolyte.
C) A2Y is the strongest electrolyte and A2Z is the weakest electrolyte.
D) A2Z is the strongest electrolyte and A2Y is the weakest electrolyte.
Q:
Three different substances, A2X, A2Y, and A2Z, were dissolved in water with the following results. (Water molecules are omitted for clarity.) Which of the substances is the strongest electrolyte, and which is the weakest? A) A2X is the strongest electrolyte and A2Y is the weakest electrolyte.
B) A2Y is the strongest electrolyte and A2X is the weakest electrolyte.
C) A2Y is the strongest electrolyte and A2Z is the weakest electrolyte.
D) A2Z is the strongest electrolyte and A2Y is the weakest electrolyte.
Q:
Based on the balanced chemical equation shown below, determine the mass percent of Fe3+ in a 0.6450 gram sample of iron ore, if 22.40 mL of a 0.1000 M stannous chloride, SnCl2(aq), solution is required to completely react with the Fe3+ present in the ore sample. The chemical equation for the reaction is:2 Fe3+(aq) + Sn2+(aq) -> 2 Fe2+(aq) + Sn4+(aq).A) 6.196%B) 9.697%C) 19.40%D) 38.79%
Q:
Based on the balanced chemical equation shown below, determine the molarity of a solution containing Fe2+(aq), if 40.00 mL of the Fe2+(aq) solution is required to completely react with 30.00 mL of a 0.125 M potassium bromate, KBrO3(aq), solution.The chemical equation for the reaction is:6 Fe2+(aq) + BrO3-(aq) + 6 H+(aq) -> 6 Fe3+(aq) + Br-(aq) + 3 H2O(l).A) 0.0156 MB) 0.0938 MC) 0.562 MD) 1.00 M
Q:
What is the molarity of a potassium triiodide solution, KI3(aq), if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution, Na2S2O3(aq)? The chemical equation for the reaction is:2 S2O32-(aq) + I3-(aq) -> S4O62-(aq) + 3 I-(aq)A) 0.0833 MB) 0.120 MC) 0.167 MD) 0.333 M
Q:
Based on the balanced chemical equation shown below, what volume of 0.250 M K2S2O3(aq) is needed to completely react with 12.44 mL of 0.125 M KI3(aq)?2 S2O32-(aq) + I3-(aq) -> S4O62-(aq) + 3 I-(aq)A) 3.11 mLB) 6.22 mLC) 12.4 mLD) 49.8 mL
Q:
According to the balanced chemical equation5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) -> 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)0.3500 grams of oxalic acid, H2C2O4 will react with ________ mL of 0.100 M potassium permanganate, KMnO4 solution.A) 15.5 mLB) 38.9 mLC) 77.7 mLD) 97.2 mL
Q:
According to the balanced chemical equation5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) -> 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)0.3500 grams of oxalic acid, H2C2O4 will react with ________ moles of permanganate, MnO4-.A) 0.001554B) 0.003887C) 0.007774D) 0.009718
Q:
According to the balanced equation shown below, 1.00 mole of oxalic acid, H2C2O4, reacts with ________ moles of permanganate ion, MnO4-.5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) -> 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)A) 0.400B) 1.00C) 2.00D) 2.25
Q:
What is the reduction half reaction for the following chemical reaction in a basic solution?ClO-(aq) + Cr(OH)4-(aq) -> CrO42-(aq) + Cl-(aq)A) ClO-(aq) + 2 H+(aq) + 2e- -> Cl-(aq) + H2O(l)B) ClO-(aq) + H2O(l) + 2e- -> Cl-(aq) + 2 OH-(aq)C) Cr(OH)4-(aq) + 4 OH-(aq) -> CrO42-(aq) + 4 H2O(l) + 3e-D) Cr(OH)4-(aq) -> CrO42-(aq) + 4 H+(aq) + 3e-
Q:
What is the reduction half reaction for the following chemical reaction in a basic solution?Mn2+(aq) + 2 ClO3-(aq) + OH-(aq) -> MnO2(s) + 2 ClO2(aq) + H2O(l)A) Mn2+(aq) + 4 OH-(aq) -> MnO2(s) + 2 H2O(l) + 2e-B) Mn2+(aq) + 2 H2O(l) -> MnO2(s) + 4 H+(aq) + 2e-C) ClO3-(aq) + H2O(l) + e- -> ClO2(aq) + 2 OH-(aq)D) ClO3-(aq) + 2 H+(aq) + e- -> ClO2(aq) + H2O(l)
Q:
What is the oxidation half reaction in the following chemical reaction?Cr2O72-(aq) + 6 Cl-(aq) + 14 H+(aq) -> 2 Cr3+(aq) + 3 Cl2(aq) + 7 H2O(l)A) Cr2O72-(aq) + 14 H+(aq) + 6e- -> 2 Cr3+(aq) + 7 H2O(l)B) Cr2O72-(aq) + 14 H+(aq) -> 2 Cr3+(aq) + 7 H2O(l) + 6e-C) 2 Cl-(aq) -> Cl2(aq) + 2e-D) Cl2(aq) + 2e- -> 2 Cl-(aq)
Q:
What is the oxidation half reaction in the following chemical reaction?Zn(s) + 2 H+(aq) -> Zn2+(aq) + H2(g)A) Zn(s) -> Zn2+(aq) + 2e-B) Zn2+(aq) + 2e- -> Zn(s)C) 2 H+(aq) + 2e- -> H2(g)D) H2(g) -> 2 H+(aq) + 2e-
Q:
Determine the number of water molecules necessary to balance the reduction half reaction of____ ClO3-(aq) -> ____ Cl- (aq)that occurs in an acidic solution.A) 1B) 3C) 5D) 7
Q:
Determine the number of water molecules necessary to balance the reduction half reaction of____ MnO4-(aq) -> ____ Mn2+(aq)that occurs in an acidic solution.A) 2B) 4C) 5D) 7
Q:
Determine the number of water molecules necessary to balance the reduction half reaction of____ MnO4-(aq) -> ____ MnO2(s) that occurs in a basic solution.A) 2B) 3C) 4D) 5
