A 7.95-atm PCl5 is initially placed in an empty vessel at 25˚C. Calculate Kp if the equilibrium partial pressure of Cl2 is 3.00 atm at the same temperature.
I am completely lost on how to even start the problem, let alone solve it.
In: Chemistry
This is for the lab practical I take on Tuesday night. If you could answer each one and show your work/ explain that'd be amazing so I can do well on the actual practical on Tuesday! Thank you!
Chemistry 211 Lab Final Study Guide Spring 2015
Useful Information:
1 ampere =coulomb/sec
Faraday’s constant = 96,500 coulombs/mole of electrons
Molar mass of Au = 197.0 g/mole, Molar mass of Cu = 63.55
g/mole
m = moles , ' ’
c kg
ΔTf
= Tf
− Tf
where Tf is for the pure solvent and Tf
is for the mixture.
ΔT = (K
)(m ) ,
m = (
(mass of
solute, g )
)( ).
f f c
c molar
mass, g
mol −1
mass of
solvent, kg
7. Next question
(a) If you weigh 6.355 grams of copper, add concentrated nitric acid to dissolve it, and then dilute the solution to a total volume of 50 mL, how many moles of copper are in this solution?
(b) For the equilibrium reaction 3H2(g) + N2(g) →
2NH3(g), what is the equilibrium constant expression, Kc, for this
reaction? (5pts)
8. Suppose at some temperature, the equilibrium
concentration of H2 is 0.45M, the equilibrium concentration of N2
is 0.38M, and the equilibrium concentration of NH3 is 0.42M. What
is the value of the equilibrium constant for the reaction 3H2(g) +
N2(g) → 2NH3(g) at this temperature? (Show your work. No credit
will be given if your work is not shown.)
9. Next question
(a) If you need 0.0534 moles of NaOH to reach
equivalent point in the titration with acetic acid, how many mL of
0.09876M NaOH will you need?
(b) The Ksp of Cu(OH)2 is 2.2x10-20, what is the
solubility of Cu(OH)2?
10. Next question
(a) In non-sulfide qualitative analysis of
representative cations, the Group A cations comprising of Pb2+,
Hg2+, and Ag+ give a precipitate with
solution.
(b) From a solution containing mixture of Pb2+, Fe3+,
and Al3+, Pb2+ is removed by adding HCl solution. To the remaining
cation mixture, on making the solution basic with NH3 (pH=9 – 10),
both the cations form precipitate. Further analysis of the cation
mixture containing Fe3+ and Al3+ is carried out by adding NaOH
solution.
Aluminum hydroxide (dissolves/remains undissolved) in
NaOH solution while Ferric hydroxide
( dissolves/remains undissolved).
(c) Fe(OH)3 precipitate is dissolved in minimal amount
of aqueous HCl which gives a
yellow solution. To this solution addition of solution
(at pH = 4 – 5) yields a dark blue solid known as Prussian
Blue.
(d) Describe the method for checking for completeness of precipitate in qualitative analysis of ions.
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Which of the following statements is false?
| Electron affinity is a measure of the energy evolved when a gaseous atom gains an electron |
| Anions are smaller than the parent atoms from which they are derived |
| Ionization energies decrease as the atomic radius increases |
| For isoelectronic cations, the higher the charge, the smaller the ion |
| Cations are smaller than the parent atoms from which they are derived |
In: Chemistry
The acid ionization constant for Ga(H2O)63+ (aq) is 2.5×10-3 . Calculate the pH of a 0.1500 M solution of Ga(NO3)3 .
In: Chemistry
Acid HX is a weak acid with Ka=1.0x10-6. A 50.0 mL sample of 1.00 M HX(aq) is titrated with 1.00 M NaOH(aq). What is the pH of the solution at the points listed below during titration?
A. pH 1.00M HX solution before titration:
B. pH after 25.0mL 1.00M NaOH added:
Please show work! Thank you!
In: Chemistry
Please Give All 3 answer.
Q1) A student was given a sample of crude salicylic acid to recrystallize. The initial mass of the crude acid was 131 mg. The mass after recrystallization was 121 mg. Calculate the percent recovery from recrystallization.
Q2) If 91.0 g of oxalic acid and 79.0 g of methanol react to form 89.0 g of dimethyl oxalate and water, what is the percent yield?
Q3) A student measures out exactly 0.109 g of salicylic acid and runs the experiment as dictated in the lab manual. They obtain 0.101 g of aspirin. What is the percent yield for their reaction?
In: Chemistry
pMice that are completely lacking the Adenine nucleotide translocase gene (Ant-/-) are viable (which is surprising) and show the following physiological phenotypes:
nHighlevels of alanine, lactate and succinate (in serum).
nAsix-fold increase of mitochondrial hydrogen peroxide as compared with normal control mice.
pGive reasonable biochemicalexplanations to each of these observations.
In: Chemistry
Calculate the concentrations of all species in a 0.540 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4× 10–2 and Ka2 = 6.3× 10–8.
