Exam 3: Solutions & Solubility
38-40. Household bleach is an aqueous sodium hypochlorite solution that is 5.00% sodium hypochlorite by mass. (Given: density of bleach = 1.00g/ml) 39. For every 100.0 g of bleach, what is the molar concentration, M? 0.408 0.672 0.553 0.470
0.672
When sodium bicarbonate mixes with acetic acid, which of the following reactions occurs? 1 NaHCO3 + 1 CH3CO2H → 1 NaCH3CO2 + 1 H2O + 1 CO2 1 NaHCO3 + 1 CH3CO2H → 1 NaOH + 2 H2 + 2 CO2 1 NaHCO3 + 1 CH3CO2H → 1 NaOH + 2 CO2 + 1 CH4 1 NaHCO3 + 2 CH3CO2H → 1 NaOH + 3 CO2 + C2H8
1 NaHCO3 + 1 CH3CO2H → 1 NaCH3CO2 + 1 H2O + 1 CO2
Using the correct number of significant figures, what is the answer to 3.4562 + 9.58 g? 13.036 13.04 13.0362 13.0
13.04
41-44. A precipitate forms when an aqueous solution of 1.5L of a 2.0M copper (I) nitrate is added to an aqueous solution of 2.0L of 1.5M potassium carbonate. The unbalanced equation is given below: ___CuNO3 (aq) + ___K2CO3 (aq) → ___Cu2CO3 (s) + ___KNO3 (aq) 42. Determine the theoretical yield of copper (I) carbonate (MW = 124 g/mole). 248 g 186 g 372 g 62 g
186 g
Using the correct number of significant figures, what is the answer when 6.51 is divided by 0.034? 190 192 200 191.5
190
Determine the number of moles in 100.0 g of carbon dioxide, CO2. 1.368 x 1024 2.273 0.4401 44.01
2.273
Which of the following numbers has 5 significant figures? 0.3080 200.01 0.0160 0.0455
200.01
41-44. A precipitate forms when an aqueous solution of 1.5L of a 2.0M copper (I) nitrate is added to an aqueous solution of 2.0L of 1.5M potassium carbonate. The unbalanced equation is given below: ___CuNO3 (aq) + ___K2CO3 (aq) → ___Cu2CO3 (s) + ___KNO3 (aq) 43. What is the percent yield if 50 g of copper (II) carbonate is actually formed. 27% 80% 13% 20%
27%
41-44. A precipitate forms when an aqueous solution of 1.5L of a 2.0M copper (I) nitrate is added to an aqueous solution of 2.0L of 1.5M potassium carbonate. The unbalanced equation is given below: ___CuNO3 (aq) + ___K2CO3 (aq) → ___Cu2CO3 (s) + ___KNO3 (aq) Determine the number of moles reacting of the limiting reactant, theoretical yield, percent yield and whether the resulting solution is acidic, basic or neutral. 41. Determine the number of moles reacting of the limiting reactant. 3.0 moles CuNO3 1.5 moles K2CO3 2.0 moles CuNO3 3.0 moles K2CO3
3.0 moles CuNO3
35-37. Using the half-cell method, balance the following unbalanced acidic redox reaction. Fe 2+ (aq) + MnO4- (aq) → Fe3+ (aq) + Mn2+ (aq) 37. The balanced redox reaction can be written as: 3 Fe2+ (aq) + MnO4- (aq) + 8 H+ (aq) → 3 Fe3+ (aq) + Mn2+ (aq) + 4 H2O (l) 5 Fe2+ (aq) + MnO4- (aq) + 8 H+ (aq) → 5 Fe3+ (aq) + Mn2+ (aq) + 4 H2O (l) 3 Fe2+ (aq) + 2MnO4- (aq) + 16 H+ (aq) → 3 Fe3+ (aq) + 2Mn2+ (aq) + 8 H2O (l) 5 Fe2+ (aq) + MnO4- (aq) + 4 H+ (aq) → 5 Fe3+ (aq) + Mn2+ (aq) + 2 H2O (l)
5 Fe2+ (aq) + MnO4- (aq) + 8 H+ (aq) → 5 Fe3+ (aq) + Mn2+ (aq) + 4 H2O (l)
How many significant figures are there in the number 0.0210060? 3 8 6 7
6
What type of reaction occurs when the following compounds are combined in an aqueous solution? NH4Cl + KOH → neutralization oxidation / reduction gas evolution precipitation
? no answer
Which of the following is a quantitative observation? Algebra can be used to solve for the concentration of a solution. Copper has a lower thermal conductivity than silver. A 3M HCl soln was prepared by adding 2.5 L of concentrated HCl to 7.5 L of water. In acid rain, nitrogen dioxide reacts with a hydroxide ion to form nitric acid
A 3M HCl soln was prepared by adding 2.5 L of concentrated HCl to 7.5 L of water.
