Exam 4- Chapter 8

3. Which of the following is a diprotic acid? A). HCl B). HNO3 C). H2SO4 D). H3PO4

C). H2SO4

19.In an aqueous solution the [OH-] is 1.0 x 10- 8M. What is the pH for this solution? A.pH=6 B. pH = 8 C. pH = 14 D. None of the above

A. pH= 6 pOH=-log10-8 =8 pH + pOH = 14 pH = 6

35. If the intensity of radiation 1 cm from a source is 60 mCi, what is the intensity 2 cm from the source? A). 10 mCi B). 15 mCi C). 270 mCi D). 2.7 Ci

B). 15 mCi 60 mCi = 22 = 15 mCi I2 12

Is the amount of hydronium(H30+) or hydroxide ions (OH-) that a buffer can absorb without a significant change in pH depends both its pH and its concentration.

Buffer capacity

7. What is the name of HNO2? ( NO2- , nitrite ion) A). Hydronitric acid B). Hydronitrous acid C). nitric acid D). nitrous acid

D). nitrous acid

11. Barium-122 has a half-life of 2 minutes. If 10.0 g of Ba-122 are produced in a nuclear reactor how much Ba-122 will remain 10 minutes after production ceases? A. 2.50 g B. 1.25 g C. 0.625 g D. 0.313 g

D. 0.313 g 1 t ½ = 2 min 10 min x 1 half-life = 5 half-lives ------------- 2 min 10 g x ½ x ½ x ½ x ½ x ½ = 0.3125 g

6. The pKa of acetic acid, HC2H3O2, is 4.75. What is the pH of a buffer in which [HC2H3O2] = 0.40 M and [NaC2H3O2] = 0.10 M? A). 4.15 B). 4.45 C). 5.75 D). 7.00

A). 4.15 pH = 4.75 + log 0.1 = 4.75 + (-0.6) = 4.15 --------- 0.4

24. Which of the following solutions can function as ideal buffer systems? A). A solution containing the equal amount of a weak acid and the salt of its conjugate base. B). A solution containing the equal amount of a strong base and the salt of its conjugate acid. C). BothAandB D). Neither A nor B.

A). A solution containing the equal amount of a weak acid and the salt of its conjugate base.

15. Given the following information determine which of these acids is the strongest acid? pKa for boric acid is 9.14 pKa of acetic acid is 4.75 pKa of phenol is 9.89 A). Acetic acid B). Boric acid C). Phenol D). All of the above have the same acidic strength.

A). Acetic acid

31. What is the product from the beta decay of xenon-131 ? A). Cs - 131 B). Te - 131 C). I - 131 D). Xe-131

A). Cs - 131 131 Xe ?+0e -1

10. What are the two bases in the following reaction? NH4+(aq) + HPO42- = NH3 + H2PO4- A). NH3 and HPO42- B). NH4+ and NH3 C). HPO42- and H2PO4- D). NH4+ and H2PO4-

A). NH3 and HPO42-

14. The position of the equilibrium favors CH3COO- + NH4+ CH3COOH + NH3 A). The position of the equilibrium favors the reverse reaction (shift to left). B). The position of the equilibrium favors the forward reaction (shift to right). C). Neither the forward nor the reverse reaction are favored at equilibrium. D). The position of equilibrium cannot be predicted from the given data.

A). The position of the equilibrium favors the reverse reaction (shift to left).

22. When an acid reacts with a base the reaction is called which of the following? A). neutralization B). precipitation C). redox D). single displacement

A). neutralization

37. The following equation is an example of _______. 1 n + 235 U 91 Kr + 142 Ba + 3 1 n + Energy 0 92 36 56 0 A). nuclear fission B). nuclear fusion C). BothAandB D). Neither A nor B

A). nuclear fission

7. 15O is a positron emitter. What isotope is formed when 15O emits a positron? A. 15N B. 14N C. 15F D. 14F

