announcements
DESCRIPTION
Announcements. REMINDER: NO LAB THIS WEEK EXAM CLARIFICATION/FRIDAY DEADLINE SET CLICKER TO CHANNEL 41. Bases. Strong bases are hydroxide salts For now, only important weak base is NH 3 Ionization of weak acid produces a weak base. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/1.jpg)
•REMINDER: NO LAB THIS WEEK
•EXAM CLARIFICATION/FRIDAY DEADLINE
•SET CLICKER TO CHANNEL 41
Announcements
![Page 2: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/2.jpg)
Bases
Strong bases are hydroxide salts
For now, only important weak base is NH3
Ionization of weak acid produces a weak base
![Page 3: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/3.jpg)
If the oxalate anion (C2O4-) reacts in an acid-base reaction,
which of the following can’t it make?
1 2 3
28%
53%
19%
1. H2C2O4
2. HC2O4-
3. 2CO2
![Page 4: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/4.jpg)
Acid Base Reactions
![Page 5: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/5.jpg)
Acid Base Reactions
Strong Acid + Strong Base
HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) acid base “salt” water
What do we get if we mix:
HBr (aq) + LiOH (aq)
![Page 6: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/6.jpg)
Acid Base Reactions
Diprotic acids or bases
H2SO4(aq) + NaOH(aq)
H2SO4(aq) + Ba(OH)2(aq)
HCl(aq) + Ba(OH)2(aq)
![Page 7: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/7.jpg)
Acid Base Reactions
Strong Acid + Weak Base
HCl(aq) + NH3(aq)
What do we get if we mix:
HNO3(aq) + NH3(aq)
![Page 8: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/8.jpg)
Acid Base Reactions
Weak Acid + Strong Base (like strong acid+strong base)
HCN(aq) + NaOH(aq) NaCN(aq) + H2O(l) acid base “salt” water
What do we get if we mix:
HCOOH (aq) + KOH (aq) formic acid
![Page 9: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/9.jpg)
Net Ionic Equations
1. Write a balanced chemical equation Molecular equation
1. Write out all the ions Total ionic equation
2. Cancel out anything that appears on both sides
Net ionic equation
![Page 10: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/10.jpg)
Net Ionic Equations
HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)
What really happens:
H+(aq) + OH-(aq) H2O(l)
Sodium ion and chloride ion are “spectator ions”
![Page 11: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/11.jpg)
Reactions Involving a Weak Base
Molecular equation:
HCl(aq) + NH3(aq) NH4Cl(aq)
Total ionic equation:
H+(aq) + Cl-(aq) + NH3(aq) NH4+
+ Cl-(aq)
Net ionic equation:
H+(aq) + NH3(aq) NH4+ (aq)
What is the net ionic equation for:
HNO3(aq) + NH3(aq) NH4NO3(aq)
![Page 12: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/12.jpg)
CH3CO2H(aq) + NaOH(aq)
1 2 3
33% 33%33%1. CH3CO2H2
+(aq) + NaO(aq)
2. CH3CO2-(aq) + H2O(l) + Na+(aq)
3. CH4(g) + CO2(g) + H2O(l)
20
![Page 13: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/13.jpg)
HCN(aq) + NH3(aq)
1 2 3
33% 33%33%
20
1. NH4+(aq) + CN-(aq)
2. H2CN+(aq) + NH2-(aq)
3. C2N2(s) + 3 H2(g)
![Page 14: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/14.jpg)
The pH Scale
Quantitative measure of solution acidity
Remember solution concentration:
[NaCl]=0.25M means 0.25 moles of NaCl are in 1L of solution
solventL
solutemolesMolarity
1
#
![Page 15: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/15.jpg)
The pH Scale
In pure water, some molecules ionize to form H3O+ and OH-
H2O + H2O OH– + H3O+
In acidic and basic solutions, these concentrations are not equal
acidic: [H3O+] > [OH–]
basic: [OH–] > [H3O+]
neutral: [H3O+] = [OH–]
![Page 16: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/16.jpg)
The pH Scale
pH scale= measure of [H3O+]pH < 7.0 = acidicpH > 7.0 = basicpH = 7.0 = neutral
Measure of H3O+ concentration (moles per liter) in a solution
As acidity increases, pH decreases
![Page 17: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/17.jpg)
The pH Scale
The pH scale is logarithmic100100 101022 log(10log(1022) = 2) = 21010 101011 log(10log(1011) = 1) = 111 101000 log(10log(1000) = 0) = 00.10.1 1010–1–1 log(10log(10–1–1) = –1) = –10.010.01 1010–2–2 log(10log(10–2–2) = –2) = –2
pH = –log [HpH = –log [H33OO++]]
pH if [HpH if [H33OO++] = 10] = 10–5–5? 10? 10–9–9??
Acidic or basic?Acidic or basic?
pH if [HpH if [H33OO++] = 0.000057 M?] = 0.000057 M?
![Page 18: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/18.jpg)
Finding [H3O+] from pH
[H[H33OO++] = 10] = 10-pH-pH or [H or [H33OO++] = log] = log-1-1 (-pH) (-pH)
Finding the inverse log (or log Finding the inverse log (or log -1-1)of a number )of a number on your calculator:on your calculator:
Enter the number, press the inverse (inv) or shift button, Enter the number, press the inverse (inv) or shift button, the press the log button (it might be labeled 10the press the log button (it might be labeled 10xx))
What is [HWhat is [H33OO++] if pH = 8.6?] if pH = 8.6?
![Page 19: Announcements](https://reader035.vdocument.in/reader035/viewer/2022070405/56813d3a550346895da6f930/html5/thumbnails/19.jpg)
pH: Quantitative Measure of Acidity
Acidity is related to concentration of H+ (or H3O+)
pH = -log[H3O+]
[H3O+]=10-pH=log-1(-pH)