ScienceChemistryCH17 – Mastering Chemistry – Alaa Hashim
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CH17 - Mastering Chemistry - Alaa Hashim

Luka Rivera avatar Luka Rivera
25 July 2022
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49 test answers

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question
Which of the following actions would shift this reaction toward solid lead chloride?
answer
Add more chloride ions.
question
In which of the following would lead chloride be least soluble?
answer
1 M KCl
question
In which of the following would lead chloride be most soluble?
answer
1 M KNO3
question
Which action would shift this reaction away from solid lead chloride and toward the dissolved ions?
answer
removing chloride ions
question
AgI, BaF2, and AgBr are all sparingly soluble salts. Which of these salts will be more soluble in an acidic solution than in water?
answer
BaF2
question
As a chemist for an agricultural products company, you have just developed a new herbicide,"Herbigon," that you think has the potential to kill weeds effectively. A sparingly soluble salt, Herbigon is dissolved in 1 M acetic acid for technical reasons having to do with its production. You have determined that the solubility product Ksp of Herbigon is 8.50×10−6. Although the formula of this new chemical is a trade secret, it can be revealed that the formula for Herbigon is X-acetate (XCH3COO, where "X" represents the top-secret cation of the salt). It is this cation that kills weeds. Since it is critical to have Herbigon dissolved (it won't kill weeds as a suspension), you are working on adjusting the pH so Herbigon will be soluble at the concentration needed to kill weeds. What pH must the solution have to yield a solution in which the concentration of X+ is 5.50×10−3 M ? The pKa of acetic acid is 4.76.
answer
pH = 1.95
question
In which solution is AgCl most soluble?
answer
in a solution that is 0.20 M in KNO3
question
Use the molar solubility 1.08×10−5M in pure water to calculate Ksp for BaCrO4.
answer
Ksp = 1.17×10−10
question
Part complete Use the molar solubility 1.55×10−5M in pure water to calculate Ksp for Ag2SO3.
answer
Ksp = 1.49×10−14
question
Part complete Use the molar solubility 2.22×10−8M in pure water to calculate Ksp for Pd(SCN)2.
answer
Ksp = 4.38×10−23
question
Consider the compounds with the generic formulas listed below and their corresponding molar solubilities in pure water. AX2 ;molarsolubility= 1.75×10−4 M A2X ;molarsolubility= 2.25×10−4 M AX ;molarsolubility= 1.25×10−6 M Which compound will have the smallest value of Ksp?
answer
AX
question
What is the value of Q when the solution contains 2.00×10−2 M Ca2+ and 3.00×10−2M CrO42−? Express your answer numerically.
answer
Q = 6.00×10−4
question
Calcium chromate, CaCrO4, has a Ksp value of 7.10×10−4 . What happens when calcium and chromate solutions are mixed to give 2.00×10−2 M Ca2+ and 3.00×10−2 M CrO42−?
answer
No precipitate forms because Q
question
What concentration of the lead ion, Pb2+, must be exceeded to precipitate PbBr2 from a solution that is 1.00×10−2 M in the bromide ion, Br−? Ksp for lead(II) bromide is 4.67×10−6 .
answer
4.67×10−2 M
question
If 500.0 mL of 0.10 M Ca2+ is mixed with 500.0 mL of 0.10 M SO42−, what mass of calcium sulfate will precipitate? Ksp for CaSO4 is 2.40×10−5. Express your answer to three significant figures and include the appropriate units.
answer
6.14 g
question
A solution contains some or all of the ions Cu2+, Al3+, K+, Ca2+, Ba2+, Pb2+, and NH4+. The following tests were performed, in order, on the solution. Addition of 6 M HCl produced no reaction. Addition of H2S with 0.2 M HCl produced a black solid. Addition of (NH4)2S produced a white solid. Addition of (NH4)2HPO4 in NH3 produced no reaction. The final supernatant when heated produced a purple flame. Identify which of these ions were present in the solution, which were absent, and for which ones no conclusions can be drawn. Drag the appropriate items to their respective bins.
answer
PRESENT - CU^2+ , AL^3+, K^+ ABSENT - Pb^2+ , Ca ^2+ , K^+ INCONCLUSIVE - NH4^+
question
Select the reagent that will separate the pairs of ions listed. Drag each label to the appropriate target.
answer
Ions : Reagent Ag+ and Al^3+ : 6M HCL Cu^2+ and Ca^2+ : H2S, 0.2 M HCL Mg^2+ and K+ : (NH4)2 HPO4 in NH3 Ni^2+ and Co^2+ : Cannot be separated
question
Gives what happens at low pH for aluminum hydroxide.
answer
Al(H2O)6 3+ dissolves
question
What happens to the entropy of a sample of matter when it changes state from a solid to a liquid?
answer
increase
question
What happens to the entropy of a sample of matter when it changes state from a liquid to a gas?
answer
increase
question
ΔH negative, ΔS positive
answer
The reaction will be spontaneous at all temperatures.
question
ΔH positive, ΔS negative
answer
The reaction will be nonspontaneous at all temperatures.
question
ΔH negative, ΔS negative
answer
The reaction will be spontaneous at low temperature, but nonspontaneous at high temperature.
