CHEM 1040 Lecture Notes - Lecture 28: Nitrous Acid, Rice Chart, Chemical Equation

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19 Nov 2017

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Remember that this is a basic buffer system, as shown by the ph. Without an ice table, think about what happens to the equilibrium when something is added to the right side. The equilibrium will shift to the left, meaning that the concentration of oh- goes down, therefor [h3o+] increases. Remember that this is an acidic buffer system, as shown by the ph. Write out the hh equation for the reaction, and fill in the ph and pka. Then solve for the ratio. ph = pkhno2 + log [no2. Now, sub in the number of moles of hno2, and solve for no2. For a buffer to be basic, there must be a base and a conjugate acid. The buffer equation will be in the form. The hh equation will be in the form. The hh equation will be in the form ph = pkhac + log [ac.

Related Questions

CHM 1360 Spring 2021 Name __________________________

Lab 1 Buffers Worksheet

Type your answers to the following questions. Make sure to use complete sentences. For images that need to be hand drawn, take a digital picture of your image and insert it into your worksheet.

(0.5 point) Insert your lab notebook image of the pH plot from your preparation of the acetate buffer.
(1.5 point) Draw the Lewis structures for acetic acid (CH₃COOH) and acetate (CH₃COO^-). On each structure, label the carboxylic acid or carboxylate functional group. Also, label the acidic hydrogen (if it has one).
(2 points) In the first experiment, you prepared a buffer by combining solutions of acetic acid and sodium acetate.
1. (1 point) Write the chemical equation for the equilibrium of acetic acid and acetate in water. Include the states of the reactants.
2. (1 point) Write a net ionic equation that shows how this buffer neutralizes added acid (HCl).
3. (1 point) Write a net ionic equation that shows how this buffer neutralizes added base (NaOH).
In the second part of Experiment 1, you added water to the buffer solution which diluted it by a factor of two.
1. (1 point) Write the chemical equation for the equilibrium of acetic acid and acetate in water. Include the states of the reactants.
2. (0.5 point) Did the pH of the solution change? Briefly explain your observation.
3. (0.5 point) Which buffer solution would have a greater buffer capacity, your acetate buffer before the extra water was added, or the buffer solution that had been diluted? Explain.
4. (0.5 point) For your diluted acetate buffer, if you then added 50 mL of 0.50 M H₂SO₄ to the solution how would you expect the pH to change? Explain your answer.

(1 point) Which of the following could be added to a solution of monobasic dihydrogen phosphate (KH₂PO₄) to produce a buffer? Briefly explain your answer(s).

Dibasic monohydrogen phosphate hydrochloric acid sodium chloride

A) hydrochloric acid only
B) sodium chloride only
C) Dibasic monohydrogen phosphate (K₂HPO₄) only
D) Dibasic monohydrogen phosphate (K₂HPO₄) and sodium chloride

(a) (1 point) The average human contains 5.0 liters of blood having a pH of 7.35. Calculate the number of moles of H₃O⁺ at 25 ^o (Report the correct number of SigFigs in your final answers).

(b) (1 point) If a person’s blood pH falls to 7.25, how many more moles of H₃O⁺ are present at 25 ^oC?

(a) (0.5 point) Write a chemical equation to summarize what was happening in the phenol red solution in the flask in Experiment 2.

(b) (0.5 point) Does exhaling CO₂ help raise or lower the pH of the blood? Explain, using the equation you wrote for part (a).

(1 point) At pH 3.0, the amino acid glycine has the structure shown here. Draw the structure of this molecule at pH 12.0.

peachhamster190

1. Determine the amount of solute in the following samples:

500 ml of 0.2 M KI (potassium iodide)

220 ml of 0.03 M H2SO4 (sulfuric acid)

2.5 l of 0.1 M MgNO3 (magnesium nitrate)

1 ml of 5 M HCl (hydrochloric acid)

This problem requires that you know what molarity (M) is. M (molarity) = # of moles of solutes / Liter of solution. You are given the volume. You should be able to obtain moles of solutes. Your answers can be in moles or grams (either one will be acceptable).

