A student was given buffer solutions to calibrate the pH electrode that were labeled incorrectly. The pH's of both buffer solutions were actually lower than the pH's shown on the labels. Explain how such an error would affect the experimental result for the K_a of acetic acid.

2.The solubility of silver chromate (Ag2CrO4) is 2.22 x 10-3 g/100 mL.

a) What is the Ksp? Include the chemical equation and Ksp expression. MW (Ag2CrO4): 332 g/mol

b) What happens to the solubility of Ag2CrO4 in the presence of ammonia?

c) If 0.050 moles of silver nitrate are added, what is the solubility of Ag2CrO4?

How many grams of copper be deposited at the cathode of an electrolysis cell if an electric current of 15 mA is applied for 1.0 h through an aqueous solution containing excess Cu2+ ions? Assume the process is 100°0 efficient.

Question 1

Which of the following are variables that can be manipulated in a gas law equation? (Choose all that apply)

Group of answer choices

number of moles

temperature

pressure

mass

Question 2

True or False. According to Charles’s Law, if you have a balloon inside a car at noon during a hot summer day, the molecules inside of the balloon will cause the volume of the balloon to increase.

Group of answer choices

True

False

Question 3

Name the gas law. Volume and pressure are indirectly proportional. Volume will decrease if pressure increases, and volume will increase if pressure decreases.

Group of answer choices

Avagadro’s

Gay-Lussac’s

Charles’s

Boyle’s

Question 4

Name the gas law. Temperature and pressure are directly proportional. If temperature increases, pressure will increase as well.

Group of answer choices

Charles’s

Gay-Lussac’s

Avagadro’s

Boyle’s

Question 5

What effect would a decrease in temperature have on pressure, assuming that volume (T) and moles of gas (n) are kept constant?

Group of answer choices

Pressure would decrease.

Pressure would stay the same regardless of a change in temperature.

Pressure would increase

Question 6

Which temperature scale has NO negative values?

Group of answer choices

Farenheit

Digital

Kelvin

Celcius

Question 7

Calculate the number of moles of gas with a volume of 35.0 L at a temperature of 32°C and pressure of 1.20 atm.

Group of answer choices

10.5 mol

0.596 mol

Did you rearrange PV=nRT correctly for n?

Does your temperature value have the correct units?

1.68 mol

Question 8

What is the temperature (°C) of 5.20 moles of gas in a 40.0 L container with a pressure of 4.50 atm?

Group of answer choices

149°C

237°C

422°C

273°C

Question 9

Calculate the volume of 3.3 moles of gas with a pressure of 950 mmHg and temperature of 25 °C. (Hint: 760 mmHg = 1 atm)

Group of answer choices

5.4 L

0.02 L

11.8 L

64.6 L

Question 10

A balloon has a volume of 875 mL at STP. At what temperature will the balloon have a volume of 1.33 L at a pressure of 0.72 atm?

Group of answer choices

3.08°C

25.7°C

299°C

0.299°C

If you were to add 10.0mL of 0.10M sodium acetate solution, what is the amount of CH3COOH(mol), Amount of CH3COO-(mol), and the predicted pH by the Henderson-Hasselbalch equation?

Given:

Start with sodium acetate

Add HCl

Initial Burette reading: 6.70ml

Final Burette reading: 9.80mL

Amount of HCl added(mol): 3.1 x 10^-4 mol

Justify the phospholipid being the major component of the cell membrane. Be specific and complete.

Question

1) A 1.0 mL aliquot (sample) is taken from a 1.0L solution. Which of the following is/are true when comparing the 1.0 mL solution to the 1.0L solution? Choose all that are true.

-The molarity of the 1.0 mL solution is less than the molarity of the 1.0L solution

-The molarity of each is the same

-The number of moles of solute in each solution is the same

-The number of moles of solute in the 1.0mL solution is less than the number of moles of solute in the 1.0 L solution

2) 5.00 mL is withdrawn from a 1.00L solution of NaCl and diluted to 100.00 mL. If the concentration of the NaCl in the 100.00 mL solution is 0.033, what is the concentration of NaCl in the original 1.00 L solution?

3) What is used as a blank (reference/zero absorbance) for the analysis of the samples in the spectrophotometer?

-Deioniozed water

- Nothing-air

-Acetylsalicylic acid standard solution

- Iron(III) chloride solution

4) The acetylsalycylic acid - iron (III) complex appears violet in color. What color of light is used to measure the absorbance of the solution?

- red

- orange

- green

- blue

- violet

5) A calibration curve for absorbance versus the concentration of the chemical indicator crystal violet is found to have a slope of 48. If a sample of unknown concentration has an absorbance of 1.38, what is the concentration in the unknown sample?

Most of our discussion of transition metals has focused around them becoming positively charged ions. However, many of the transition metals will also become negatively charged ions. Using what you have learned from quantum mechanics and about electron configurations, predict which transition metals are most likely to form anions with a charge of -1 and explain the prediction.