Which of the following does NOT indicate that a chemical change has occurred? A substance goes from a vapor state to a liquid state when cooled. The color of the solution changes from peach to blood red. The substance gets "hot" without heat being added. The solution begins to bubble spontaneously.
A substance goes from a vapor state to a liquid state when cooled.
Which of the following reactions is NOT an oxidation-reduction reaction? Ag+ (aq) + Cl- (aq) → AgCl (s) 2 HgO (s) → 2 Hg (l) + O2 (g) 4 Fe (s) + 3 O2 (g) → 2 Fe2O3 (s) + 2 CuBr2 (s) → 2 CuBr (s) + Br2 (l)
Ag+ (aq) + Cl- (aq) → AgCl (s)
Refer to Handout provided. D - colorless solution, pH = 4, flame color = none D-F = white ppt D-E = yellow ppt D-C = dark red ppt D-B = white ppt D-A = no reaction NiSO4 Na2CrO4 Pb(CH3COO)2 FeBr3 BaCl2 AgNO3
AgNO3
Assign whether the species in water would be acidic, basic, or of a neutral pH; a strong, weak, or non-electrolyte. copper (II) sulfate / CuSO4 a.) acidic, basic or neutral b.) strong electrolyte, weak electrolyte or nonelectrolyte
Answer 1: acid Answer 2: strong electrolyte
Assign whether the species in water would be an acid, base, or of neutral pH; a strong, weak, or non-electrolyte. nitrous acid, HNO2 a.) acidic, basic or neutral acidic b.) strong electrolyte, weak electrolyte or nonelectrolyte weak electrolyte
Answer 1: acidic Answer 2: weak electrolyte
Assign whether the species in water would be an acid, base, or of neutral pH; a strong, weak, or non-electrolyte. calcium oxide / CaO a.) acidic, basic or neutral basic b.) strong electrolyte, weak electrolyte or nonelectrolyte strong electrolyte
Answer 1: basic Answer 2: strong electrolyte
Assign whether the species in water would be an acid, base, or of neutral pH; a strong, weak, or non-electrolyte. ammonium hydroxide, NH3OH a.) acidic, basic or neutral basic b.) strong electrolyte, weak electrolyte or nonelectrolyte weak electrolyte
Answer 1: basic Answer 2: weak electrolyte
Assign whether the species in water would be acidic, basic, or of a neutral pH; a strong, weak, or non-electrolyte. benzaldehyde / C7H6O a.) acidic, basic or neutral b.) strong electrolyte, weak electrolyte or nonelectrolyte
Answer 1: neutral Answer 2: non-electrolyte
Refer to Handout provided. B - colorless solution, pH = 3, flame color = green B-F = white ppt B-E = no reaction B-D = white ppt B-C = yellow ppt B-A = white ppt Na2CrO4 AgNO3 BaCl2 NiSO4 Pb(CH3COO)2
BaCl2
Using your knowledge of the rules of solubility, Pb(CH3CO2)2 (lead (II) acetate) reacts with all of the following except which one to form a precipitate? K2C2O4 Na2SO4 Cu(NO3)2 Na2S
Cu(NO3)2
Which of the following IS a physical property? Alkaline earth oxides that dissolve form basic solutions. Oxygen reacts with hydrogen to produce water. Corrosion is caused by a redox reaction between iron and oxygen. Diatomic oxygen has a mass of 32 g/mole.
