2. Four unidentified solutions of equal concentration (0.1mol/L) were prepared by chemistry students who wereinvestigating the properties of acids and bases.SolutionRed litmusBlue litmuspHConductivitBlueNo change13.2Very high2No changeRed3.5Weak3No changeRed1.8Very high4BlueNo change10.7WeakIdentify the acids and the bases in the list above.b. Classify the acids and the bases as being weak or strong withsupporting information.Suggest another test that could be used to determine therelative strengths of the acids.

The acidity of a solution is dependant on the concentration of protons or hydronium ions in the…

2. Four unidentified solutions of equal concentration (0.1 mol/L) were prepared by chemistry students who were investigating the properties of acids and bases. Solution Red litmus Blue litmus pH Conductivit Blue No change 13.2 Very high No change Red 3.5 Weak 3 No change Red 1.8 Very high Blue No change 10.7 Weak a. Identify the acids and the bases in the list above. b. Classify the acids and the bases as being weak or strong with supporting information. c. Suggest another test that could be used to determine the relative strengths of the acids.

2. Four unidentified solutions of equal concentration (0.1 mol/L) were prepared by chemistry students who were investigating the properties of acids and bases. Solution Red litmus Blue litmus pH Conductivit Blue No change 13.2 Very high No change Red 3.5 Weak 3 No change Red 1.8 Very high Blue No change 10.7 Weak a. Identify the acids and the bases in the list above. b. Classify the acids and the bases as being weak or strong with supporting information. c. Suggest another test that could be used to determine the relative strengths of the acids.

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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2. A. If 100 mls of 0.03 M HCI is added to 400 mls of 0.5 M glycine buffer at pH 10.4, what is the resultant pH? (pK1 for Gly= 2.2, Pk2=9.4) Gly.4L X.5mol/L= .2 mol HCI.1LX.03mol/L = .003mol Glyº .02mol +.003 mol .023mol [HA] = .023/.5L =.046M, [A-] =.177/.5L = .354M pH = pka +log [A-]/[HA] pH = 9.4 +log.354/.046 = 10.3 [HCI] = [H+] = .003mol/.5L = .006M pH =2.2 Gly + H+ .18mol -.003mol .177mol end start B. What would the pH be if the same amount of HCl as in part A was added to 400 mls of water?
3) Ammonia, NH3, is toxic to a wide range of aquatic organisms including snails, insects, and fish. The ammonium ion, NH4", is much less toxic since the cation does not diffuse rapidly across cell membranes. The US EPA limit for total ammonia in natural waters is 1.9 mg/L at pH 7. a. What is this limit in molar units? b. What is the concentration of NH3 at pH 7? c. What is the concentration of NH3 at pH 6? d. Why is the EPA limit for total ammonia dependent on the water pH?
4. Some antacids will generate carbon dioxide, CO2, when they neutralize the acid in gastric juice. Write the net ionic equation for the reaction of the antacid containing the anion carbonate, CO3 , or the anion bicarbonate, HCO3, with acid (H+). 5. Write the net ionic equation for the neutralization of the bases, magnesium hydroxide, Mg(OH)2, and aluminum hydroxide, Al(OH)3, found in Maalox, for example, with acid (H*).
1. Polar Covalent Bonds a. Draw one water molecule. b. Indicate which bonds are polar covalent bonds by using a solid red line for each of those bonds. c. Label the partial charges.
Based on the Henderson-Hasselbalch equation (shown below), calculate the pH when half of a solution of acetic acid is dissociated to acetate (the pKa of acetic acid is 4.76). A. 1.00 B. 3.76 C. 4.76 D. 5.76
9. Find the final concentration as a percent (w/v) of dextrose when 75 mL dextrose 50 % (w/v), 50 mL of sodium chloride 0.9 % (w/v), and 100 mL of dextrose 5 % (w/v) sodium chloride 0.45 % (w/v) solution are mixed together.
Bicarbonate ion (HCO3) is a type of the following: O a. Acid O b. Base O c. Buffer O d. Salt Oe. None of the Above
3. How will you prepare 500 ml of 0.750 M citrate buffer with pH of 4.25 from solid citric acid (C6H8O7) and solid sodium citrate (Na3C6H5O7). The Ka of citric acid is 7.40 x 10-4 . Given: • (Na3C6H5O7) solid sodium citrate = conjugate base in molarity [? −] • (C6H8O7) solid citric acid = weak acid in molarity [??] • 7.40 × 10−4 ?? of citric acid = ??? (acid-dissociation constant) • 500 ml of 0.750 M citrate buffer
II. Lipids from an organic sample are extracted separately by column chromatography using the ff eluants: 1st eluant - chloroform: methanol: water (6:3:1) 2nd eluant - methanol: chloroform (9:1)3rd eluant – petroleum ether: ethyl ether (1:1) Test results for each eluate are tabulated below. Identify the possible lipid present in each eluate. Based on the results above, _________________ 1. _________________ 2. _________________ 3. _________________ 4. _________________ 5. answer the following questions: What visible positive result for test reagent no. 5?Give the name of chemical characterization test for test reagent no. 3?What class of lipids will give a visible positive result on the test mentioned in question no. 2?Give the chemical name of the product formed after giving a positive result for test reagent no. 1?Test reagent no. 1 is used to test for what organic compound?
12. What is the pH of a solution in which [OH] = 0.000005 M? )5.3 8.7 O 5 x10
8. What mass of solute is needed to prepare each of 1.00 L of 0.125 M K2SO4 solutions? (2 Points) 21.8 g K2SO4 218.0 g K2SO4 2.816 g K2SO4 28.16 g K2SO4
2. 3. Perform all the calculations necessary for the volume of stock solution or water, in mL, needed to make the dilute solutions listed below. a. b. C. Make: 200 mL of 30% Ethanol dilute solution Stock Volume needed (mL) 95% Ethanol Reagent water Make: 100mL of .09%NaCL Stock 1% NaCl Reagent water 30% SDS 3 M NaOH Make: 100 mL of a 3% SDS and 0.5 MNaOH dilute solution as follows: Stock Volume needed (mL) Reagent water 200 mL Total 1% Lactose 1% Dextrose Volume needed (mL) 100 mL Total Calculate the grams of chemical needed for each stock listed below. Concentration of Stock to Prepare Volume of Stock Needed 1% Sucrose 100 mL Total 10 mL 20 mL 25 mL Amount of chemical Needed (in grams) Your instructor will have you make ONE of the above solutions-ask your instructor which solution to make.