C2H5NH2
Express your answer as a chemical formula.
answer
C2H5NH3+
question
ClO4β
Express your answer as a chemical formula.
answer
HClO4
question
HPO42β
Express your answer as a chemical formula.
answer
H2PO4β
question
HCO3β
Express your answer as a chemical formula.
answer
H2CO3
question
Classify each of the following acids as strong or weak.
HF
answer
Weak
question
HCHO2
answer
weak
question
H2SO4
answer
strong
question
H2CO3
answer
weak
question
Write an expression for the acid ionization constant (Ka) for HCHO2.
answer
Ka=[H3O+][CHO2β]/[HCHO2]
question
Write an expression for the acid ionization constant (Ka) for HF.
answer
Ka=[H3O+][Fβ]/[HF]
question
Write an expression for the acid ionization constant (Ka) for H2CO3.
answer
Ka=[H3O+][HCOβ3]/[H2CO3]
question
Consider the given acid ionization constants. Identify the strongest conjugate base.
Acid Ka
HNO2(aq) 4.6Γ10β4
HCHO2(aq) 1.8Γ10β4
HClO(aq) 2.9Γ10β8
HCN(aq) 4.9Γ10β10
answer
CNβ(aq)
question
What is the pH of a solution whose hydroxide ion concentration, [OH-], is 4.3 Γ 10-4 M?
answer
10.63
question
What is the H+ concentration for an aqueous solution with pOH = 3.58 at 25 βC?
Express your answer to two significant figures and include the appropriate units.
answer
[H+] =
3.8Γ10β11 M
question
Arrange the following aqueous solutions, all at 25 βC, in order of decreasing acidity.
Rank from most acidic to most basic. To rank items as equivalent, overlap them.
answer
Most acidic to least:
0.0023M HCl
pH= 5.45 & pOH= 8.55
0.0018 M KOH
question
At a certain temperature, the pH of a neutral solution is 7.24. What is the value of Kw at that temperature?
Express your answer numerically using two significant figures.
answer
Kw =
3.3Γ10β15
question
What volume of a concentrated HCl solution, which is 36.0% HCl by mass and has a density of 1.179 g/mL, should be used to make 5.30 L of an HCl solution with a pH of 1.8?
Express your answer with the appropriate units.
answer
V = 7.22 mL
question
A certain weak acid, HA, has a Ka value of 9.7Γ10β7.
Calculate the percent dissociation of HA in a 0.10 M solution.
Express your answer as a percent using two significant figures.
answer
0.31 %
question
Calculate the percent dissociation of HA in a 0.010 M solution.
Express your answer as a percent using two significant figures.
answer
0.98%
question
Find the pH of a 0.390 M aqueous benzoic acid solution. For benzoic acid, Ka=6.5β 10β5.
Express your answer using two decimal places.
answer
pH= 2.30
question
Determine the pH of a solution that is 3.55% KOH by mass. Assume that the solution has density of 1.01 g/mL.
Express your answer using two decimal places.
answer
pH= 13.81
question
Aspirin (acetylsalicylic acid, C9H8O4) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolved 2.00 g of aspirin in 0.600 L of water and measured the pH. What was the Ka value calculated by the student if the pH of the solution was 2.60?
Express your answer numerically using two significant figures.
answer
Ka = 3.9Γ10β4
question
A 0.100 M solution of ethylamine (C2H5NH2) has a pH of 11.87. Calculate the Kb for ethylamine.
Express your answer numerically using two significant figures.
answer
Kb = 5.9Γ10β4
question
If Kb for NX3 is 3.0Γ10β6, what is the pOH of a 0.175 M aqueous solution of NX3?
Express your answer numericall
answer
pOH= 3.14
question
If Kb for NX3 is 3.0Γ10β6, what is the percent ionization of a 0.325 M aqueous solution of NX3?
Express your answer numerically to three significant figures.
answer
percent ionization =
0.304 %
question
If Kb for NX3 is 3.0Γ10β6 , what is the the pKa for the following reaction?
HNX3+(aq)+H2O(l)βNX3(aq)+H3O+(aq)
Express your answer numerically to two decimal places.
answer
pKa= 8.48
question
What is the relationship between the acid ionization constant for a weak acid (Ka) and the base ionization constant for its conjugate base (Kb )?
answer
Kaβ Kb=Kw
question
Which of the following anions act as weak bases in solution?
Check all that apply.
answer
NO2β
C2H3O2β
question
For NO2β, write an equation that shows how the anion acts as a base.
Express your answer as a chemical equation. Identify all of the phases in your answer.
answer
NO2β(aq)+H2O(l)βHNO2(aq)+OHβ(aq)
question
For C2H3O2β, write an equation that shows how the anion acts as a base.
Express your answer as a chemical equation. Identify all of the phases in your answer.
answer
C2H3O2β(aq)+H2O(l)βHC2H3O2(aq)+OHβ(aq)
question
Determine the [OHβ] of a solution that is 0.140 M in Fβ.
Express your answer using two significant figures.
answer
[OHβ] = 2.0Γ10β6 M
question
Determine the pH of this solution.
Express your answer to two decimal places.
answer
pH= 8.30
question
Determine whether each of the following cations is acidic or pH-neutral.
Sr2+
answer
pH- neutral
question
Mn3+
answer
acidic
question
C5H5NH+
answer
acidic
question
Li+
answer
pH-neutral
question
For Mn3+, write an equation that shows how the cation acts as an acid.
Express your answer as a chemical equation. Identify all of the phases in your answer.
answer
Mn(H2O)63+(aq)+H2O(l)βMn(H2O)5OH2+(aq)+H3O+(aq)
question
For C5H5NH+, write an equation that shows how the cation acts as an acid.
Express your answer as a chemical equation. Identify all of the phases in your answer.
answer
C5H5NH+(aq)+H2O(l)βC5H5N(aq)+H3O+(aq)
question
Which aqueous solution is expected to have a pH less than 7?
answer
NH4Br (aq)
question
Given that at 25.0 βC
Ka for HCN is 4.9Γ10β10 and
Kb for NH3 is 1.8Γ10β5,
calculate
Kb for CNβ and
Ka for NH4+.
Enter the Kb value for CNβ followed by the Ka value for NH4+, separated by a comma, using two significant figures.
answer
2.0Γ10β5,5.6Γ10β10
question
Keep these values in mind for the remaining questions:
Kb for CNβ is 2.0Γ10β5.
Ka for NH4+ is 5.6Γ10β10.
Identify the following salts as neutral, acidic, or basic.