50.0mL of .500M NaOH is added to 25.0mL of .500M HCL in a calorimeter BOth are at an initial temperature of 25 C ans final temperature is 27.21 C. Assume the mass of the final solution is 76.0 g and the Cs of the solution is 4.18 J/gC. what is the value of q for water, what is the value of q for the reaction, what is the change of H of the reaction in kj/mol?

What would be the effect of each of the following on the calculated molar mass of the solute?

1. some cyclohexane evaporated while the freezing point of pure cyclohexane was being measured.

2. some cyclohexane evaporated after the solute was added.

3. some unknown power was still left one the weighing paper.

4. a foreign solute was already present in the cyclohexane?

5. the thermometer is not calibrated correctly. it gives a temperature that is 1.5 C too low at all temperatures.

6. solution didn't freeze completely.

please help me answer these. thank you! i promise to rate you :)

BCl3is a monomer that is a gas at room temperature while the analogous Al compound is the Al2Cl2 dimer with 2 chlorides bridging between the two Al's. Draw Lewis structures of each compound and suggest a reason for the significant differences in the strucutres. Note that it is important that Al and B obey the ocetet rule in your Lewis strucutures.

13) Calculate the change in pH when 8.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq).

delta pH=?

Calculate the change in pH when 8.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

delta pH=?

What is the pH of a solution that results when 0.012 mol HNO3 is added to 610.0 mL of a solution that is 0.26 M in aqueous ammonia and 0.46M in ammonium nitrate. Assume no volume change. (Kb for NH3 = 1.8 × 10–5.)

a. 8.96

b. 9.56

c. 5.04

d. 9.01

e. 4.44

When a cell reaction reaches equilibrium, E = 0. E = 0. both E and E = 0. neither E nor E = 0.

Calculate analytical concentration for each of the following solutions:

a) HCl solution, pH = 1.34

b) Acetic acid solution, pH = 4.31

c) Sulfuric acid solution, pH = 2.21

d) Potassium hydroxide solution, pH = 12.21

Acetic acid: pKa = 4.76

Sulfuric acid: pKa,1 = strong, pKa,2 = 1.99

In water, [H3O+][OH–] = 1.00 ! 10–14

Ignore the effect of ionic strength.

Calculate [H3O+] and [OH−] for each of the follo...

pH= 8.56

pH= 11.20

pH= 2.84

A.

Calculate [H3O+] in the following aqueous solution at 25 ?C: [OH?]= 1.6×10^?9 M .

Express your answer using two significant figures.

B.

Calculate [H3O+] in the following aqueous solution at 25 ?C: [OH?]= 3.0×10^?2 M .

Express your answer using two significant figures.

C.

Calculate [H3O+] in the following aqueous solution at 25 ?C: [OH?]= 7.0×10^?12 M .

Express your answer using two significant figures.

4. A puddle of coastal seawater, caught in a depression formed by some coastal rocks at high tide, begins to evaporate as the tide goes out. If the volume of a puddle decreases to 23% of its original volume, what is the sodium chloride concentration if it was initially 0.449 M?

5. Iron (II) can be precipitated from a slightly basic aqueous solution by bubbling oxygen through the solution, which converts Fe (II) to Fe (III):

                  4 Fe(OH)⁺ (aq) + 4 OH^- (aq) + O₂(aq) + 2H₂O (L) ? 4 Fe(OH)₃ (s)

How many grams of oxygen are needed to precipitate all of the iron in 75 mL of 0.090 M Fe(II)?

Calculate the activity at 25 degrees Celsius of NACl(s) at 1, 10, 100, and 1000 bar. The density of NaCl at 25 degrees Celsius and 1 bar is 2.16 (g/cm3).

If the Ksp of PbI₂ is 7.1 x 10^-9   will precipitation occur when 10 mL of 1.0 x 10^-4 Pb(NO₃)₂ is mixed with 10 mL of 1.0 x 10^-3 M KI? (Show calculation)

Fresh orange juice containing 10 % solids and the balance water is fed to an evaporator to produce final product of concentrated orange juice containing 40% solids. A fraction of the fresh juice bypassed the evaporator to insure fresh taste. The juice that enters the evaporator at 10% is concentrated and leaves the evaporator at 60% solids, and the evaporator product stream is then mixed with the bypassed fresh juice to achieve the desired final concentration of 40 % solids. All percentages are in mass%. Draw and label a flowchart of this process and based on 100 lb/hr of the final 40% mass product. calculate the following flow rates in Lb/hr:

a. Fresh overall feed rate to the process

b. Flow rate of pure water leaving the evaporator and the bypass flow rate

Balance each of the following redox reactions occurring in basic solution.

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

H2O2(aq)+ClO2(aq)?ClO?2(aq)+O2(g)

Al(s)+MnO?4(aq)?MnO2(s)+Al(OH)?4(aq)

Cl2(g)?Cl?(aq)+ClO?(aq)