Polyglycine, a simple polypeptide, can form a helix with ϕ=−80∘ ,
ψ=+150∘ . From the Ramachandran plot (see the figure on the left),
describe this helix with respect to handedness.
Check all that apply.
It could be left-handed helix.
It could have 310 helix structure.
It could have parallel β strands structure.
It could have α helix structure.
It could have antiparallel β strands structure.
It could have polypeptide II helix structure.
It could be right-handed helix.
In: Chemistry
please show work
An industrial chemist introduces 2.0 atm of H2 and
2.0 atm of CO2 into a 1.00−L container at 25.0°C and
then raises the temperature to 700°C, at which
Kc = 0.534:
H2(g) + CO2(g) ⇌
H2O (g) + CO(g)
How many grams of H2 are present at equilibrium?
In: Chemistry
#9 Writing and Interpreting a Rate Law Expression
1. The gas phase reaction of nitric oxide and oxygen yields nitrogen dioxide:
2 NO (g) + O2 (g) ----> 2 NO2 (g)
The rate law is rate = k[NO]2[O2].
a. What is the reaction order with respect to each reactant and what is the overall reaction order?
b. What are the units for k if time was expressed in units of minutes?
c. If the concentration of NO was doubled and the concentration of O2 was halved, what would happen to the rate?
d. If the NO was unchanged and the concentration of O2 was doubled, what would happen to the rate?
e. If both of the reactants were tripled, what would happen to the rate?
2. The reaction…
2 ICl (g) + H2 (g) ------> I2 (g) + 2 HCl (g)
is first order in H2 and first order in ICl. Write the rate law expression and specify the units of the rate constant, k.
3. The reaction of CO and NO2 is second order with respect to NO2 and zero order with respect to CO.
a. Write the rate law expression.
b. Expressing time in units of seconds, what are the units for k?
c. How does the reaction rate change if the CO concentration is decreased by a factor of 5?
d. What is the change in the rate if the concentrations of both reactants is doubled?
4. Using time units of hours, what would the units for k be for a reaction that is 1½ order?
5. For the following rate law…
Rate = k[NO2]2[H2]
a. What is the order with respect to each reactant?
b. What is the overall order for the reaction?
c. What are the units for the rate constant, k, if the time unit is seconds?
d. What would happen to the rate if each reactant was quadrupled?
e. What would happen to the rate if NO2 was unchanged and the H2 was halved?
In: Chemistry
8. Draw a flow diagram for this experiment. Indicate which phase contains each of the compounds in the mixture.
10. Why is it essential to carefully separate the layers during an extraction? What would happen if the layers were not separated completely?
11. You are given an impure solid that contains 70% of the desired product. After extracting 15 g of the material, you recover 6 g of the pure compound. What is the correct recovery?
12. how extraction works
13. The chemical process tha occurs during the extraction process
14. What was the reagent that you extracted in each phase
In: Chemistry
7.0 E 2 of a 50:50 mixture on n-propanol (CH3CH2CH2OH) and n-butanol (CH3CH2CH2CH2OH) are discharged into a body of water containing 1.0 E 10 L of H2O. What is the BOD of this water?
In: Chemistry
Arrange the following ions in order of increasing ionic radius:
1.) potassium ion, calcium ion, sulfide ion, chloride ion
2.)barium ion, iodide ion, telluride ion, cesium ion
In: Chemistry
Balance the following oxidation–reduction equation. The reactions occur in a basic aqueous solution.
Cd2++ H 2S → Cd + S 8
S2- + F2 → SO42- + F-
Cr + NO3- → Cr(OH)4- + NH3
MnO4- + C2O42- → MnO2 + CO2
In: Chemistry
a)What is the pH of a solution prepared by adding 25.00 ml of 0.0993 M sodium hydroxide to 30.00 mL of 0.0553 M acetic acid? There will be a reaction. What two major species remain and how much of each?
b) What is the pH of 9.93x10^-8 M potassium hydroxide?
c) What is the volume of 0.579 M sodium hydroxide required to reach the equivalence point of a titration of 10.0 mL of 5.00% (by mass) acetic acid?
d) What is the pH at the equivalence point in the titration above?
*Please show steps to understand completely*
In: Chemistry
Solve an equilibrium problem (using an ICE table) to calculate
the pH of each of the following solutions.
A. a mixture that is 0.15M in HF and 0.15M in NaF
B.0.15M NaF
C. 0.15M HF
In: Chemistry
Formic acid (HCO2H) is an organic acid secreted by ants and stinging nettles.
Calculate the pH in 0.21M HCO2H (Ka=1.8
In: Chemistry
at 25 C, a solution is prepared by adding 50 ml of 0.2 M NaOH to 75 ml of 0.1 M NaOH. What is the total concentratoin of hydorxide ion in the solution? Assume volumes are additive.
In: Chemistry
a hydrogen atom in the ground state absorbs a photon of light with a wavelength of 97.3nm causing the electron to jump to an unknown energy level. the electron then relaxes emitting a photon of light in the visible range, what is the wavelength of the emitted photon?
In: Chemistry
Write the dissociation reaction for the following acids in water H2O. State whether the acid is a strong acid or a weak acid. Is the reaction reversible? Identify the acid, base, conjugate acid, and conjugate base.
State the Dissociation reaction, Strong or Weak Acid, Is it reversable, Acid, Base, Conjugate Acid, Conjugate Base for each. PLEASE SHOW WORK, AND EXPLAIN.
1. H2CO3
2.HCI
3. HNO3
4. Write the equation that represents the reaction of hydrochloric acid in water.
Conjugate acid-base pair that includes hydrochloric acid:
Conjugate acid-base pair that does not include hydrochloric acid:
Does water act as an acid or a base in this reaction?
In: Chemistry
2H2S(g)<---> 2H2(g) + S2(g)
The value of Kc for the thermal decomposition of hydrogen sulfide is 2.2x10^-4 at 1400 K. A sample of gas which [H2S]=4.60 M is heated to 1400 K in a sealed vessel. After chemical equilibrium has been achieved, what is the value of [H2S] in M? Assume no H2 or S2 was present in the original sample.
In: Chemistry
A pediatrician orders Cephalexin 12.5 mg/ kg by mouth (po) every 12 hours (bid). The child weighs 33 pounds (lbs). The pharmacist provides you with Cephalexin oral suspension 100 mg/mL. How many milliliters (mL) of Cephalexin will you administer bid? (1 kg = 2.2 lbs) HLEP! I NEED ANSWER ASAP!
In: Chemistry