Download - "for studies of G-protein-coupled receptors"
"for studies of G-protein-coupled receptors"
萊夫科維茲（ Robert Lefkowitz ）和克比爾卡（ Brian Kobilka ）因發現 G 蛋白耦合性受體的內部運作方式而獲獎，他們兩人研究讓身體細胞對外界訊號有所反應的蛋白質，對 G 蛋白耦合性受體有突破性的發現。
G 蛋白耦合性受體為重要的受體家族，大約一半的藥物都作用於這些受體，因此對這些受體的認識將有助科學家研發效果更好的藥物。
As yet, how many Nobel Prize in Chemistry
You know?
Additional HW: (one page A4 )
由學號選擇年份 : 如 1 號 選擇 2011; 2 號選擇 2010…
Reactions in Aqueous Solution
Chapter 4
Why we talk about “solution”
• Most of chemical reaction and bio-processing occurs in “solution” phase
3
DNA in buffer solutionLi-ion battery
4
A solution is a homogenous mixture of 2 or more substancesThe solute is(are) the substance(s) present in the smaller amount(s)
The solvent is the substance present in the larger amount
Solution Solvent Solute
Soft drink(l)
Air(g)
Soft Solder(s)
H2O
N2
Pb
Sugar, CO2
O2, Ar, CH4
Snaqueous solutions
of KMnO4
焊錫
Definition of Solution
5
An electrolyte is a substance that, when dissolved in water, results in a solution that can conduct electricity.
A nonelectrolyte is a substance that, when dissolved, results in a solution that does not conduct electricity.
nonelectrolyte weak electrolyte strong electrolyte
Electrolyte
6
Strong Electrolyte – 100% dissociation
NaCl(s) Na+(aq) + Cl-(aq)H2O
Weak Electrolyte – not completely dissociated
CH3COOH CH3COO-(aq) + H+(aq)
Conduct electricity in solution?
Cations (+) and Anions (-)
The degree of dissociation
7
Ionization of acetic acid
CH3COOH CH3COO-(aq) + H+(aq)
A reversible reaction. The reaction can occur in both directions.(Until it reach the chemical equilibrium)
Acetic acid is a weak electrolyte because its ionization in water is incomplete.
醋酸
8
Nonelectrolyte does not conduct electricity?
No cations (+) and anions (-) in solution
C6H12O6(s) C6H12O6(aq)H2O
9
Electrolyte in Electrochemical Reaction: applications
1. Solar cell (Dye-sensitized solar cell)2. Electroplating 3. Battery(Li-ion battery etc)4. Chemical sensor or biomedical sensor5. Etching …… and so on
10
Graphene Ink Electrochemical Exfoliation of graphite to produce thin graphene
films
Vedio clip
C.Y. Su et al., ACS Nano (2011)
11
Hydration is the process in which an ion is surrounded by water molecules arranged in a specific manner.
H2O
Hydration(水合 )
水分子為一種良好的極性溶劑
12
Precipitation Reactions
Precipitate – insoluble solid that separates from solution
molecular equation
ionic equation
net ionic equation
Pb2+ + 2NO3- + 2Na+ + 2I- PbI2(s) + 2Na+ + 2NO3
-
Na+ and NO3- are spectator ions
PbI2
Pb(NO3)2(aq) + 2NaI(aq) PbI2(s) + 2NaNO3(aq)
precipitate
Pb2+ + 2I- PbI2(s)
旁觀離子
13
Precipitation of Lead Iodide
PbI2Pb2+ + 2I- PbI2(s)
14
Solubility is the maximum amount of solute that will dissolve in a given quantity of solvent at a specific temperature.
AgCl
15
Examples of Insoluble Compounds
CdS PbS Ni(OH)2 Al(OH)3
16
Writing Net Ionic Equations1. Write the balanced molecular equation.
2. Write the ionic equation showing the strong electrolytes completely dissociated into cations and anions.
3. Cancel the spectator ions on both sides of the ionic equation
4. Check that charges and number of atoms are balanced in the net ionic equation
AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
Ag+ + NO3- + Na+ + Cl- AgCl(s) + Na+ + NO3
-
Ag+ + Cl- AgCl(s)
Write the net ionic equation for the reaction of silver nitrate with sodium chloride.