Q:
Determine the number of water molecules necessary to balance the following chemical equation.Cr2O72-(aq) + Cl-(aq) + H+(aq) -> Cr3+(aq) + Cl2(g) + _____ H2O(l)A) 3B) 5C) 7D) 14
Q:
What are the coefficients in front of BrO3-(aq) and Br-(aq) when the following equation is balanced in an acidic solution?_____ BrO3-(aq) + _____ Br-(aq) -> _____ Br2(aq)A) 1, 3B) 1, 5C) 2, 3D) 2, 5
Q:
What are the coefficients in front of Fe(s) and O3(g) when the following equation is balanced in a basic solution?_____ Fe(s) + _____ O3(g) -> _____ Fe2O3(s) + _____ O2(g)A) 2, 2B) 2, 3C) 3, 2D) 3, 4
Q:
What are the coefficients in front of NO3-(aq) and Zn(s) when the following equation is balanced in a basic solution?_____ NO3-(aq) + _____ Zn(s) -> _____ Zn2+(aq) + _____ NO(g)A) 2, 3B) 2, 5C) 3, 2D) 3, 4
Q:
What is true when the following equation is balanced in basic solution?P(s) + PO43-(aq) -> HPO32-(aq)A) H+ appears on the left side of the equation.B) H+ appears on the right side of the equation.C) OH- appears on the left side of the equation.D) OH- appears on the right side of the equation.
Q:
What are the coefficients in front of NO3-(aq) and Cu(s) when the following redox equation is balanced in an acidic solution?_____ NO3-(aq) + _____ Cu(s) -> _____ NO(g) + _____ Cu2+(aq)A) 2, 3B) 2, 6C) 3, 4D) 3, 6
Q:
In the unbalanced equation shown below how many moles of electrons are transferred per mole of reducing agent?C2O42- (aq) + MnO4-(aq) -> CO2(aq) + Mn2+(aq)A) 1B) 2C) 5D) 10
Q:
Which elements will not react with liquid water or with aqueous H+ ions?
A) Ag, Au, Hg, Pt
B) Ba, Ca, Li, K
C) Co, Cu, Ni, Sn
D) Cr, Fe, Mn, Zn
Q:
Which elements will not react with liquid water but will react with aqueous H+ ions?
A) Ag, Cu, Hg, Pt
B) Al, Cr, Mn, Zn
C) Ba, Ca, Li, Na
D) Ag, Au, Ca, K
Q:
How many chloride ions are in 1.50 mol of aluminum chloride?
A) 3.00 chloride ions
B) 4.50 chloride ions
C) 9.03 1023 chloride ions
D) 2.71 1024 chloride ions
Q:
What mass of sulfur hexafluoride, SF6, has the same number of fluorine atoms as 25.0 g of oxygen difluoride, OF2?
A) 0.901 g
B) 8.33 g
C) 22.5 g
D) 203 g
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 μg?
A) 58.0 g/mol
B) 172 g/mol
C) 232 g/mol
D) 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:
Which contains Avogadro's number of formula units?
A) 36.5 g of Cl
B) 36.5 g of Cl2
C) 36.5 g of HCl
D) All of these
Q:
Which is a formula mass?
A) 1.0 amu of H
B) 2.0 amu of H2
C) 24.0 amu of NaH
D) All of these
Q:
Which represents one formula unit?
A) One H
B) One H2
C) One NaH
D) All of these
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 these
Q:
Which conducts electricity?
A) A large collection of iron atoms
B) A single iron atom
C) Both a large collection of iron atoms and a single iron atom
D) Neither a large collection of iron atoms nor a single iron atom
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 these are true.
Q:
Given the chemical equation: N2 + 3 H2 -> 2 NH3. On a molecular 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:
Chemical equations are balanced in order to obey the law of
A) definite proportions.
B) mass action.
C) mass conservation.
D) multiple proportions.
Q:
Analysis of a 1.000-g sample of the oral hypoglycemic agent metformintm yielded 0.3720 g
of carbon, 0.0858 g of hydrogen, and 0.5422 g of nitrogen. Metformintm has a molar mass of
129.16 g/mol. What is the molar mass of Metformintm?
Q:
The empirical formula of a compound that contains 82.66% carbon and 17.34% hydrogen is ________.
Q:
What is the empirical formula of benzene, C6H6?
Q:
The number of milliliters of 0.250 M HCl required to react with 50.00 mL of 0.450 M KOH in the reaction shown below is ________.HCl + KOH -> H2O + KCl
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:
The number of milliliters of 12.0 M HCl required to prepare 250 mL of 0.500 M HCl is ________.
Q:
The number of grams of NaCl required to prepare 500 mL of 0.100 M NaCl is ________.
Q:
The number of moles of CaCl2 in 25.0 mL of 0.222 M CaCl2 is ________.
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:
Hydrazine, N2H4, is used as a rocket fuel. In the reaction below, if 80.1 g of N2H4 and 92.0 g of N2O4 are allowed to react, which is the limiting reactant, and how many grams of excess reactant remain at the end of the reaction?2 N2H4 + N2O4 -> 3 N2 + 4 H2O
Q:
When carbon dioxide dissolves in water, H+ is formed, which makes the solution acidic, as shown in the balanced equation below.CO2 + H2O -> HCO3- + H+What is the percent yield if 0.0088 g of CO2 reacts with 900 g of H2O to form 0.000108 g of H+?