A. 15N 15O ? + 0e 8 +1 The atomic number 8 = ? + (1) ? = 7 (N) The mass number 15 = ? + (0) ? =15

10. What percentage of a radioactive sample remains after 4 half-lives? A. 6.25% B. 3.13% C. 1.56% D. 0.781%

A. 6.25% 100% x ½ x ½ x ½ x ½ = 6.25 %

When Pb-208 bombarded with Ni-64, a new element and six neutrons are produced. What isotope of the new element is produced by this reaction? A. Ds-266 B. Ds-272 C. Rf-266 D. Rf-272

A. Ds-266 208Pb + 64Ni ? + 6 1n 82 28 0 The atomic number of ? = 82 +28 = 110 (Ds) The mass number of ? : 208 + 64 = ? + 6 x (1) ? = 266

12. Which of the following gases is produced when an acid reacts with an active metal? A. H2 B. O2 C. N2 D. CO2

A. H2

10. The following species can be characterized as amphiprotic EXCEPT A. H2S B. H2O C. HCO3- D. HPO42-

A. H2S Amphiprotic A substance can act as an acid, and as a base H2S (acid) HS- (conjugate base) H2O (acid) OH- (conjugate base); or H2O (base) H3O+ (conjugate acid) HCO3-(acid) CO32- (conjugate base); or HCO3- (base) H2CO3(conjugate acid) HPO42- (acid) PO43-(conjugate base); or HPO4- (base) H2PO4- (conjugate base)

1. According to Arrhenius which species is associated with all acids? A. H3O+ B. OH- C. H2O D. All of the above

A. H3O+

13. Consider the following hypothetical acid-base reaction. A(aq) + B(aq) = C(aq) + D(aq) stronger acid stronger base weak acid weak base A. The position of the equilibrium shifts from left to right () B. The position of the equilibrium shifts from right to left () C. The position of the equilibrium doesn't move at all. D. The position of the equilibrium shifts randomly

A. The position of the equilibrium shifts from left to right ()

16. Which of the following is the correct expression for Kw of water? A. [H3O+][OH-] B. [H3O+][OH-]/[H2O]2 C. [H2O]/[ H3O+][OH-] D. [H3O+][OH-]/[H2O]

A. [H3O+][OH-] H2O(l) + H2O(l) H3O+(aq) + OH-(aq) Kw = [H3O+][OH-] [H2O][H2O] H2O is liquid so it doesn't count Therefore, Kw = [H3O+][OH-]

13. In which of the following radiation detectors is a gas ionized? A. a Geiger-Müller counter B. a scintillation counter C. all of the above D. none of the above

A. a Geiger-Müller counter

22. Which of the following buffers will have the best buffer capacity? A. a solution containing 0.1 M HC2H3O2 and 0.1 M NaC2H3O2 B. a solution containing 0.05 M HC2H3O2 and 0.15 M NaC2H3O2 C. a solution containing 0.15 M HC2H3O2 and 0.05 M NaC2H3O2 D. They all have the same buffer capacity.

A. a solution containing 0.1 M HC2H3O2 and 0.1 M NaC2H3O2 If a buffer contains the equal amount a weak acid and the salt of it conjugate base, it has the best buffer capacity.

21. Which of the following solutions can function as a buffer? A. a solution containing NH3 and NH4Cl B. a solution containing NaOH and NaCl C. a solution containing HCl and NaCl D. All of the above

A. a solution containing NH3 and NH4Cl Either weak acid with the salt of its conjugate base or a weak base with the salt of its conjugate acid can make a good buffer system. In B, NaOH is a strong base and in C, HCl is a strong acid so they won't function as a buffer.

1. Which of the following forms of radiation is the least penetrating? A. x B. b C. y D. positron

A. x

29. Which of the following has the WEAKEST penetrating power of radiation? A). x B). b C). y D). All of them have similar strength of penetration.

