Electric generating plants transport large amounts of hot water
through metal pipes, and oxygen dissolved in the water can cause a
major corrosion problem. Hydrazine (N2H4)
added to the water avoids the problem by reacting with the oxygen:
N2H4(aq) + O2(g)
→ N2(g) + 2 H2O(l)
About 4 x107 kg of hydrazine is produced every year by
reacting ammonia with sodium hypochlorite in the Raschig
process:
2 NH3(aq) + NaOCl(aq) →
N2H4(aq) + NaCl(aq) +
H2O(l) ΔrH° = −151 kJ
(a) If ΔfH° of NaOCl(aq) =
−346 kJ/mol, find ΔfH° of
N2H4(aq) given that
ΔfH° [NH3(aq)] = −80.83
kJ/mol, ΔfH° [NaOCl(aq)] = −346
kJ/mol, ΔfH° [Na+(aq)] =
−239.66 kJ/mol, ΔfH°
[Cl−(aq)] = −167.46 kJ/mol and
ΔfH° [H2O(l)] = −285.840
kJ/mol.
______ kJ/mol
b) What is the heat released when aqueous
N2H4 is added to 6.00 × 103 L of
plant water that is 2.50 × 10−4 mol/L O2?
Enter your answer in scientific notation.
____× 10___ kJ
In: Chemistry
1.True or false
A. All compounds that contain hydrogen are acids..
B. A solution with a pH of 5 has 10 times higher [H+] than a
Solution with a pH of 6.
C. SO3 in the atmosphere is one cause of acid rain.
D. Agricultural chemicals are the only cause of water pollution.
E. One function of an auto catalytic converter is to convert CO2 to CO
F. The major elements in air are nitrogen and oxygen
G As a radioactive isotope decays its half life changes.
H. In the same size container at the same temperature, 25g of N2 gas
has the same pressure as 25g of NH3 gas..
I Chloroflurocarbon compounds are considered to be a prime cause of
ozone depletion in the stratosphere.
J. Beta radiation from an atom is the emission of a valence electron.
In: Chemistry
Fe(NO3)3+KSCN ---- FeSCN^2+KNO3
the assumption was made that all of the SCN^- which had been added to the standard solutions had been converted to FeSCN^2+.
Is this assumption reasonable. Explain considering the initial concentration of SCN- relative to that of Fe3+ in each sample
| soln |
0.200M Fe(NO3)3 (ml) |
0.00200M KSCN (ml) |
water (ml) |
FeSCN2+ (ml) |
|---|---|---|---|---|
| 1 | 5.00 | 0.20 | 4.80 | 4x10^-5 |
| 2 | 5.00 | 0.40 | 4.60 | 8x10^-5 |
| 3 | 5.00 | 0.60 | 4.40 | 1.2x10^-4 |
| 4 | 5.00 | 0.80 | 4.20 | 1.6x10^-4 |
| 5 | 5.00 | 1.00 | 4.00 | 2.00x10-4 |
In: Chemistry
1. 3. Consider the dissociation of acetic acid: CH3COOH(aq) + H2O(l) ⎯→ ←⎯ CH3COO-(aq) + H3O+(aq) Ka = 1.8 x 10-5 pKa = 4.74
a. Write the equilibrium expression.
b. Would the addition of an aqueous solution of sodium hydroxide favor the dissociation of acetic acid? Explain your answer.
c. Would the addition of an aqueous solution of sodium acetate favor the dissociation of acetic acid? Explain your answer.
In: Chemistry
Not counting solubility relations and effectiveness for removal of impurities, in whatrespects would hexyl alcohol be a less desirable crystallization solvent thanmethanol or ethanol (hint: look at MSDS physical and chemical properties)
In: Chemistry
Write the net ionic equation for the following reactions in solution.
A) Solutions of lithium chromate and barium chloride are mixed
B) Solutions of ammonium acetate and barium hydroxide are mixed
C) Solutions of Acetic acid and potassium hydrogen carbonate are mixed
In: Chemistry
Substance Q reacts according to a first order rate law with k = 5.0 x 10-5 s -1 .
a. If the initial concentration of the reaction is 1.00 M for Q, what is the initial rate of the reaction?
b. What is the rate after 1.00 hr?
In: Chemistry
What volume of 6.00 M HNO3 is needed to make 500.0 mL of a 0.250 M solution?
In: Chemistry
What are glycosaminoglycans, and why are sugars good candidates for molecules that fill that role
In: Chemistry
In: Chemistry
|
When a solid dissolves in water, heat may be evolved or
absorbed. The heat of dissolution
(dissolving) can be determined using a coffee cup
calorimeter. When I type the answer, will it have to be negative? |
In: Chemistry
To prepare a solution of NaCl, you weight out 2.634 (±0.002) g and dissolve it in a volumetric flask whose volume is 100.00 (±0.08)mL. Express the molarity of the solution, along with its uncertainty, with an appropriate number of digits. [Molecular mass of NaCl, 58.443 (±0.001) g/mol].
In: Chemistry
Calculate the pH change when 10. mL of 3.0 M NaOH is added to 500. mL of the following:
(a) pure water
(b) 0.10 M CH3COO-
(c)0.10 M CH3COOH
(d)a solution that is 0.10 M CH3COO- and 0.10 M CH3COOH
In: Chemistry
a) Calculate the potential in the following cell (no current is flowing)
Zn|Zn2+(1.00M)|| UO2 2+(1.00M), U4+ (0.1M), H3O + (1.00M) |Pt
b) The cathode has a volume of 50 mL. What is the cell potential (no current) after adding 10 mL, 25 mL, 50 mL, and 100 mL 1M NaOH to the cathode?
c) What is the Gibbs Free Energy for the 5 cells in a) and b). What is the spontaneous reaction in each case?
In: Chemistry
This is for the verification of beer-lambert law experiment.
|
Volume of copper sulphate solution /mL |
Volume of Concentrate d ammonia /mL |
Final volume of solution /mL |
[CuSO4]/m ol dm-3 |
[CuSO4]/pp m |
[CuSO4]/mg dm-3 |
Transmit tance /% |
Absorbance |
|
0 |
25 |
25 |
101.5 |
0.006 |
|||
|
1 |
24 |
25 |
95.9 |
0.018 |
|||
|
2 |
23 |
25 |
89.9 |
0.046 |
|||
|
3 |
22 |
24 |
86.7 |
0.062 |
|||
|
4 |
21 |
25 |
81.4 |
0.090 |
Can someone show one sample example of how to determine the three ways the following concentrations can be calculated.
Original Concentration of CuSO4.5H2) = 0.1015 mol/dm3 . 25mL of this was then taken and dissolved in water up to 250mL flask.
Concentration of the ammonia= 17.64mol/L. Ammonia was not diluted.( at 600nm)
OD values for calibration? I am not too sure what that means.
In: Chemistry