Diatomic oxygen has a mass of 32 g/mole.
Refer to Handout provided. E - maroon solution, pH = 1, flame color = yellow E-F = yellow solution E-D = yellow ppt E-C = yellow ppt E-B = no reaction E-A = white ppt BaCl2 Pb(CH3COO)2 Na2CrO4 NiSO4 FeBr3 AgNO3
FeBr3
Which of the following is a qualitative observation? Fluorine is the most electronegative element. Fluorine reacts in a two to one ratio with calcium. At 25 oC, fluorine is a diatomic gas. Fluorine has a molar mass of 18.998g.
Fluorine is the most electronegative element.
41-44. A precipitate forms when an aqueous solution of 1.5L of a 2.0M copper (I) nitrate is added to an aqueous solution of 2.0L of 1.5M potassium carbonate. The unbalanced equation is given below: ___CuNO3 (aq) + ___K2CO3 (aq) → ___Cu2CO3 (s) + ___KNO3 (aq) 44. Separately the reactants fully dissociate in water to form an acidic and a basic solution. When combined they will neutralize each other. What is the excess reagent and will the remaining solution be acidic or basic? CuNO3 basic K2CO3 basic neutral - they are in a 1:1 mole ratio K2CO3 acidic CuNO3 acidic
K2CO3 basic
38-40. Household bleach is an aqueous sodium hypochlorite solution that is 5.00% sodium hypochlorite by mass. (Given: density of bleach = 1.00g/ml) 40. A diluted bleach solution is prepared for the disinfection of potable water storage containers by adding 350 ml of bleach into 10.0 L of water. What is the molar concentration, M, of the solution used for disinfection? 0.227 0.0235 0.0175 2.12
NOT: 0.0175
If 20.0 ml of 0.500 M HCl is required to completely neutralize 15.0 ml of KOH, what is the concentration in M of KOH? 0.667 0.375 0.002 0.500
NOT: 0.375
Determine the number of moles in 85.0 ml of a 1.00 M aqueous solution of potassium bromide, KBr. 11.8 119 0.170 0.0850
NOT: 11.8
Determine the net ionic equation for the following aqueous reaction: SnCl2 + Na2S → Sn4+ + Cl2- → SnCl2 2 Na+ + S2 - → Na2S Sn2+ + S2- → SnS 2 Na+ + 2 Cl- → NaCl
NOT: 2 Na+ + 2 Cl- → NaCl
Determine the net ionic equation for the following aqueous reaction: H2SO4(aq) + 2NaOH(aq) → SO4 2- → S2- + 2 O2 2 H+ + 2 OH- → 2 H2O 2 Na+ + SO4 2- → Na2SO4 S2- + 2H+ → H2S
NOT: 2 Na+ + SO4 2- → Na2SO4
What is the numerical value of 2.000 x 102 ? 0.0200 200 0.02 200.0
NOT: 200
Determine the new concentration in M (moles per liter) of the solution when 25.0 ml of 1.43M HCl is diluted to 500.0 ml. 0.715 0.0350 28.6 8.74
NOT: 28.6
Benzene (C6H6) has a density of 0.8765 g/ml. How many milliliters of benzene would correspond to 186.2 g? 78.11 212.4 163.2 0.004707
NOT: 78.11
Which of the following IS a chemical property? A copper wire conducts an electric current. Benzene (C6H6) can be burned in the presence of oxygen to form carbon dioxide and water. Water vaporizes at 100oC to form a gas. Glass, sand and quartz are all forms of silicon dioxide.
NOT: A copper wire conducts an electric current.