Triethlyamine is added with deionized water, what is the chemical equation? Next, this solution is now neutralzied by adding HCL. What is the chemical equation and name of the salt? Finally, NaOH is added to the solution, what is the chemical equation showing the free amine? Please explain and show steps.

-- Consider a concentration cell. Two Ag-electrodes are immersed in AgNO3 solutions of different concentrations. When the two compartments have an AgNO3-concentration of 1 M and 0.1 M, respectively, the measured voltage is 0.065 V (note: T in not necessarily = 25°C ).

The electrochemical behavior of silver nanoclusters (Agn, with n the number of Ag atoms in the cluster) is investigated using the following electrochemical cells at 298 K:

I. Ag(s) | AgCl (saturated) || Ag+(aq, 0.01M) | Ag(s), E=0.170

II. (Pt electrode) Agn (s, nanocluster) | Ag+(aq, 0.01M) || AgCl (saturated) | Ag(s), with E = +1.030 V for Ag5 nanocluster and E = +0.430 V for Ag10 nanocluster

The standard reduction potential for Ag+ + e- → Ag, is E0 = +0.800 V.

The two nanoclusters Ag5 and Ag10-nanoclusters have standard potentials different from the potential of metallic bulk silver.

c. Calculate the standard potentials of Ag5 and of Ag10 nanoclusters. [for this part use Ksp(AgCl)=1.800·10-5;]

d. What happens, if you put the Ag10 nanoclusters and – in a second experiment – the Ag5 nanoclusters into an aqueous solution of pH=5? Estimate the consequences using the reduction potentials you calculated.

With the completion of the determinations of % potassium, % iron, and % oxalate in the crystals, you may calculate the % water. The percentage compositionof the crystals, K_xFe(C₂O₄)_y · zH₂O, has then been completely determined experimentally. The simplest formula (x,y,z) can now be calculated from the the percentage composition. Once the formula is know it is then possible to calculate the percent yield of product that was obtained in the preparation and purification of the crystals.

You have entered the following values :

From Part A:

Mass of K_xFe(C₂O₄)_y · zH₂O prepared : 6.000 g
Mass of FeCl₃ : 1.60 g

From Part B:

% Potassium in compound : 11.50 %
% Iron (from ion exchange & titration vs. NaOH) : 14.70 %

From Part C:

% Oxlate : 40.56 %

The questions below are part of the final analysis, they are due at the beginning of the next lab, Tue Mar 31 08:30:00 am 2020 (EDT).

Now, let's finish the calculation and the determination of the formula of the iron compound:

Calculate the % water of hydration :

Calculate the following for Fe³⁺:

Calculate the following for K⁺:

Calculate the following for C₂O₄^2-:

Calculate the following for H₂O

Using your chemical knowledge and literature references (don’t forget to include the references in your lab report and discuss possible sources of errors) answer the questions below:

Enter the simplest formula of the Iron Oxalate Complex Salt:

Now that the formula of the complex salt is known, the percent yield can be determined.

Calculate the moles of FeCl₃ used in preparation:

Calculate the theoretical moles of K_xFe(C₂O₄)_y · zH₂O:

Calculate the actual moles of K_xFe(C₂O₄)_y · zH₂O synthesized:

Calculate the percent yield:

A 110.1 gram sample of an unknown substance (MM = 189.50 g/mol) is cooled from 233.0 °C to 147.6 °C. (heat capacity of liquid = 1.62 J/g･°C; heat capacity of gas = 1.04 J/g･°C; ∆Hvap = 78.11 kJ/mol; Tb = 160.3 °C)

A. How much energy (in kJ) is absorbed/released to cool the gas?

B. How much energy (in kJ) is absorbed/released to condense the gas?

C. How much energy (in kJ) is absorbed/released to cool the liquid?

D. What is the total amount of energy that must be absorbed/released for the entire process?

Design a buffer that has a pH of 8.25 using one of the weak base/conjugate acid systems shown below.

How many grams of the chloride salt of the conjugate acid must be combined with how many grams of the weak base, to produce 1.00 L of a buffer that is 1.00 M in the weak base?

grams chloride salt of conjugate acid =

grams weak base =

15.) The gallbladder is an intriguing if often overlooked organ that stores bile for the liver in a variety of vertebrates. A biochemically interesting aspect of the gallbladder is that it is one of the few places in the body that regularly has a basic pH. To study enzymatic processes that occur there, appropriate pH conditions must be replicated. The complicating aspect is that the pH is not uniform throughout the entirety of the gallbladder system, where it can range from pH 7.6 to pH 8.5. Conveniently, the buffer range of the H(Tris)+/Tris conjugate pair overlaps well with this system, having a pKa of 8.02. This pKa is convenient to many biological systems, hence its use as a buffer for many experiments.a)What is the full buffer range of the H(Tris)+/Tris system?b)Describe the preparation of two Tris buffer solutions, one for the high end and one for the low end of the gallbladder pH. Make both buffers to a total buffer concentration of 0.110 M with a volume of 1 liter.