A. x

18. In an aqueous solution the [OH-] is 1.0 x 10- 2 M. What is the concentration of [H3O+] in this solution? A). 1 x 10-14 M B). 1 x 10-12 M C). 1 x 10- 11 M D). 1 x 10- 3 M

B). 1 x 10-12 M Kw = [H3O+][H3O+] = 10-14 [H3O+] = 10-14 = ----------- 10-2 M 10-12

12. When strong acids react with carbonates (CO32-) or bicarbonates (HCO3-), __ and ___ will be produced. A). CO2(g); H2(g); H2O(l) B). CO2(g); H2O(l) C). H2(g); H2O(l) D). H2O(l)

B). CO2(g); H2O(l)

4. Which of the following species can be characterized as amphiprotic? A). CO32- B). HCO3- C). H2CO3 D). All of the above

B). HCO3-

6. Which of the following is the conjugate base of H2CO3? A). H2CO3 B). HCO3- C). CO32- D). CO2

B). HCO3-

9. Which of the following can be characterized as a strong base? A). NH3 ammonia B). NaOH sodium hydroxide C). Al(OH)3 aluminum hydroxide D). Fe(OH)2 Iron (II) hydroxide

B). NaOH sodium hydroxide

30. What is the product from the alpha decay of Po-222 ? A). Pb-216 B). Pb-218 C). Po-216 D). At-218

B). Pb-218 222Po ? + 4He 2

13. Consider the following hypothetical acid-base reaction. A(aq) + B(aq) C(aq) + weak acid weak base strong acid D(aq) strong base A). The position of the equilibrium favors the forward reaction (shift to right). B). The position of the equilibrium favors the reverse reaction (shift to left). C). Neither the forward nor the reverse reaction are favored at equilibrium. D). The position of equilibrium cannot be predicted from the given data.

B). The position of the equilibrium favors the reverse reaction (shift to left).

19. An ammonia solution has a pH of 8.30, what is the [OH-] in this solution? A. 5.0 10-23 M B. 2.0 10- 6 M C. 5.0 10-9 M D. 2.0 108 M

B. 2.0 10- 6 M pH = 8.3 [H3O+] = 10-8.3 = 5.01 x 10-9 Kw = [H3O+][OH-]=10-14 [OH-] = 10-14/5.01 x 10-9 = 2 x 10-6 M

17. In an aqueous solution the [OH-] is 5.0 10-9 M. What is the [H3O+]? A. 1.0 10-7 M B. 2.0 10-6 M C. 1.0 10-8 M D. 5.0 x 10-9M

B. 2.0 10-6 M Kw = [H3O+][OH-]=10-14 [H3O+] = 10-14 = 2 x 10-6 M -------- 5 x 10-9

6. Polonium-210 is an emitter. What isotope is formed when 210Po emits an particle? A. 210At B. 206Pb C. 206Rn D. 206Xe

B. 206Pb 210Po ? + 4He 84 2 The atomic number 84 = ? + (2) ? = 82 (Pb) The mass number 210 = ? + (4) ? = 206

3. Which of the following can be characterized as a weak electrolyte? A. 0.001 M HCl B. 3.0 M CH3COOH C. Both A and B D. Neither A nor B

B. 3.0 M CH3COOH - HCl is a strong acid and completely dissociates into H+ and Cl- in aqueous solution. Therefore it is a strong electrolyte. - CH3COOH is a weak acid which only slightly dissociates in water so it is a weak electrolyte

15. If the intensity of radiation 1.0 m from a source is 300. mCi, what is the intensity 3.0 m from the source? A. 100. mCi B. 33 mCi C. 9.0 102 mCi D. 2.7 Ci

B. 33 mCi I1 = d22 300 mCi = 32 9 (?) = 300 mCi I2 d12 ? mCi 12 ? = 33 mCi

23. The pKa of acetic acid, HC2H3O2, is 4.75. What is the pH of a buffer in which [HC2H3O2] = 0.2 M and [NaC2H3O2] = 1.0 M ? A. 4.95 B. 5.45 C. 5.75 D. 7.00

