A solution is 0.020 M in each Ca2+ and Cd2+. Adjusting the pH of the solution to which of the following values would achieve the best separation by precipitation of the hydroxides? solubility product constants
Best pH = ---Select--- 13.0 12.5 12.0 11.5 11.0 10.5 10.0 9.5 9.0 8.5 8.0
What would be the resulting concentrations of the ions if the solution were adjusted to this pH?
[Ca2+] = M
[Cd2+] =
M
In: Chemistry
Based on your copper solid used in RXN 1, how many grams of copper product should have been formed? Based on the copper solid in RXN 1, how many grams of the copper Hydroxide should have been formed in RXN 2? Based on the mass of copper used in RXN 1, how many grams of the zinc metal should have been used in RXN 5?
My mass of copper in RXN 1: .3595 grams
RXN1 : 4HN03 (aq) + Cu(s)-> Cu(NO3)2(aq) + 2H2O (l) + 2NO2 (g)
RXN 2: Cu(NO3)2(aq) + 2NaOH(aq) -> Cu(OH)2(s) + 2NaNO3(aq)
RXN 5: CuSO4(aq)+ ZN(s) -> Cu (s) + Zn SO4 (aq) ( Mass of zinc in RXN 5: 3.00g)
Please show all work. I am confused on how to do this.
In: Chemistry
Calculate the expected ph of the following solutions. Please show all of your work and explain your steps, if you can.
Solution 1: 50mL 0.10M NH3 + 50mL 0.10M NH4NO3
Solution 2: 10mL solution 1 + 5mL H2O + 1mL 0.10M HCl
Solution 3: 10mL solution 1 + 6mL 0.10M HCl
Solution 4: 10mL solution 1 + 5mL H2O + 1mL 0.10M NaOH
Please write legibly so I can see what steps you took!
In: Chemistry
Rank the following photons in terms of increasing energy. (Use the drop down options, and choose '1' for the lowest photon energy, '2' for the next lowest, etc.) Yellow (λ = 590 nm) Red (λ = 680 nm) Blue (λ = 443 nm) Microwave (ν = 7.5×1011 Hz) Ultraviolet (ν = 8.7×1015 Hz)
In: Chemistry
A reaction
A(aq) + B(aq) --> C(aq)
has a standard free-energy change of –3.23 kJ/mol at 25 °C. What
are the concentrations of A, B, and C at equilibrium if, at the
beginning of the reaction, their concentrations are 0.30 M, 0.40 M,
and 0 M, respectively?
In: Chemistry
A 3.0% by mass aqueous solution of hydrogen peroxide (H2O2) can be purchased at a pharmacy; by contrast, chemistry departments can purchase 30.0% by mass aqueous solution of hydrogen peroxide having a density of 1.10 g/mL at 25°C.
How many moles of hydrogen peroxide are supplied by 2.00 g of the 30.0% solution at 25°C?
How many moles of hydrogen peroxide are supplied by 2.00 mL of the 30.0% solution at 25°C.
What mass in grams of water is present in 2.00 mL of the 30.0% solution at 25°C?
How many hydrogen peroxide molecules are present per milliliter of the 30.0% solution at 25°C?
In: Chemistry
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.
In: Chemistry
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