± Enthalpy of Reaction: State and Stoichiometry

Use the data below to answer the questions.

Keep in mind that the enthalpy of formation of an element in its standard state is zero

Part D

Suppose that 0.290 mol of methane, CH4(g), is reacted with 0.440 mol of fluorine, F2(g), forming CF4(g) and HF(g) as sole products. Assuming that the reaction occurs at constant pressure, how much heat is released?

Express your answer to three significant figures and include the appropriate units

Determine the pH of an HNO2 solution of each concentration. In which cases can you not make the simplifying assumption that x is small?

a. 0.250 M
b. 0.0500 M
c. 0.0250 M

How many grams of solid ammonium bromide should be added to 1.50 L of a 0.118 M ammonia solution to prepare a buffer with a pH of 9.930 ? grams ammonium bromide = ? g

How many grams of solid ammonium chloride should be added to 1.00 L of a 0.291 M ammonia solution to prepare a buffer with a pH of 8.340 ?
grams ammonium chloride =? g

What is the purpose of rinsing platinum electrodes with acetone or ethyl alcohol?

Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction: SO2(g)+12O2(g)→SO3(g) : C(s)+H2O(g)→CO(g)+H2(g) : N2O4(g)+4H2(g)→N2(g)+4H2O(g)

These are reactions I did in my lab. I need to write the molecular, total ionic, and net ionic reactions for them. Even after watching Khan Academy and using my book, I was still unsure, so I asked the professor and he said every single one was wrong and told me to figure it out.

I know this is long, but I would really appreciate it. I need the molecular, total ionic, and net ionic equations for all of them. It's not making sense to me. Thank you.

a. HCl + CaCO₃ ­ → HCO₃ + CaCl₂

b. NaOH + HCl → NaCl + H₂O

c. NaOH + NH₄Cl → NaCl + NH₄OH

d. FeCl₃ + NaOH → NaCl + Fe(OH)₂

e. CoCl₂ + FeCl3 → NR

f. AgNO₃ + CoCl₂ → AgCl + Co(NO₃)₂

g. Na₂CO₃ + AgNO₃ → NaNO₃ + Ag₂CO₃

h. CuSO₄ + Na₂CO₃ → CuCO₃ + NaSO₄

i. CuSO₄ + BaCl₂ → CuCl + BaSO₄

j. NaSO₄ + CuSO₄ → NR

k. NiCl₂ + Na₃PO₄ → NiPO₄ + NaCl

For the reaction 2Co3+(aq)+2Cl−(aq)→2Co2+(aq)+Cl2(g). E∘=0.483 V what is the cell potential at 25 ∘C if the concentrations are [Co3+]= 0.456 M , [Co2+]= 0.451 M , and [Cl−]= 4.50×10−2 M and the pressure of Cl2 is PCl2= 2.30 atm ?

1.14 mol sample of argon gas at a temperature of 12.0 °C is found to occupy a volume of 30.0 liters. The pressure of this gas sample is ______ mm Hg.

A sample of krypton gas collected at a pressure of 385 mm Hg and a temperature of 284 K has a mass of 94.7 grams. The volume of the sample is _____L.

A 0.238 gram sample of hydrogen gas has a volume of 973 milliliters at a pressure of 2.06 atm. The temperature of theH₂ gas sample is _____°C

HClO is a weak acid (Ka = 4.0 × 10–8) and so the salt NaClO acts as a weak base. What is the pH of a solution that is 0.024 M in NaClO at 25 °C?

An aqueous solution of glycerin, 7% by weight, is prepared. The solution is found to have a density of 1.0149 g/mL. The density of pure glycerin (MW=92.0473) is 1.2609 g/mL. What is the molarity and molality concentration of the solution?

A 50.0 -mL sample of 0.50-M acetic acid, CH3COOH, is titrated with a 0.150M NaOH solution. Calculate the pH at equivalence point. (Ka=1.8x10^-5)

How do oxides, peroxides, and superoxides react? Please go into detail.

Devise a cell for which the full cell reaction is:   Ag⁺(aq) + Br⁻(aq) → AgBr (s)

a. What is the cell emf at 25°C?

b. Calculate DG˚rxn from both E° and standard Gibbs energies of formation.

c. Calculate the equilibrium constant.

d. Calculate the solubility, S, of AgBr.

Phosphorous acid, H3PO3(aq), is a diprotic oxyacid that is an important compound in industry and agriculture.

pKa1 = 1.30

pKa2 = 6.70

Calculate the pH for each of the following points in the titration of 50.0 mL of a 1.5 M H3PO3(aq) with 1.5 M KOH(aq).

A) before any addition of KOH

B) after addition of 25.0 mL of KOH

C) after addition of 50.0 mL of KOH

D) after addition of 75.0 mL of KOH

E) after addition of 100.0 mL of KOH

Determine the composition of each of the following cobalt alloys. (Percent by mass)

A). One-third of the Co atoms are replaced by Zn atoms.

B). One-eighth of the Co atoms are replaced by Ti atoms.

C). One-third of the Co atoms are replaced by Zn atoms and one-sixth of the Co atoms are replaced by Ti atoms.