Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that has a 0.100 M concentration of NH3(aq) and a 0.100 M concentration of NH4Cl(aq).

Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

On a second question,

500.0 mL of 0.100 M NaOH is added to 615 mL of 0.250 M weak monoprotic acid (Ka = 4.91 × 10-5). What is the pH of the resulting buffer?

A 1.00 liter solution contains 0.51 M nitrous acid and 0.38 M sodium nitrite. If 25.0 mL of water are added to this system, indicate whether the following statements are TRUE (T) or FALSE (F). (Note the the volume MUST CHANGE upon the addition of water.)

A. The concentration of HNO2 will increase.

B. The concentration of NO2- will remain the same.

C. The equilibrium concentration of H3O+ will remain the same.

D. The pH will remain the same.

E. The ratio of [HNO2] / [NO2-] will increase.

A 1.00 liter solution contains 0.39 M ammonia and 0.30 M ammonium nitrate.

If 0.15 moles of nitric acid are added to this system,
indicate whether the following statements are TRUE (T) or FALSE (F).

(Assume that the volume does not change upon the addition of nitric acid.)

A. The number of moles of NH₃ will increase.

B. The number of moles of NH₄⁺ will remain the same.

C. The equilibrium concentration of H₃O⁺ will increase.

D. The pH will decrease.

E. The ratio of [NH₃] / [NH₄⁺] will remain the same.

Part A) A 0.5865-g sample of lactic acid (HC3H5O3) is burned in a calorimeter whose heat capacity is 4.812 kJ/°C. The temperature increases from 23.10 °C to 24.95 °C. Calculate the heat of combustion of lactic acid per mole.

Part B) The enthalpy of reaction for the combustion of C to CO₂ is –393.5 kJ/mol C, and the

enthalpy for the combustion of CO to CO₂ is –283.0 kJ/mol.

Calculate the enthalpy for the combustion of C to CO:

Part C) Carbon occurs in two forms, graphite and diamond. The enthalpy of the combustion

of graphite is –393.5 kJ/mol and that of diamond is –395.4 kJ/mol

C (s, graphite) + O₂(g) --> CO₂ (g)   

C (s, diamond) + O₂(g) --> CO₂ (g)   

Calculate for the conversion of graphite to diamond:

∆H = ____ kJ

Chromium (III) oxide, often called chromic oxide, has been used as green paint pigment, as a catylistin organic synthesis, as a polishing powder, and to make metallic chromium, One way to make chromium (III) oxide is by reacting sodium dichromate, Na2Cr2O7 with ammonium chloride at 800 to 1000 degrees celcius to form chromium (III) oxide, sodium chloride, nitrogen and water.

a) write a balanced equation for this reaction

b) What is the minimum mass, in megagrams, of ammonium chloride necessary to react completely with 275 Mg of sodium dichromate, Na2Cr2O7?

c) What is the maximum mass, in megagrams, of chromium (III) oxide that can be made from 275 Mg of sodium dichromate, Na2Cr2O7, and excess ammonium chloride?

d) If 147Mg of chromium (III) oxide is formed in the reaction of 275 Mg of sodium dichromate, Na2Cr2O7, with excess ammonium chloride, what is the percent yeild?

At 1 atm, how much energy is required to heat 75.0 g of H2O(s) at –10.0 °C to H2O(g) at 137.0 °C?

Use data from Appendix C to calculate the equilibrium constant, K, and ΔG∘ at 298 K for each of the following reactions.

H2(g)+I2(g)⇌2HI(g)
Calculate ΔG∘.

Express your answer to four significant figures and include the appropriate units.

Part A

H2(g)+I2(g)⇌2HI(g)
Calculate ΔG∘.

Express your answer to four significant figures and include the appropriate units.

Part B

Calculate the equilibrium constant, K.

Express your answer using two significant figures.

Part C

C2H5OH(g)⇌C2H4(g)+H2O(g)
Calculate ΔG∘.

Express your answer to two significant figures and include the appropriate units.

Part D

Calculate the equilibrium constant, K.

Express your answer using two significant figures.

Part E

3C2H2(g)⇌C6H6(g)
Calculate ΔG∘.

Express your answer to four significant figures and include the appropriate units.

Part F

Calculate the equilibrium constant, K.

Express your answer using one significant figure.

DIRECT METHOD EXAMPLE: A buffer was created by mixing 10 mL of a 0.10 M hydrofluoric acid solution with 25 mL of a 0.20 M sodium fluoride solution. What is this solution’s pH? Do you expect it to be a ‘good’ buffer with a high buffer capacity or a ‘poor’ buffer with low capacity? The Ka of hydrofluoric acid is: 7.2 x 10-4. Show work, thank you.

Phenol is soluble in NaOH (aq) and not NaHCO3 (aq) while benzoic acid is soluble in both solutions. Explain how a mixture of phenol, benzoic acid, p-nitroaniline and anthracene can be separated by extraction. PLEASE Dont forget to talk about anthracene!

Write and balance equations for the following acid-base neutralization reactions.

Part A

CsOH(aq)+H2SO4(aq)→

Express your answer as a chemical equation. Identify all of the phases in your answer.

Part B

Ca(OH)2(aq)+CH3CO2H(aq)→

Express your answer as a chemical equation. Identify all of the phases in your answer.

Part C

NaHCO3(aq)+HBr(aq)→

Express your answer as a chemical equation. Identify all of the phases in your answer.

2.Calculate the molar masses of the following substances.

Part A

Aluminum sulfate, Al2(SO4)3

Part B

Sodium bicarbonate, NaHCO3

Part C

Diethyl ether, (C2H5)2O

Part D

Penicillin V, C16H18N2O5S

The products of our reaction (1- and 2-heptene) can form peroxides upon standing in air for a prolonged period of time. Why is 1-heptene more likely to form peroxides than heptane?

At a pressure of 907 mbar , what would the height of the mercury in the column of a mercury barometer?

also

A closed container is filled with oxygen. The pressure in the container is 205 kPa . What is the pressure in millimeters of mercury?

how does atomic radius, ionization energt, or electron affinity explains the solubility of ions?

A mole of air is sampled from the atmosphere when the atmospheric pressure is 765 mmHg, the temperature is 25 C, an relative humidity is 75%. The sample of air is placed inside a closed container and heated to 135 C and then compressed to 2 atm. What are the relative humidity, the humidity, and the mole fraction of water in the compressed air?

What mass of ammonium chloride should be added to 2.55 L of a 0.150 M NH3 in order to obtain a buffer with a pH of 9.60?