17
Properties of Acids
Have a sour taste. Vinegar owes its taste to acetic acid. Citrusfruits contain citric acid.
React with certain metals to produce hydrogen gas.
React with carbonates and bicarbonatesto produce carbon dioxide gas
Cause color changes in plant dyes.
2HCl(aq) + Mg(s) MgCl2(aq) + H2(g)
2HCl(aq) + CaCO3(s) CaCl2(aq) + CO2(g) + H2O(l)
Aqueous acid solutions conduct electricity.
( 醋 )
18
Have a bitter taste.
Feel slippery. Many soaps contain bases.
Properties of Bases
Cause color changes in plant dyes.
Aqueous base solutions conduct electricity.
Examples:
Ex: NaOH
19
Arrhenius acid is a substance that produces H+ (H3O+) in water
Arrhenius base is a substance that produces OH- in water
Arrhenius theory:
20
A Brønsted acid is a proton donorA Brønsted base is a proton acceptor
acidbase acid base
A Brønsted acid must contain at least one ionizable proton!
Brønsted theory:
Donate proton
21
Hydronium ion, hydrated proton, H3O+
水合質子
H2O
22
Example: 鎖相萃取法
以蒸餾的純水帶走產物中的離子
23
Monoprotic acids
HCl H+ + Cl-
HNO3 H+ + NO3-
CH3COOH H+ + CH3COO-
Strong electrolyte, strong acid
Strong electrolyte, strong acid
Weak electrolyte, weak acid
Diprotic acidsH2SO4 H+ + HSO4
-
HSO4- H+ + SO4
2-
Strong electrolyte, strong acid
Weak electrolyte, weak acid
Triprotic acidsH3PO4 H+ + H2PO4
-
H2PO4- H+ + HPO4
2-
HPO42- H+ + PO4
3-
Weak electrolyte, weak acid
Weak electrolyte, weak acid
Weak electrolyte, weak acid
Strong and Weak acid 單質子酸
雙質子酸
三質子酸
24
Identify each of the following species as a Brønsted acid, base, or both. (a) HI, (b) CH3COO-, (c) H2PO4
-
HI (aq) H+ (aq) + I- (aq) Brønsted acid
CH3COO- (aq) + H+ (aq) CH3COOH (aq) Brønsted base
H2PO4- (aq) H+ (aq) + HPO4
2- (aq)
H2PO4- (aq) + H+ (aq) H3PO4 (aq)
Brønsted acid
Brønsted base
Example:
25
Neutralization Reaction ( 中和反應 )
acid + base salt + water
HCl(aq) + NaOH(aq) NaCl(aq) + H2O
H+ + Cl- + Na+ + OH- Na+ + Cl- + H2O
H+ + OH- H2O
26
Neutralization Reaction Involving a Weak Electrolyte
weak acid + base salt + water
HCN(aq) + NaOH(aq) NaCN(aq) + H2O
HCN + Na+ + OH- Na+ + CN- + H2O
HCN + OH- CN- + H2O
27
Neutralization Reaction Producing a Gas
acid + base salt + water + CO2
2HCl(aq) + Na2CO3(aq) 2NaCl(aq) + H2O +CO2
2H+ + 2Cl- + 2Na+ + CO32- 2Na+ + 2Cl- + H2O + CO2
2H+ + CO32- H2O + CO2
28
Oxidation-Reduction Reactions( 氧化還原反應 )
(electron transfer reactions)
2Mg 2Mg2+ + 4e-
O2 + 4e- 2O2-
Oxidation half-reaction (lose e-)
Reduction half-reaction (gain e-)
2Mg + O2 + 4e- 2Mg2+ + 2O2- + 4e-
2Mg + O2 2MgO
29
30
Zn(s) + CuSO4(aq) ZnSO4(aq) + Cu(s)
Zn is oxidizedZn Zn2+ + 2e-
Cu2+ is reducedCu2+ + 2e- Cu
Zn is the reducing agent
Cu2+ is the oxidizing agent
Copper wire reacts with silver nitrate to form silver metal.What is the oxidizing agent in the reaction?