B. 5.45 pH = pKa = log A- the cojugate base HA the acid pH = 4.75 + log 1 = 5.45 0.2

12. The half-life of I-131 is 8.00 days. If a medical treatment involves a dose of 400. mg of I-131, how much of the isotope remains after 48 days? A. 3.125 mg B. 6.25 mg C. 12.5 mg D. 25 mg

B. 6.25 mg 1 t ½ = 8 days 48 days x 1 half-life = 6 half-lives 8 days 400 mg x ½ x ½ x ½ x ½ x ½ x ½ = 6.25 mg

6. Which of the following is the conjugate acid of acetate ion, CH3COO- ? A. H3O+ B. CH3COOH C. CH3COO- D. OH-

B. CH3COOH The conjugate acid of a base, you add a H+ to the base.

3. Which of the following statements is true? A. In heavy atoms there are generally many more protons than neutrons. B. In heavy atoms there are generally many more neutrons than protons. C. In heavy atoms the number of protons and neutrons are nearly equal D. Most heavy atoms do not exist in a number of isotopic forms.

B. In heavy atoms there are generally many more neutrons than protons

2. According to Arrhenius which species is associated with all bases? A. H3O+ B. OH- C. H2O D. All of the above

B. OH-

14. In which of the following radiation detectors is a phosphor used? A. a Geiger-Müller counter B. a scintillation counter C. all of the above D. none of the above

B. a scintillation counter

20. The amount of radiation absorbed by tissues is measured by which of the following? A. curie B. rad C. roentgen D. All of the above

B. rad

If we mix equal molar amounts of a weak acid and a salt of its conjugate base, the pH of the solution will be equal to the pKa of the weak acid.

Buffer pH

32. The product from the positron emission of Cs-126 is ________. A). 126Cs 55 B). 123I 53 C). 127Xe 54 D). 127Ba 56

C). 127Xe 54 127Cs ? + oe +1

5. Which of the following is the conjugate acid of PO43-? A). H3PO4- B). H2PO4 C). HPO42- D). H3O+

C). HPO42-

36. When Bi-208 is bombarded with Ni-64, a new element with 6 neutrons are produced. what isotope of the new element is produced by this reaction? 208Bi +64Ni266?+61n 83 28 111 0 A). Ds-266 B). Ds-272 C). Rg-266 D). Rf-272

C). Rg-266

20. In a particular titration experiment a 30.0 mL sample of an unknown HCl solution required 25.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of HCl solution? A. 0.0833 M B. 0.120 M C. 0.167 M D. 0.240 M

C. 0.167 M HCl + NaOH NaCl + H2O 30 mL = 0.03 L 25 mL = 0.025 L ? M 0.2 M 0.2 M NaOH = 0.2 mol NaOH; you use 0.025 L NaOH soln. so 0.025 L x 0.2 mol NaOH 1 L 1 L Therefore, 0.005 mol NaOH is used to titrate equal mole of HCl, so HCl = 0.005 mole. Molarity of HCl = 0.005 mole/0.03 L = 0.167 M

16. The Ka for an acid is 1.8 x 10-4. What is the pKa of boric acid? A). - 9.14 B). - 4.86 C). 3.74 D). 9.14

C. 3.74

2. Which isotope of hydrogen is radioactive? A. 1H B. 2H C. 3H D. All of the above

C. 3H

15. The pKa of hydrocyanic acid is 9.31. What is the Ka of hydrocyanic acid? A. 1.3 10-24 B. 1.3 10-10 C. 4.9 10-10 D. 2.0 109

C. 4.9 10-10 Ka = 10-pKa = 10-9.3 = 4.9 x 10-10

5. Potassium-40 is a b emitter. What isotope is formed when 40K emits a b particle? A. 36Cl B. 40Ar C. 40Ca D. 44Ca

C. 40Ca 40K ? + 0e 19 -1 The atomic number 19 = ? + (-1) ? = 20 (Ca)

8. Cobalt-60 is a y emitter. What isotope is formed when 60Co emits y radiation? A. 60Mn B. 60Fe C. 60Co D. 60Ni

C. 60Co 60Co* ? + 27

27. What is the pH of a buffer prepared by mixing 100 mL of 0.50 M HEPES in its acid form with 200. mL of 0.50 M HEPES in its basic form? A). 6.55 B). 7.25 C). 7.85 D). 8.55

