Calculate Delta H rxn for the following reaction (watch the significant figures)

2 NOCl (g) --> N2(g) + 02(g) + Cl2(g)

Given the following set of reactions;

1/2 N2(g) + 1/2 02(g) ---> NO(g) Delta H= 90.3KJ
NO(g) + 1/2 Cl2(g) ---> NOCl(g) Delta H = - 38.6 KJ

Chromic acid (H₂CrO₄) is an acid that is used in ceramic glazes and colored glass. The pH of a 0.070 M solution of chromic acid is the same as the pH of a 0.054 M HNO₃ solution. Calculate K_a for chromic acid.

A hydrogen-oxygen fuel cell is used in the space program to generate clean energy. Describe, in detail, the principle and process of electrical energy generation from hydrogen-oxygen fuel cell. Also include in the discussion major advantages and limitations of such fuel cells.

The solutions at the two Pb electrodes of a concentration cell were prepared as follows:

Cell A: A mixture of 1.00 mL of 0.0500 M Pb(NO3)2 with 4.00 mL of 0.0500 M KX (the soluble potassium salt of an unspecified monovalent ion X-). Some PbX2(s) precipitates.

Cell B: 5.00 mL of 0.0500 M Pb(NO3)2.

The cell potential was measured to be 0.05100 V at 25 °C.

1.)By use of the Nernst equation, determine the concentration (M) of Pb2+ in the solution of Cell A.

2.)In Cell A, how many moles of X- have reacted with Pb2+?

3.)What is the concentration (M) of X- in the solution of cell A.

4.) Calculate Ksp of PbX2.

(a) Calculate the standard free-energy change (ΔG°) for the following oxidation-reduction reaction. Cu(s) + Br2(aq) → Cu2+(aq) + 2 Br−(aq)

(b) Calculate the equilibrium constant for this reaction at 298 K.

Describe the preparation of 40 L 0.02 M phosphate buffer, pH 6.9 starting from Solid KH₂PO₄ and K₂HPO₄

What is the minimum mass of ice at 0.0 C that must be added to 1 kg of water to cool the water from 28 C to 12 C? (heat of fusion = 333 J/g, Specific heat capacity of ice = 2.06 J/g K, water = 4.184J/g K)

Determine whether the entropy increases or decreases in the given situations.

a. A vapor that turned to solid
b. A vapor condenses to a liquid
c. A mole of vapor becomes solid
d. A liquid freezes
e. A solute dissolved in a solvent

A rigid stainless steel chamber contains 210 Torr of methane, CH4, and excess oxygen, O2, at 200.0

A 100.0 mL solution containing 0.976 g of maleic acid (MW = 116.072 g/mol) is titrated with 0.296 M KOH. Calculate the pH of the solution after the addition of 56.00 mL of the KOH solution. Maleic acid has pKa values of 1.92 and 6.27

. pH =

At this pH, calculate the concentration of each form of maleic acid in the solution at equilibrium. The three forms of maleic acid are abbreviated H2M, HM–, and M2–, which represent the fully protonated, intermediate, and fully deprotonated forms, respectively.

[M2-] = ___ M

[HM-] = ___ M

[H2M] = ___ M

A 9.10-g sample of solid MnCl2·4H2O was heated such that the water turned to steam and was driven off. Assuming ideal behavior, what volume would that steam occupy at 1.00 atm and 100.0 °C?

You are titrating 25 mL of 0.25 M Ascorbic Acid solution ith 0.15 M NaOH. Ascorbic Acid is an organic diprotic acid, H2A, that is found in many natural materials. Ka1 = 7.94 x 10^-5 and Ka2 = 1.62 x 10^-12. What is the a) initial pH, b) at the 1st equivalence point, c) the 2nd equivalence point, and d) after 27.5 mL of NaOH have been added?

In the precipitation reaction Na₂(C₂O₄)^2- (aq) + CaCl₂ (aq) -----> Ca(C₂O₄) (s) + 2NaCl (aq), how do I determine how many grams of the reactants I need to yield 5 grams of the precipitate?

The active ingredient in a zinc nutritional supplement is ZnSO4·7H2O (molar mass = 287.58 g/mol). Ten zinc tablets containing a mix of the active ingredient and an inactive filler were ground and mixed together thoroughly. The total mass of these ten tablets was 11.890 g. A 2.242 g sample of the finely ground tablets was dissolved in an acidic solution. The solution was neutralized with ammonia and subsequently warmed in a water bath. Addition of (NH4)3PO4 to the solution resulted in the precipitation of ZnNH4PO4. The precipitate was filtered and dried, then ignited to produce 0.180 g of Zn2P2O7 (molar mass = 304.76 g/mol).

1- What is the mass percent of ZnSO4·7H2O in each tablet?

2 and 3- What is the average mass of the active ingredient ZnSO4·7H2O and inactive filler in each tablet?

Determine the thermochemical equation for the oxidation of one mole of sucrose by a biological system.   (That means write a balanced chemical equation AND its enthalpy of reaction.)

Is the reaction gaining or losing entropy, S? Prove your answer with a calculation.

Determine the energy generated by eating one serving of Jelly Bellies, NOT from the package calorie list, but by calculating based on the grams of sucrose per serving of Jelly Bellies.