Cu(s) + 2AgNO3(aq) Cu(NO3)2(aq) + 2Ag(s)
Cu Cu2+ + 2e-
Ag+ + 1e- Ag Ag+ is reduced Ag+ is the oxidizing agent
Electron transfer reactions
Oxidation number( 氧化數 )
The charge the atom would have in a molecule (or anionic compound) if electrons were completely transferred.
4.4
分子化合物的生成過程，沒有電子轉移，因此定義氧化數的概念來說明氧化還原態
EX: H2(g)+Cl2(g)2HCl(g) S(s)+ O2(g)SO2(g)
0
0
0
0
+1 -1
+4 -2
氧化數減少，該元素即被還原 (Cl 及 O)
氧化數增加，該元素即被氧化 (H 及 S)
Determine the oxidation number( 如何決定氧化數 )
32
32
1. Free elements (uncombined state) have an oxidation number of zero.
Na, Be, K, Pb, H2, O2, P4 = 0
2. In monatomic ions, the oxidation number is equal to the charge on the ion.
Li+, Li = +1; Fe3+, Fe = +3; O2-, O = -2
3. The oxidation number of oxygen is usually –2. In H2O2
and O22- it is –1.
元素態
單原子離子
33
4. The oxidation number of hydrogen is +1 except when it is bonded to metals in binary compounds. In these cases, its oxidation number is –1.( 如 LiH, NaH, CaH2)
6. The sum of the oxidation numbers of all the atoms in a molecule or ion is equal to the charge on the molecule or ion.( 如 NH4
+)
5. Group IA metals are +1, IIA metals are +2 and fluorine is always –1.
HCO3-
O = –2 H = +1
3x(–2) + 1 + ? = –1
C = +4
What are the oxidation numbers of all the elements in HCO3
- ?
7. Oxidation numbers do not have to be integers. Oxidation number of oxygen in the superoxide ion, O2
-, is –½.
34
The Oxidation Numbers of Elements in their Compounds
1. 金屬離子氧化數皆正數，非金屬離子則有正有負2. 紅色表示常見的氧化數
35
NaIO3
Na = +1 O = -2
3x(-2) + 1 + ? = 0
I = +5
IF7
F = -1
7x(-1) + ? = 0
I = +7
K2Cr2O7
O = -2 K = +1
7x(-2) + 2x(+1) + 2x(?) = 0
Cr = +6
What are the oxidation numbers of all the elements in each of these compounds? NaIO3 IF7 K2Cr2O7
Example:
36
Types of Oxidation-Reduction Reactions
Combination Reaction
A + B C
3Mg + N2 MgN2
Decomposition Reaction
2KClO3 2KCl + 3O2
C A + B
0 0 +2 -3
+1 +5 -2 +1 -1 0
( 結合反應 )
( 分解反應 )
1Al+Br22AlBr3
37
Types of Oxidation-Reduction Reactions
Combustion Reaction( 燃燒 )
A + O2 B
S + O2 SO2
0 0 +4 -2
2Mg + O2 2MgO0 0 +2 -2
38
Displacement Reaction( 取代反應 )
A + BC AC + B
Sr + 2H2O Sr(OH)2 + H2
TiCl4 + 2Mg Ti + 2MgCl2
Cl2 + 2KBr 2KCl + Br2
Hydrogen Displacement
Metal Displacement
Halogen Displacement
Types of Oxidation-Reduction Reactions
0 +1 +2 0
0+4 0 +2
0 -1 -1 0
鹵素
39
The Activity Series for Metals
M + BC MC + B
Hydrogen Displacement Reaction
M is metalBC is acid or H2O
B is H2
Ca + 2H2O Ca(OH)2 + H2
Pb + 2H2O Pb(OH)2 + H2
40
The Activity Series for Halogens
Halogen Displacement Reaction
Cl2 + 2KBr 2KCl + Br2
0 -1 -1 0
F2 > Cl2 > Br2 > I2
I2 + 2KBr 2KI + Br2
41
Ca2+ + CO32- CaCO3
NH3 + H+ NH4+
Zn + 2HCl ZnCl2 + H2
Ca + F2 CaF2
Precipitation
Acid-Base
Redox (H2 Displacement)
Redox (Combination)
Classify each of the following reactions.