C. 7.85 pKa of HEPES = 7.55 pH = 7.55 + log 200 = 7.85 ---------- 100

11. Which of the following gases is produced when an acid reacts with an active metal? A). CO2 B). O2 C). H2 D). H2O

C. H2

7. Which of the following is the conjugate acid of PO43- A. H3PO4 B. H2PO4- C. HPO42- D. PO43-

C. HPO42- The conjugate acid of a base, you add a H+ back to the base.

4. Which of the following is the Brønsted-Lowry definition of an acid? A. a hydroxide ion acceptor B. a proton acceptor C. a proton donor D. All of the above

C. a proton donor

20. In an aqueous solution the [H3O+] is 1.0 x 10- 8M. What is the pH for this solution? A). pH = 14 B). pH = 12 C). pH = 8 D). pH = 6

C. pH= 8 pH=-log10-8 =-(-8) =8

23. In a particular titration experiment a 25.0 mL sample of HCl solution required 30.0 mL of 0.400 M NaOH for the end point to be reached. What is the concentration of pH + pOH =14 pOH = 14 - 7.4 = 6.6 the acid? A). 0.120 M B). 0.167 M C). 0.240 M D). 0.480 M

D). 0.480 M 30 mL = 0.03 L 25 mL = 0.025 L 0.4 M ? M 0.03 L x 0.4 mole NaOH = 0.012 mole NaOH = 0.012 ------------ 1L Molarity = 0.012 mole HCl = 0.48 M -------------- 0.025 L

25. The pKa of TRIS is 8.3. If you have the following TRIS buffers with various pH values. They will be active (useful) buffers EXCEPT A). A TRIS buffer at pH 7.35 B). A TRIS buffer at pH 7.95 C). A TRIS buffer at pH 8.30 D). A TRIS buffer at pH 6.90

D). A TRIS buffer at pH 6.90 PH = pKa 1 pH between 7.3 and 9.3 is effective

8. Which of the following can be characterized as a week acid? A). HI (hydroiodic acid) B). HCl (hydrochloric acid) C). H2SO4 (sulfuric acid) D). H2CO3 (carbonic acid)

D). H2CO3 (carbonic acid)

28. A nuclear equation is balanced when A). The same elements are found on both sides of the equation. B). The same particles and atoms are on both sides of the equation. C). Different particles and atoms are on both sides of the equation. D). The sum of the mass numbers and the sum of the atomic numbers of the particles and atoms are the same on both sides of the equation.

D). The sum of the mass numbers and the sum of the atomic numbers of the particles and atoms are the same on both sides of the equation.

17. Which of the following is the correct expression for Kw of water? H2O(l) + H2O(l) H3O+(aq) + OH-(aq) A). [H2O]/[ H3O+][OH-] B). [H3O+][OH-]/[H2O] C). [H3O+][OH-]/[H2O]2 D). [H3O+][OH-]

D). [H3O+][OH-]

34. Iron-59 has a half-life of 46 days. If the lab received a sample of 32 g iron-59. How many grams are still active after 230 days? A). 8 g B). 4 g C). 2g D). 1 g

D. 1 g 230 days x 1 half-life = 5 half-lives 46 days 32 g x 1 x 1 x 1 x 1 x 1 = 1 g 22222

14. The Ka for a substance is 1.2 10-11. What is the pKa of the substance? A. -10.92 B. -3.08 C. 3.08 D. 10.92

D. 10.92 pKa = - log 1.2 x 10-11 = - (-10.92) = 10.92

21. A solution has a pH of 7.4 What is its pOH? A). 10.6 B). 8.6 C). 7.4 D). 6.6

D. 6.6 pH ++ pOH =14 pOH = 14 - 7.4 = 6.6

18. A solution has a pOH of 6.6. What is its pH? A. - 6.6 B. - 7.4 C. 6.6 D. 7.4

D. 7.4 pH + pOH = 14 pH + 6.6 = 14 pH = 7.4

9. Beryllium-7 decays by electron capture. What isotope is formed when 7Be decays in this way? A. 7B B. 6Be C. 8Be D. 7Li

