Calculate the concentration of all species (H2SO3),(HSO3),(H3O+),(SO3-2),(OH-), pH and pOH in a 1.41M Na2SO3 (sodium sulfite) solution. The ionization constant for sulfurous acid are
H2SO3+H2O->HSO3-+H3O+ Ka1=1.4x10-2
HSO3-+H2O->SO3-2+H3O+ Ka2=6.3x10-8
In: Chemistry
Answer the following questions (a through f) based upon a peptide sequence with the following amino acids (one-letter symbols are given): EHSGLR
(a) What are the full names and three-letter abbreviations of the amino acids?
(b) At physiological pH, what is the best description of the chemical properties of the side chains(R groups)? (Hint: Select between nonpolar, polar uncharged, positively charged, negatively charged)
(c) Draw the structure of this peptide at pH 7.0.
(d) What is the net charge of the molecule at pH 3, 8, and 11? (Use pKa values for side chains and terminal amino and carboxyl groups as given in Table 3–1.)
(e) Estimate the pI for this peptide.
(f) What type of intermolecular force could the side chains form with water? (Note that these are interactions are with water, not with other amino acids.)
In: Chemistry
Why ice is less dense as a solid than as a liquid?
why is this property so important for the fish and other wildlife that live in the lakes and ponds of indiana
In: Chemistry
Which of the following statements are correct?
a) HCFCs are used as the replacement of CFCs because they do not
reach the Stratosphere.
b) HFCs are used as the replacement of CFCs (and HCFCs) because do not contain chlorine and so do not have the ozone depletion potential associated with the well-established chlorine catalytic cycles.
c) Climate projections indicate that the ozone layer will return to 1980 levels within the next 20 years.
In: Chemistry
In a chemical reaction, exactly 2 mol of substance A react to produce exactly 3 mol of substance B.
2A = 3B
How many molecules of substance B are produced when 28.2 g of substance A reacts? The molar mass of substance A is 17.9 g/mol.
Step 1. Convert the mass of A to moles.
__________________________________mol A
Step 2. Convert the number of moles of A to the number of moles of B.
___________________________________mol B
Step 3. Convert the number of moles of B to molecules of B.
___________________________________molecules of B.
In: Chemistry
1)Determine the pH of each solution.
Part A
0.20 M KCHO2
Express your answer to two decimal places.
Part B
0.21 M CH3NH3I
Express your answer to two decimal places.
Part C
0.22 M KI
Express your answer to two decimal places.
2)
Part A
Rank the following compounds in order of decreasing acid strength using periodic trends.
Rank the acids from strongest to weakest. To rank items as equivalent, overlap them.
LiH, H2O, HCl, HBr
In: Chemistry
Information regarding the question:
Concentration of NaOH=0.05138 M
Concentration of Crystal Violet Dye Solution=0.001 M
Room Temperature=25 degree Celcius
Absorbance from the device- spectrovis(spectrophotometer)
Time: Trial 1 Trial 2
0 0.089 0.430
30 0.106 0.323
60 0.121 0.248
90 0.106 0.187
120 0.063 0.141
150 0.045 0.109
180 0.028 0.082
210 0.023 0.060
240 0.014 0.045
270 0.010 0.036
300 0.005 0.027
330 0.003 0.017
360 0.000 0.015
390 -0.001 0.008
420 -0.002 0.006
450 -0.002 0.007
The following calculations must be handwritten in your notebook. – Conversion of %Transmittance to Absorbance ■ Only one handwritten sample is necessary ■ However, all of your %Transmittance values must be converted to Absorbance in your Data Table
–The steps you took to determine the order with respect to the Crystal Violet Dye (X in the example)
– The steps you took to determine the order with respect to the NaOH (Y in the example)
– The steps you took to determine k – The overall, Modified Rate Law ■ With your values for X, Y, and k inserted into the equation
– Solve the Rate Law ■ Insert in all values necessary Result
In: Chemistry
ammonia is a common constituent of many natural waters and wastewaters. when water containing ammonia is treated at a water treatment plant, the ammonia reacts with the disinfectant hypochlorous acid (HOCl) in solution to form monochloroamine (NH2Cl) as follows:
NH3 + HOCl > NH2Cl + H2O
The rate law for this reaction is:
d[NH3]/dt = -k[HOCl][NH3]
a) what is the reaction order with respect to NH3?
b) What order is this reaction overall?
c) If the HOCl concentration is held constant and equals10^-4 M, and the rate constant equals 5.1 x 10^6 L/moles-s, calculate the time required to reduce the concentration of NH3 to one half its original value.