Determine the net ionic reaction for the following aqueous reaction: NH4Cl + KOH → H+ + OH- → H2O NH4+ + OH- → NH4OH NH4+ + OH- → NH3 + H2O Cl- + K+ → KCl
NOT: Cl- + K+ → KCl
For the following aqueous reaction, identify the spectator ions: 3 Fe(NO3)2 + 2 Na3PO4 → Fe3(PO4)2 + 6 NaNO3 Fe2+ : NO3- Na+ : PO4 3- Na+ : NO3- Fe2+ : PO4 3-
NOT: Fe2+ : PO4 3-
35-37. Using the half-cell method, balance the following unbalanced acidic redox reaction. Fe 2+ (aq) + MnO4- (aq) → Fe3+ (aq) + Mn2+ (aq) 35. The reduction half-cell can be written as: MnO4- + 8 H+ + 6 e- → Mn2+ + 4 H2O Fe2+ → Fe3+ + 2 e- MnO4- + 8 H+ + 5 e- → Mn2+ + 4 H2O Fe2+ → Fe3+ + e-
NOT: Fe2+ → Fe3+ + 2 e-
35-37. Using the half-cell method, balance the following unbalanced acidic redox reaction. Fe 2+ (aq) + MnO4- (aq) → Fe3+ (aq) + Mn2+ (aq) 36. The oxidation half-cell can be written as: Fe2+ → Fe3+ + e- MnO4- + 8 H+ + 6 e- → Mn2+ + 4 H2O MnO4- + 8 H+ + 5 e- → Mn2+ + 4 H2O Fe2+ → Fe3+ + 2 e-
NOT: MnO4- + 8 H+ + 6 e- → Mn2+ + 4 H2O
Refer to Handout provided. C - yellow solution, pH = 2, flame color = yellow C-F = dark red ppt C-E = yellow ppt C-D = dark red ppt C-B = yellow ppt C-A = yellow ppt Na2CrO4 BaCl2 FeBr3 Pb(CH3COO)2 NiSO4 AgNO3
Na2CrO4
38-40. Household bleach is an aqueous sodium hypochlorite solution that is 5.00% sodium hypochlorite by mass. (Given: density of bleach = 1.00g/ml) 38. What is the chemical formula for sodium hypochlorite? NaClO NaClO2 NaClO3 NaClO4
NaClO
Refer to Handout provided. F - green solution, pH = 2, flame color = no change F-E = yellow solution F-D = white ppt F-C = dark red ppt F-B = white ppt F-A = white ppt AgNO3 NiSO4 Na2CrO4 FeBr3 BaCl2 Pb(CH3COO)2
NiSO4
Oxidation numbers often appear to have the same value as the ionic charge on a species. However, there are a few exceptions, one of which is hydrogen peroxide, H2O2. What is the general rule and the exception in the case of hydrogen peroxide? Oxidation number for oxygen is normally -2, here it is -1. Oxidation number for oxygen is normally -1, here it is -2. Oxidation number for hydrogen is normally +1, here it is -1. Oxidation number of hydrogen is normally +1, here it is +2.
Oxidation number for oxygen is normally -2, here it is -1.
Refer to Handout provided. A - colorless solution, pH = 7, flame color = green A-F = white ppt A-E = white ppt A-D = no reaction A-C = yellow ppt A-B = white ppt FeBr3 NiSO4 AgNO3 Pb(CH3COO)2 Na2CrO4 BaCl2
Pb(CH3COO)2
When disposing of chemicals in a waste container, Becca notices a smelly plume of gas over it. What is the most likely cause of the gas generated from the solution? Copper nitrate reacting with hydrochloric acid to form hydrogen gas. Sodium sulfide reacting with sulfuric acid to generate hydrogen sulfide gas. Potassium nitrate reacting exothermically with an aqueous sodium chloride solution to generate water vapor. Calcium carbonate reacting with hydrochloric acid to generate carbon dioxide gas.
Sodium sulfide reacting with sulfuric acid to generate hydrogen sulfide gas.
Which of the following observations indicate a reaction has occurred? all of the other answers color change gas evolution (i.e., bubbles form) precipitate formation
all of the other answers
For which type of reaction would Litmus paper be the most useful? neutralization precipitation oxidation - reduction gas evolution
neutralization
What type of reaction occurs when the following compounds are combined? H2SO4 (aq) + 2 NaOH (aq) → gas evolution precipitation oxidation-reduction neutralization
neutralization
What type of reaction occurs when the following compounds are combined in an aqueous solution? SnCl2 + Na2S → neutralization precipitation gas evolution oxidation-reduction
precipitation
