Use molecular orbital theory to explain why the bond energy of an O₂ molecule is less than that of a O₂⁺ ion.

Learning Group Problem Chp 9, problem 1.

1. Given the following information, elucidate the structures of compounds A and B. Both compounds are soluble in dilute aqueous HCl, and both have the same molecular formula. The mass spectra of A and B have M+ 149. Other spectroscopic data for A and B are given below. Justify the structures you propose by assigning specific aspects of the data to the structures. Make sketches of the NMR spectra.

(a) The IR spectrum for compound A show two bands in the 3300-3500 cm-1 region. the broadband protons decoupled 13C NMR spectrum displayed for the following signals:
A: 13C NMR: 140 (C), 127 (C), 125 (CH), 118 (CH), 24 (CH2), 13 (CH3)

(b) The IR spectrum for compound A show no bands in the 3300-3500 cm-1 region. the broadband protons decoupled 13C NMR spectrum displayed for the following signals:
B: 13C NMR: 147 (C), 129 (CH), 115 (CH), 111 (CH), 44 (CH2), 13 (CH3)

1.00 mL of a 2.95 X10^-4 M solution of oleic acid is diluted wth 9.00 mL of petroleum ether, forming solution A. Then 2.00 mL of solution A is diluted with 8.00 mL of petroleum ether, forming solution B. How many grams of oleic acid are 5.00 mL of solution B? (Molar mass for oleic acid=282g/mo)

A. What was the ?H value obtained for NH3 + HCl

A sample of gas weighs 4.406g and has a volume of 1100.00 mL at 665.0 torr and 37.0 degrees C. What is the molar mass? Please show work.

Rewrite the procedure in third person & in past tense:

Procedure

You will be provided with post-mitochondrial supernatant fractions from rat liver of control rats and phenobarbitone-treated rats. Carry out the assay for drug metabolism as follows.

A

1. Take 4 ml incubation medium (containing substrate aminopyrine) into each test flask.
2. Take 4 ml incubation medium (containing no substrate into one flask (reagent blank)).
3. Add 700 ml 0.25 M sucrose solution to all flasks.
4. Pre-incubate all flasks at 37 °C for five minutes.

B

1. Add 300 ml liver homogenate supernatant to all flasks.
2. Shake unstoppered at 37 °C for 30 minutes.

C

1. Add 2 ml ZnSO₄.7H₂O (8.9%) solution to all flasks. Mix.
2. Remove flask from bath and leave for five minutes.
3. Add 2 ml saturated Ba(OH), 8H₂O solution. Mix well.
4. Transfer to 10 ml test tube and centrifuge at 200rpm for 10 minutes.

D

1. Prepare formaldehyde standards. Pipette 2.5 ml portions of each concentration into a test tube (LPS).  Use 2.5 ml water as a blank.
2. Add 1.5.ml Nash reagent to each tube and vortex.

E

1. Place 2.5 ml supernatant (from tubes treated under section C) into test tube.
2. Add 1.5 .ml Nash reagent. Vortex
3. Incubate all tubes (including standards) at 60 °C for 30 minutes.
4. Leave to cool.  Read absorbency at 412 nm against a blank reagent.
5. Read formaldehyde standards against a reagent blank.
6. Express results as ~mmol formaldehyde formed/h/g/liver (homogenate).

Chapter 7 is about Acids and Bases and Chapter 8 is about Oxidation Reduction. Write on one topic Antacids or Batteries. Choose 4 products, check the labels, list the active ingredients, and discuss in reasonable detail its use, side effects or toxicity, precaution and proper disposal

The combustion of 0.4196 g of hydrocarbon releases 17.55 kJ of heat. The masses of the products are 1.418 g of carbon dioxide (CO₂) and 0.290 g of water (H₂O). The standard formation enthalpy for CO₂(g) and H₂O(l) are −393.5 kJ/mol and −285.8 kJ/mol, respectively.

(a) What is the empirical formula of the compound?



(b) If the approximate molar mass of the compound is 76 g/mol, calculate the standard enthalpy of formation.

Δ

H

=

Ethylene oxide is produced by the catalytic oxidation of ethylene:

C2H4(g)+12 O2(g)→C2H4O(g)

An undesired competing reaction is the combustion of ethylene to CO₂.

The feed to a reactor contains 2 mol C₂H₄/mol O₂. The conversion and yield in the reactor are respectively 25% and 0.70 mol C₂H₄O produced/mol C₂H₄ consumed. A multiple-unit process separates the reactor outlet stream components: C₂H₄and O₂ are recycled to the reactor, C₂H₄O is sold, and CO₂ and H₂O are discarded. The reactor inlet and outlet streams are each at 450°C, and the fresh feed and all species leaving the separation process are at 25°C. The combined fresh feed-recycle stream is preheated to 450°C.

(a)  

Taking a basis of 2 mol of ethylene entering the reactor, draw and label a flowchart of the complete process (show the separation process as a single unit) and calculate the molar amounts and compositions of all process streams.

What is involved in a multistep synthesis? What are some challenges and opportunities?

A student designs an ammeter (a device that measures electrical current) that is based on the electrolysis of water into hydrogen and oxygen gases. When electrical current of unknown magnitude is run through the device for 2.00 min , 14.7 mL of water-saturated H2(g) is collected. The temperature and pressure of the system are 25 ∘C and 715 torr.

How many moles of hydrogen gas are produced? 5.47*10^-4 mol

Calculate the magnitude of the current in amperes if the number of moles of hydrogen gas produced is 5.47×10⁻⁴ mol (from part A).

__________

Write chemical equations for the five reactions described:

The first reaction involves the oxidation of copper with nitric acid, resulting in a blue-green colored copper (II) nitrate, Cu(NO3)2, solution.

The second reaction involves adding sodium hydroxide. This results in a double replacement or precipitation reaction produces a milky-blue copper (II) hydroxide solid.

The third reaction involves decomposition of the of the hydroxide compound to a black copper (II) oxide solid while applying heat.

After filtering the oxide, sulfuric acid is added to the solid to produce a blue copper (II) sulfate solution in a double replacement, or more specifically an acid-base reaction.

Finally, solid elemental copper is recovered through a single replacement reaction by the addition of zinc metal filings.

You find an old bottle of aspirin whose shelf life is expired. Assuming you have a bad headache, you have no other access to fresh aspirin, and you have a strong stomach can you expect to get relief from this outdated aspirin? Explain your reasoning.

Calculate [H3O + ] for a 2.5 x 10-4 M solution of weak acid (Ka = 5.3 x 10-4 )

• A.

  1.4 x 10^-4 M

• B.

  2.1 x 10^-4 M

• C.

  6.2 x 10^-4 M

• D.

  7.3 x 10^-4 M

• E.

  1.9 x 10^-4 M