In each of the following balanced oxidation-reduction equations, identify those elements that undergo changes in oxidation number and indicate the magnitude of the change in each case.

2MnO4−(aq)+3S2−(aq)+4H2O(l)→3S(s)+2MnO2(s)+8OH−(aq)   

4H2O2(aq)+Cl2O7(g)+2OH−(aq)→2ClO2−(aq)+5H2O(l)+4O2(g)

Ba2+(aq)+2OH−(aq)+H2O2(aq)+2ClO2(aq)→Ba(ClO2)2(s)+2H2O(l)+O2(g)

In chemical reactions, heat is converted into chemical energy (the potential energy stored in chemical bonds) or vice versa. Bond energy is the energy required to break one mole of the bond in the gas phase. Since it takes energy to break a bond, bond energies are always positive. Conversely, energy is released when bonds are formed. Thus, the enthalpy change for a reaction can be approximated from ΔHrxn=∑(ΔHbreaking)+∑(ΔHforming) where H represents bond energies for the breaking (positive bond energy) or forming (negative bond energy) of a bond and Hrxn represents the overall enthalpy for the reaction. Use the table to answer questions about bond energies. Bond Bond energy (kJ/mol )

C−C 347

C=C 611

C−H 414

C−O 360

C=OinCO2 799

O−O 142

O=O 498

H−O 464

Calculate the bond energy per mole for breaking all the bonds in methane, CH4. Express your answer to four significant figures and include the appropriate units.

Calculate the bond energy per mole for breaking all the bonds of oxygen, O2? Express your answer to three significant figures and include the appropriate units.

Calculate the bond energy per mole for forming all the bonds of water molecules, H2O. Express your answer to three significant figures and include the appropriate units.

Calculate the bond energy per mole for forming all the bonds of carbon dioxide, CO2. Express your answer to four significant figures and include the appropriate units. ΔHCO2 =

Describe the stage of polymerization through which a phenolic resin passes to become thermoset.

give the structure corresponding to the name (s)-4-chloro-2-pentyne

derive butler-volmer equation from Arrhenius equation

please show all steps

Calculate ΔHrxn for the following reaction:

CaO(s)+CO2(g)→CaCO3(s)

Use the following reactions and given ΔH values: Ca(s)+CO2(g)+12O2(g)→CaCO3(s), ΔH= -812.8 kJ

2Ca(s)+O2(g)→2CaO(s), ΔH= -1269.8 kJ

Express your answer using four significant figures.

what is the degree of polymerization (DP) of LDPE having an average molecular weight (mass) of 27,980?

Zinc metal reacts with hydrochloric acid according to the following balanced equation. Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g) When 0.107 g of Zn(s) is combined with enough HCl to make 54.9 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.0 ∘C to 24.0 ∘C.

Find ΔHrxn for this reaction as written. (Use 1.0 g/mL for the density of the solution and 4.18 J/g⋅∘C as the specific heat capacity.)

Calculate the pH of the following solutions.

A.) 0.36 M NH4NO3

B)0.50 M Ca(NO3)2

C.)0.080 M C6H5NH2

D.) 0.45 M KNO2

5. Suggest 5 ways that the concentration of PH₃ could be increased in the following reaction.

P_{4 (g)} + 6 H_{2 (g)} ⇌ 4 PH_{3 (g)}        ΔH^o = 110 kJ/mol

6. Gaseous nitrogen dioxide forms gaseous dinitrogen tetroxide with a k_eq = 164 at 25°C in a 2.00L container

            a. Write and balance the equation

b. If at a given timepoint the concentrations of nitrogen dioxide was measured to be 0.500 M and the concentration of dinitrogen tetroxide was measured to be 1.25 M, is the reaction at equilibrium?

            c. What are the concentrations at equilibrium?

d. After the initial equilibrium, if 5.00mol of dinitrogen tetroxide was introduced into the container, what are the concentrations of both species when equilibrium reestablishes?

Which of the following reactions is/are redox reactions?  You may select more than one reaction.

In the body, mercury's toxic effects are known to result from its ability to disrupt and insert into S-S bonds in critical enzymes. Fish, particularly tuna, which contain high levels of methylmercury are frequently found to also have high levels of selenium. Given the low rate of mercury poisoning even in populations where large quantities of fish are consumed, this has led some to speculate that selenium serves to protect against mercury poisoning. Explain the chemical basis for this theory

An industrial wastewater contains a total cyanide concentration of 10-3M and a total nickel concentration of 210-4M. Calculate the concentrationof all species (HCN, CN-, Ni2+, and all cyanide and hydroxy complexes of nickel) at pH 9.0. State and verify all assumptions.

A pH 3.30 buffer is prepared from iodoacetic acid ICH₂COOH (pK_a = 3.175), and sodium iodoacetate, ICH₂COO^-Na⁺ . If ionic strength of the buffer solution must not exceed 0.200 M, what are the maximum concentrations of the two components that could be used?

What volume of KOH (conc = 1.850 M), could be added to 50.00 mL of the buffer solution of part (a), before the pH would increase to 4.000?

1. Compare the advantages and disadvantages of each pH method (i.e. cost, ease of use- time it takes to set up and take a pH measurement) including accuracy and precision of each method.

2. draw a diagram labeling the two silver/ silver chloride reference electrodes, glass membrane, and porous frit.

3. show how a charge is built up and produces a voltage that is measured.