question
ΔH positive, ΔS positive
answer
The reaction will be nonspontaneous at low temperature, but spontaneous at high temperature.
question
Predict the sign of the entropy change, ΔS∘, for each of the reaction displayed. Drag the appropriate items to their respective bins.
answer
Positive: CH3OH(l)→CH3OH(g) 2NO2(g)→N2(g)+2O2(g) Ca(OH)2(s)→CaO(s)+H2O(g) C7H16(g)+11O2(g)→7CO2(g)+8H2O(g) Negative: 2Mg(s)+O2(g)→2MgO(s) Ba2+(aq)+SO42−(aq)→BaSO4(s)
question
Calculate the standard entropy change for the reaction 2Mg(s)+O2(g)→2MgO(s) using the data from the following table: Substance ΔH∘f (kJ/mol) ΔG∘f (kJ/mol) S∘ [J/(K⋅mol)] Mg(s) 0.00 0.00 32.70 O2(g) 0.00 0.00 205.0 MgO(s) -602.0 -569.6 27.00
answer
ΔS∘ = -216.4 JK
question
How do you calculate the change in free energy for a reaction under nonstandard conditions?
answer
ΔGrnx=ΔG∘rnx+RTlnQ
question
Which of the following is true?
answer
The spontaneity of a reaction is not necessarily related to the speed of a reaction.
question
In which of the following reactions will the entropy change, ΔS, be a positive value? Check all that apply.
answer
Co(NH3)4(acac)3+(aq)+2acac(aq)⇌Co(acac)33+(aq)+3NH3(aq) FeCl64−(aq)+EDTA4−(aq)⇌FeEDTA2−(aq)+6Cl−(aq)
question
Part complete Consider the reaction of a generic metal ion (Mn+) with a generic porphine molecule (por): M(H2O)mn+(aq)+por(aq)⇌M(por)n+(aq)+mH2O(l) Based on the values of standard enthalpy, ΔH∘, and entropy, ΔS∘, shown here, ΔH∘ ΔS∘ -13.5 kJ 9.32 J/K what is the value of the formation constant, Kf , for the reaction at 25 ∘C? Express your answer numerically.
answer
Kf = 713
question
The ________ Law of Thermodynamics states the energy is conserved in chemical processes.
answer
first
question
In which of the following processes do the molecules become more orderly?
answer
water freezing
question
________ is a thermodynamic function that increases with the number of energetically equivalent ways to arrange components of a system to achieve a particular state.
answer
Entropy
question
Which of the following processes have a ΔS > 0?
answer
CH4(g) + H2O(g) → CO(g) + 3 H2(g)
question
The ________ Law of Thermodynamics states that for any spontaneous reaction, the entropy of the universe increases.
answer
Second
question
Part complete Identify the change in state that does not have an increase in entropy.
answer
water freezing
question
Which of the following processes have a ΔS < 0?
answer
carbon dioxide(g) → carbon dioxide(s) propanol (g, at 555 K) → propanol (g, at 400 K) water freezes methyl alcohol condenses All of the above processes have a ΔS < 0.**********
question
Why does the entropy of a gas increase when it expands into a vacuum?
answer
The entropy of a gas increases when it expands into a vacuum because the number of possible states increases .
question
2KClO3(s)→2KCl(s)+3O2(g)
answer
ΔSsys>0
question
CH≡CH(g)+H2(g)→CH2=CH2(g)
answer
ΔSsys<0
question
Na(s)+1/2Cl2(g)→NaCl(s)
answer
ΔSsys<0
question
N2(g)+3H2(g)→2NH3(g)
answer
ΔSsys<0
question
ΔH∘rxn= 85 kJ , ΔSrxn= 141 J/K , T= 290 K Express your answer using two significant figures.
answer
ΔSuniv = -150 J/K
question
ΔH∘rxn= 85 kJ , ΔSrxn= 141 J/K , T= 761 K Express your answer using one significant figure. Predict whether or not the reaction in part B will be spontaneous. - spontaneous*****
answer
ΔSuniv = 30 J/K
question
ΔH∘rxn= 85 kJ , ΔSrxn=− 141 J/K , T= 290 K Express your answer using two significant figures. Predict whether or not the reaction in part C will be spontaneous. - non spontaneous
answer
ΔSuniv = -430 J/K
question
ΔH∘rxn=− 85 kJ , ΔSrxn= 141 J/K , T= 391 K Express your answer using two significant figures. Predict whether or not the reaction in part D will be spontaneous. - spontaneous
answer
ΔSuniv = 360 J/K
question
Predict whether or not the reaction in part A will be spontaneous. Part A) Part complete ΔH∘rxn= 85 kJ , ΔSrxn= 141 J/K , T= 290 K Express your answer using two significant figures. ΔSuniv = -150 J/K
answer
non spontaneous
question
Consider a reaction that has a negative ΔH and a positive ΔS. Which of the following statements is TRUE?
answer
This reaction will be spontaneous at all temperatures.
question
How can you calculate the standard entropy change for a reaction from tables of standard entropies?
answer
ΔSornx=∑npSo(products)−∑nrSo(reactants)