In: Chemistry
Which reaction type is each chemical reaction, Precipitation, Acid-base, or Oxidation-reduction(redox)
1. CuSO4(aq)+Ba(ClO4)2(aq)-->BaSO4(s)+Cu(ClO4)2(aq)
2. 4Mn2++5BiO-3(aq)+2OH-(aq)-->H2O(I)+4MnO-4(aq)+5Bi+(aq)
3.NH4OH(aq)+HCl(aq)-->H2O(l)+NH4Cl(aq)
4. H2C2O4+2NaOH(aq)-->H2O(l)+Na2C2O4(aq)
5. MgCl2(aq)+Pb(NO3)2(aq)-->PbCl2(s)+Mg(NO3)2
6. 4Zn(s)+NO-3(aq)+7H2O(l)-->4Zn2+(aq)+NH+4(aq)+10OH-(aq)
7. Hg2(OOCCH3)2(aq)+SrI2(aq)-->Hg2I2(s)+Sr(OOCCH3)2(aq)
8.2HCl(aq)+K2S(aq)-->H2S(g)2KCl(aq)
9. 2H3PO4(aq)+3Ca(OH)2(aq)-->3H2O(l)+Ca3(PO4)2(aq)
10. 4Fe(s)+3O2(g)-->2Fe2O3(s)
In: Chemistry
|
CO (g) |
CO2 (g) |
H2O (g) |
H2O (l) |
|
‐137.1 |
‐394.01 |
‐228.4 |
‐274.4 |
Given the above standard free energies of formation at 25oC in kJ/mole,
(a) Find ΔGo and the equilibrium constant Kp for the reaction CO (g) + H2O (g)CO2 (g) + H2 (g) at 25oC
(b) Find the vapor pressure of H2O (g) at 25oC.
(c) If CO (g) , CO2 (g) and H2 (g) are mixed so that the partial pressure of each is 1.00 atm and the mixture is brought into contact with excess liquid H2O, what will be the partial pressure of each gas when equilibrium is attained at 25oC? The volume available to the gases is constant.
In: Chemistry
Kp = 6.5 × 104 at 308 K for the
following reaction:
2 NO (g) + Cl2(g) ⇌ 2
NOCl(g)
At equilibrium, PNO = 0.35 atm and
PCl2 = 0.10 atm
What is the equilibrium partial pressure of NOCl(g)?
In: Chemistry
Given the following equilibrium system:
2SO2(g) + O2(g) ↔ 2SO3(g) +
99.1 kJ
If additional SO2(g) is added to the system while the
temperature and pressure are kept constant. Compared to its
original concentration, how will the concentration, of oxygen
change?
Increase
Decrease
Remain the Same
The pressure on the system is increased while the temperature is
kept constant. Compared to its original concentration, how will the
concentration of SO2(g) change?
Decrease
Increase
Remain the Same
A catalyst is added to the above equilibrium system while the
temperature and pressure are kept constant. Compared to its
original concentration, how will the new equilibrium concentration
of SO2(g) change?
Remain the Same
Increase
Decrease
The temperature of the equilibrium system is decreased and the
pressure is kept constant. Compared to its orginal concentration,
how will the new equilibrium concentration of SO2(g)
change?
Remain the Same
Increase
Decrease
In: Chemistry
If the solution was not continuously stirred while performing the freezing point determination, what effect might that have on the experimental results? Briefly explain.
In: Chemistry
1. In the Deacon process for the manufacture of chlorine, HCl
and O2 react to form Cl2 and
H2O. Sufficient air (21 mole% O2, 79% N2) is fed to provide 35%
excess oxygen, and the
fractional conversion of HCl is 85%.
(a) Calculate the mole fractions of the product stream components,
using atomic species
balances in your calculations.
(b) Again calculate the mole fractions of the product stream
components, only this time
use the extent of reaction in the calculations.
(c) An alternative to using air as the oxygen source would be to
feed pure oxygen to
the reactor. Running with oxygen imposes a signi cant extra process
cost relative to
running with air, but also offers the potential for considerable
savings. Speculate on
what the cost and savings might be. What would determine which way
the process
should be run?
In: Chemistry
4. Cr has four isotopes:
Cr 50
Cr 52
Cr 53
Cr 54
A) Determine how many protons, neutrons and electrons each isotope has.
B) The atomic mass reported for Cr is 54.94. What does this tell us about the relative abundance of each isotope? What isotope should be the most abundant?
C) Write the electronic configuration of the Cr, taking into account that studies show that it has a paramagnetism equivalent to 6 unpaired electrons. Determine the quantum numbers for the last electron 4s of Cr.
D) Determine the effective nuclear charges for the following Cr electrons:
---An electron 4s
---A 3d electron
Please try to write everything in an organized maner and legible handwritting.
In: Chemistry