2. How many ml of 0.1 M HCl would be required to titrate 35 ml of 1 M NaOH to the end point?

This is an acid/base reaction.

1) First, write out the balanced chemical reaction for HCl + NaOH.

2) Second, figure out the number of moles of NaOH in 35 ml of 1 M NaOH.

3) How many moles of HCl is required for completely reacting with the moles of NaOH in Part 2).

3. What is the pH of a 0.03 M solution of the strong base NaOH?

1) This question requires that you know pH = - log [H₃O⁺], or simply as pH = - log [H⁺] (to make it easier).

2)So, you have to know how to use your scientific calculator to do log function (check Youtube).

3) This question also requires that you know: pOH = - log [OH^-].

4) This question also requires that you know: [H₃O⁺][OH^-] = 1.0 x 10^-14 or pH + pOH = 14

5) First step, determine the concentration of OH^- in 0.03M NaOH when it dissociates or breaks up into Na⁺ and OH^-.

6) This will give you [OH^-]. You can plug this into pOH = - log [OH^-] to get pOH.

7) Once you get pOH, then use (pH + pOH = 14) to get pH.

4. Balance the chemical reactions shown below and then write equilibrium expressions for each. All reactants and all products are in the gas phase.

CO + F₂ ------> COF₂

CH₄ + O₂ ------> CO₂ + H₂O

N₂O₄ -----> Br₂ + NO

BrNO -----> Br₂ + NO

1)This problem requires that you know how to balance chemical equations.

2)After you balance the equation, you need to know the equilibrium expression

5. Determine the oxidation states of each element comprising the following ionic compounds:

KClO₄

NaMnO₄

Sr(NO₃)₂

NaHCO₃

CH₄

HERE IS HOW THIS IS GOING TO WORK! IF YOU ANSWER THE QUESTIONS IWILL GIVE YOU THE 3K POINTS + MORE AFTER I REPOST IT.

2. The amount of heat involved in the synthesis of 1 mole of acompound from its elements, with all substances in their standardstates at 25*C, is called _________.

3. What is a valid unit for specific heat?

4. Use Hess's Law to find the heat of reaction in the examplebelow.

N2O4 (g) ----> 2NO2 (g)

Given that:

N2O4 (g) ----> N2 (g) + 2O2 (g) (Delta H =-9.7kJ)

2NO2 (g) ----> 2O2(g) + N2(g) ( Delta H= -67.7kJ)

5. Use Hess's Law to find the heat of reaction in the examplebelow. (Example doesn't exist btw.)

6. (Delta H) for the formation of rust (Fe2O3) is -826 kJ/mol. Howmuch energy is involved in the formation of 5 grams ofrust?

7. How many kilocalories of heat are required to raise thetemperature of 50g of aluminum from -5*C to 35*C? (Specific heat ofAluminum = 0.21 cal/g*C)

8.Calculate the (Delta H) for this reaction:

Zn(s) + Cu (2+ ion)(aq) ---> Zn(2+) + Cu(s)

(Delta H) for Cu(2+) = +64.4 kJ/Mol; (Delta H) for Zn(2+) = -152.4kJ/mol

9. The following equation shows the reaction that occurs whennitroglycerine explodes.

4C3H5O9N3 ----> 12CO2 + 6N2 + O2 +10H2O + 1725 Kcal

Is this reaction exothermic , endothermic, a combustion reaction ,or a combination reaction?

10. What does it mean for ammonia, (NH3) to have a (Delta H f) =-46 kJ/mol?

(for example: Define heat of formation. What does a negative heatof formation mean? what do the units of kJ/mol mean?)

11. What is the maximum amount of KCl that can dissolve in 500g ofwater?

(solubility of KCl is 34 g/ 100g of water at 20*C)

12.List the ways(operations) that can help make a substancedissolve faster in a solvent?