Examples:
42
Solution Stoichiometry( 溶液的化學計量 )
The concentration of a solution is the amount of solute present in a given quantity of solvent or solution.
M = molarity =moles of solute
liters of solution
What mass of KI is required to make 500. mL of a 2.80 M KI solution?
volume of KI solution moles KI grams KIM KI M KI
500. mL = 232 g KI166 g KI
1 mol KIx
2.80 mol KI
1 L solnx
1 L
1000 mLx
莫耳濃度或體積莫耳濃度
43
Preparing a Solution of Known Concentration
44
Dilution is the procedure for preparing a less concentrated solution from a more concentrated solution.
DilutionAdd Solvent
Moles of solutebefore dilution (i)
Moles of soluteafter dilution (f)=
MiVi MfVf=
稀釋
45
How would you prepare 60.0 mL of 0.200 M HNO3 from a stock solution of 4.00 M HNO3?
MiVi = MfVf
Mi = 4.00 M Mf = 0.200 M Vf = 0.0600 L Vi = ? L
Vi =MfVf
Mi
= 0.200 M x 0.0600 L4.00 M
= 0.00300 L = 3.00 mL
Dilute 3.00 mL of acid with water to a total volume of 60.0 mL.
46
Gravimetric Analysis( 重量分析 )1. Dissolve unknown substance in water
2. React unknown with known substance to form a precipitate
3. Filter and dry precipitate
4. Weigh precipitate
5. Use chemical formula and mass of precipitate to determine amount of unknown ion
47
Titrations( 滴定分析 )In a titration a solution of accurately known concentration is added gradually added to another solution of unknown concentration until the chemical reaction between the two solutions is complete.
Equivalence point – the point at which the reaction is complete
Indicator – substance that changes color at (or near) the equivalence point
Slowly add baseto unknown acid
UNTIL
the indicatorchanges color
當量點 : 酸鹼完全中和反應的 點
指示劑
48
Titrations can be used in the analysis of
Acid-base reactions
Redox reactions
H2SO4 + 2NaOH 2H2O + Na2SO4
5Fe2+ + MnO4- + 8H+ Mn2+ + 5Fe3+ + 4H2O
酸鹼滴定
氧化還原滴定
當達到當量點 , H 離子總莫耳數等於 OH 離子的總莫耳數
使用氧化還原指示劑來觀察當量點的發生
49
What volume of a 1.420 M NaOH solution is required to titrate 25.00 mL of a 4.50 M H2SO4 solution?
WRITE THE CHEMICAL EQUATION!
volume acid moles red moles base volume base
H2SO4 + 2NaOH 2H2O + Na2SO4
4.50 mol H2SO4
1000 mL solnx
2 mol NaOH
1 mol H2SO4
x1000 ml soln
1.420 mol NaOHx25.00 mL = 158 mL
M
acid
rxn
coef.
M
base
Examples
50
WRITE THE CHEMICAL EQUATION!
volume red moles red moles oxid M oxid
0.1327 mol KMnO4
1 Lx
5 mol Fe2+
1 mol KMnO4
x1
0.02500 L Fe2+x0.01642 L = 0.4358 M
M
red
rxn
coef.
V
oxid
5Fe2+ + MnO4- + 8H+ Mn2+ + 5Fe3+ + 4H2O
16.42 mL of 0.1327 M KMnO4 solution is needed to oxidize 25.00 mL of an acidic FeSO4 solution. What is the molarity of the iron solution?
16.42 mL = 0.01642 L 25.00 mL = 0.02500 L
51
1. Give the oxidation number of the underlined atoms in the following molecules and ions: (a) ClF, (b) IF7, (c) CH4, (d) C2H2, (e) C2H4, (f) K2CrO4, (g) K2Cr2O7, (h) KMnO4
2. Describe how to prepare 1.00 L of 0.646 M HCl solution, starting with a 2.00 M HCl solution.
3. Calculate the concentration (in molarity) of a NaOH solution if 25.0 mL of the solution are needed to neutralize 17.4 mL of a 0.312 M HCl solution.
HW ch4