In: Chemistry
Chlorine can be prepared in the laboratory by the reaction of manganese dioxide with hydrochloric acid, HCl(aq), as described by the chemical equation: MnO2(s) + 4HCl --> MnCl2 (aq) + 2H2O (l) + Cl2 (g) How much MnO2(s) should be added to excess HCl(aq) to obtain 405 mL of Cl2(g) at 25 �C and 805 Torr?
In: Chemistry
Calculate the pH during titration of 25 mL of 0.175 M HCN with 0.3 M NaOH after the addition of 0 mL, 7.29mL, 14.5833 mL, and 20 mL base. Show all work.
In: Chemistry
QUESTION 1
Calculate the mass of SO3 formed when 9.42 g of SO2 reacts with 4.50 g of O2 according to the following reaction.
2SO2 + O2 → 2SO3
| a. |
22.52 g |
|
| b. |
11.77 g |
|
| c. |
11.25 g |
|
| d. |
34.27 g |
|
| e. |
5.63 g |
QUESTION 2
If 12.002g of potassium oxalate hydrate is added to a beaker and then 20mL of DI water is added to dissolve and then 8.0mL of 1.5 M FeCl3 is added. Which statement is correct
| a. |
the beaker contains 0.173 moles of potassium oxalate hydrate and 0.012 moles of iron(III) chloride |
|
| b. |
the beaker contains 0.0651 moles of potassium oxalate hydrate and 0.012 moles of iron(III) chloride |
|
| c. |
the beaker contains 3.255 moles of potassium oxalate hydrate and 0.012 moles of iron(III) chloride |
|
| d. |
the beaker contains 0.012 moles of potassium oxalate hydrate and 0.0651 moles of iron(III) chloride |
|
| e. |
the beaker contains 3.255 moles of potassium oxalate hydrate and 12.0 moles of iron(III) chloride |
QUESTION 3
The reaction of 35.0 g of Al with excess g of Cr2O3 produced 25.6 g of Cr. What is the percent yield for this reaction?
2Al + Cr2O3 → Al2O3 + 2Cr
| a. |
51.0% |
|
| b. |
196.3% |
|
| c. |
73.1% |
|
| d. |
75.9% |
|
| e. |
37.9% |
QUESTION 4
Chlorine gas can be made from the reaction of manganese dioxide with hydrochloric acid.
MnO2(s) + 4HCl(aq) → MnCl2(aq) + 2H2O(l) + Cl2(g)
According to the above reaction.
If 1.5 moles of MnO2 are reacted with 5.6 moles of HCl which of the following statements is true?
| a. |
HCl is the limiting reactant and 11.2 mol of water is produced |
|
| b. |
HCl is the limiting reactant and 2.8 mol of water is produced |
|
| c. |
MnO2 is the limiting reactant and 3.0 mol of water is produced |
|
| d. |
HCl is the limiting reactant and 5.8 mol of water is produced |
|
| e. |
MnO2 is the limiting reactant and 5.8 mol of water is produced |
In: Chemistry
For the reactions shown below, we added 2.25 mL of 0.0450 M HCl to a test tube containing one of the two cations (Ag+ or Pb2+) and recovered 0.0141 g of precipitate.
AgNO3(aq) + HCl(aq) →
AgCl(s) + HNO3(aq)
Pb(NO3)2(aq) + 2 HCl(aq) →
PbCl2(s) + 2 HNO3(aq)
How much precipitate in moles would be recovered theoretically
if the ion was Ag+? (Enter an unrounded value. Use at
least one more digit than given.)
mol
How much precipitate in moles would be recovered theoretically if
the ion was Pb2+? (Enter an unrounded value. Use at
least one more digit than given.)
mol
How much precipitate in grams would be recovered theoretically if
the ion was Ag+?
g
How much precipitate in grams would be recovered theoretically if
the ion was Pb2+?
g
Based on the precipitate amount recovered, which of the two ions
was in the unknown?
Ag+
Pb2+
In: Chemistry
Calculate the equilibrium concentration of undissociated in a glycolic acid solution with an analytical glycolic acid concentration of 0.0824 and a pH of 3.180.
In: Chemistry
Do you predict that maltose will reduce cupric ion in Fehling
In: Chemistry
For the reactions shown below, we added 3.75 mL of 0.0450 M Na2S to a test tube containing one of the two cations (Cu2+ or Cd2+) and recovered 0.0161 g of precipitate.
Cu(NO3)2(aq) +
Na2S(aq) → CuS(s) + 2
NaNO3(aq)
Cd(NO3)2(aq) +
Na2S(aq) → CdS(s) + 2
NaNO3(aq)
How much precipitate in moles would be recovered theoretically
if the ion was Cu2+? (Enter an unrounded value. Use at
least one more digit than given.)
mol
How much precipitate in moles would be recovered theoretically if
the ion was Cd2+? (Enter an unrounded value. Use at
least one more digit than given.)
mol
How much precipitate in grams would be recovered theoretically if
the ion was Cu2+?
g
How much precipitate in grams would be recovered theoretically if
the ion was Cd2+?
g
Based on the precipitate amount recovered, which of the two ions
was in the unknown?
Cu2+
Cd2+
In: Chemistry