3.00 g of potassium hydroxide (KOH) pellets are put into a constant-pressure calorimeter containing 250 mL of water. The initial temperature of the water is 22.3°C. The mixture is then stirred until all of the KOH is dissolved. The final temperature of the solution is measured and recorded as 29.7°C. Calculate the heat of solution for potassium hydroxide (ΔH_soln). The specific heat capacity of the solution may be assumed to be the same as that of water since this is a dilute solution. Assume no heat loss from the calorimeter.

What mass of KOH do you need to dissolve to reach a final temperature of  38 °C?

A sample of a substance with the empirical formula XBr2 weighs 0.5210 g. When it is dissolved in water and all its bromine is converted to insoluble AgBr by addition of an excess of silver nitrate, the mass of the resulting AgBr is found to be 0.6586 g. The chemical reaction is XBr2 + 2 AgNO32AgBr + X(NO3)2

(a) Calculate the formula mass of XBr2. Formula mass XBr2 = g mol-1

(b) Calculate the atomic mass of X. Atomic mass X = g mol-1

A beaker with 105 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 7.40 mL of a 0.430 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.

Express your answer numerically to two decimal places. Use a minus ( − ) sign if the pH has decreased.

Cyclic voltammograms for a Fe(CN)₆^3- solution are obtained when the solution is stirred and when it is unstirred. Explain why the stirred cyclic voltammogram looks different from the unstirred one. Why is the signal noisy and consider what happens to the product when formed at the electrode.

Is the six-membered ring system in benzene particularly stable or unstable? Explain using chemical concepts

How will I find the pI for a non-ionizable amino acid?

The Separation of Three Organic Compounds by Acid, Base Reactions and Liquid, Liquid Extraction.

Okay, so we had solid benzoic acid, ethyl 4- aminobenzoate, and 9-fluorenone all dissolved in diethyl ether. We separated the basic component by adding 3M HCl, we separated the acidic component by adding 3M NaOH. I don't understand what happens here. To isolate the acidic solution, we added 6 M NaOH and used the vacuum to recover the solid. To isolate the basic solution we added 6M HCl. I did an experiment where a 1:1:1 mixture of Benzoic Acid solid (C6H5COOH), ethyl 4-aminobenzoate solid (C9H11NO2), and 9-fluorenone solid (C13H8O) was dissolved with methylene chloride. Then each component was extracted and tested. I need to come up with a proton transfer chemical reaction that represents what happened in each separation. First separation: HCl was added and two layers formed. aqueous layer was extracted and transfer to a clean container and methylene chlotide layer was left aside. NaOH was added dropwise to aqueouse layer extraction and vacuum filtration was used to extract/separate the basic component ethyl 4-aminobenzoate solid (C9H11NO2).

Results &Data:

1)Benzoic acid (Acid)

Table 1: Collected data from Benzoic acid

2) Benzoate (Base)

Table 2: Collected data from Benzoate.

3) 9-Fluorenone (Neutral)

Table 3: Collected data from 9-Fluorenone.

I need to find the theoretical and percent yield of each product, how many mg of each product is present. And also create 4 chemical reactions. Need help, Please help thankyou

Calculate the change in standard-state entropy for the following reaction that results in the formation of glucose:

6 CO2(g) +6 H2O(l) ⟶ 1 C6H12O6(s) + 6 O2(g)

(If applicable, coefficients of one have been included for clarity.)

Express your answer with the appropriate units. Use FOUR significant figures.

1. Complete Table 1 by calculating the volume of 2.0 mg/mL myoglobin, 6.0 M GuHCl, and 0.5 M phosphate buffer needed to make the 15 solutions needed for the experiment.

Describe the procedure you would follow to determine the concentration of Vitamin C in a sample if the volume of DCPIP required to reach the endpoint was more than the 25-mL flask could hold. Note the titration must still be carried out in the flask. Be sure to include any calculations you would need to perform.

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.