13. If a crystal added to an aqueous solution causes many particlesto come out of solution, the original solution was (saturate,unsaturated, supersaturated).

14. What is the number of moles of solute in 165 mL of a 0.82 Msolution?

15. What mass of NaCl is needed to make 350 mL of a 1.00 Msolution?

16. Colligative properties depend upon...

17. If one mole of each of these solutes in added to the sameamount of water, which solution has the highest boiling point?(glucose, aluminum sulfate, magnesium acetate, copper (I)chloride)

18. When an acid reacts with a base, what compounds areformed?

19. If the [H+] in a solution is 1x10^(-13) mol/L, what is the[OH-]?

20. If the [OH-] = 1x10^-6 mol/L, what is the pH of thesolution?

21. For a solution to be considered acidic what must be thehydrogen-ion concentration?

22. Which of the following represents a Bronsted-Lowry conjugateacid-base pair?

a) SO3(2-) and SO2 b) CO3(2-) and CO c) H3O and H2 d) NH4(+) and NH3

23. With solutions of "strong" acids and "strong" bases, the word"strong" refers to ...

24. What are the products of Al(OH)3 + H2CO3?

25.What is the concentration of hydrochloric acid if 5.0 mL of acidis neutralized by 30.0 mL of 2.00M sodium hydroxide.

26. At equilibrium, what is the rate of production of reactantscompared with the rate of production of products?

27. What is the equilibrium constant for the following reaction2SO3 ---> 2SO2 + O2

28. How does an increase in pressure affect the following reaction?2SO3 (g) --> 2SO2(g) +O2(g)

29.What stresses would shift the reaction to the right?

2SO3(g) ==> 2SO2(g) + O2(g)

30. The Keq of a reaction 4.9 x 10^(-7). Are products or reactantsfavored at equilibrium?

31. In which of these systems is the entropy decreasing?

a) air escaping from a tire b) snow melting c) a gas condensing d) salt dissolving inwater

32. If an atom is reduced in a redox reaction, what must occur toanother atom in the system?

33. Identify the oxidizing agent in the following reaction: 2Na + S---> Na2S

34. What are transferred in an oxidation -reductionreaction?

35. Give the oxidation number for each atom in KMnO4.

36. Which atom has a change in oxidation number of +4 in thefollowing reaction?

K2Cr2O7 + H2O + S ----> KOH + Cr2O3 +SO2

37. What is the oxidation number of sulfur in each of the following:

a. SO3 c.SO2(2-)

b. Na2SO4 d. S2O4 (2-)

38.Fe(3+) ----> Fe represents oxidation, reduction, orhydrolysis?

39. When the half reactions Br2+ 2e- -----> 2Br- and Na---->e- + Na(+) are combined the balanced redox equation is_____________________ ( WRITE the BALANCED REDOX eq)

40. To balance the oxygen and hydrogen for a redox reaction thattakes place in basic solution, it is necessary to use whichsubstance?

41. What particle completes this nuclear equation? 55/25 Mn + 2/1 H====> _____ +2 1/0 n

42. The half-life of tungsten-182 (182/74 W) is 1.1x10^(17) years.How long would it take for a 376.2 kg sample to decay until only123.0 grams remain?

43. After 3 days, the quantity of certain radioisotope is reducedfrom 13.6 grams to 1.9 grams. Calculate the half-life of theisotope.

44. What is the name of the compound having the formulaC8H18.

45. What is the name of the following compound:

CH3---CH2----CH---CH2--C

I \

CH3 OH

46. What is an isomer? Give an isomer of hexane (C6H14) and drawit's structure.

47. What is the name of the hydrocarbons with double covalentbonds?

48. Draw the stucture for 3-methylbutanoic acid.

49. Draw the structure for methylbenzene?

50. What is the name of the following compound:

CH3----C-----CH3

CH3

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CHEM 1040 Lecture Notes - Lecture 28: Nitrous Acid, Rice Chart, Chemical Equation

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