D. 7Li 7Be + 0e ? 4 +1 The atomic number 4 + (-1) = ? ? = 3 (Li)

24. What is the pH of a buffer solution prepared by mixing equal volumes of 0.15 M in TRIS in the acid form and 0.30 M in TRIS in the basic form? A. 6.55 B. 7.25 C. 8.00 D. 8.60

D. 8.60 The pKa of the TRIS acid form = 8.3 pH pH = 8.3 + log 0.30M pH = 8.3 + 0.3 0.1 M -------------- 0.15 M = 8.6

25. What are advantages for buffers that consist of Zwitterions such as HEPES? A. They are more resistant to temperature changes. B. They are more resistant to concentration changes. C. They do not readily permeate cell membrane. D. All of the above

D. All of the above

19. Which of the following is characteristic of the reaction shown in the image? A. nuclear fission B. chain reaction C. source of nuclear power generation D. All of these characterize the reaction.

D. All of these characterize the reaction.

5. Which of the following is a triprotic acid? A. HCl B. HNO3 C. H2SO4 D. H3PO4

D. H3PO4

18. Boron-10 is able to absorb neutrons and is therefore used in control rods in nuclear reactors. After B-10 absorbs a neutron it emits an particle. What isotope is produced as a result of neutron absorption followed by emission? A. B-11 B. Be-7 C. C-11 D. Li-7

D. Li-7 10B + 1n ? + 4He 5 0 2 The atomic number of ? = 5 + 0 = ? + 2 ? = 3 (Li) The mass number of ? : 10+ 1 = ? + 4 ? =7

8. What are the two acids in the following reaction? NH4+(aq) + HPO42-NH3 + H2PO4- A. NH4+ and HPO42- B. NH4+ and NH3 C. HPO42- and H2PO4- D. NH4+ and H2PO4-

D. NH4+ and H2PO4- First, you identify the reactants, which one is the acid and which one is the base. (The acid donates a H+ away; the base accepts a H+) Second, you identify two pairs that look very much alike but only have one H+ more/or less. They are an acid/base pair

11. What is the name of the acid which dissociates to give the nitrite ion, NO2-? A. hydronitric acid B. nitric acid C. nitride acid D. nitrous acid

D. nitrous acid HNO3 Nitric acid HNO2 Nitrous acid

9. Given the following information determine which of these acids is the WEAKEST? Ka for boric acid is 7.3 10-10 pKa = 9.14 pKa of acetic acid is 4.75 Ka for lactic acid is 8.4 10-4 pKa = 3.08 pKa of phenol is 9.89 A. acetic acid B. formic acid C. lactic acid D. phenol

D. phenol pKa = - log Ka The acidity increases, when pKa decreases The acidity increases , when Ka increases

The fragmentation of larger nuclei into smaller ones.

Nuclear Fission

The transmutation of two hydrogen nuclei into a helium nucleus liberates energy in the form of photons.

Nuclear Fusion

4. For 44Ca, there are _______. A. 20 protons and 20 neutrons. B. 44 protons and 44 neutrons. C. 24 protons and 20 neutrons. D. 20 protons and 24 neutrons

The atomic number of Ca = 20 20 protons , 20 elctrons The mass number of Ca = 44 = 20 protons + ? neutrons, ? neutrons = 44-20 = 24 D. 20 protons and 24 neutrons

Is a solution whose pH changes very little when small amounts of [H3O+] or [OH-] are added to it. "Shock absorber"

pH buffer

16. Which of the following gives the correct order of the penetrating power of radiation?

y>b>x