1 22 What Are Strong Acids And Bases

1. Launch: 1/22
 Grab your binder and immediately take a seat!
 Place launch paper and practice questions (Tuesday
1/19) on your desk.
 Tuesday’s Exit Slip Data:
 Today’s Objective: I can define a Brønsted-Lowry acid and
base.
96%

2. Launch 1/21
1. Which of the following is true about acids?
a. they taste bitter
b. they turn litmus paper blue
c. they have a pH of greater than 7
d. they taste sour and turn litmus paper red

3. Launch 1/21
2. Baking soda is an example of an
a. acid because it turns litmus paper red
b. base because it has a pH of about 8.5
c. acid because it turns litmus paper blue
d. base because it tastes similar to lemons

4. Launch 1/21
3. Which of the following solutions would have the
highest acidity?
a. pH 11
b. pH 9
c. pH 5
d. pH 2

5. Launch 1/21
4. Which of the following explains why Kool-aid
powder dissolves in water?
a. The Kool-aid powder is cold and therefore has a high
solubility.
b. The random motion of the solvent molecules causes
collisions with the solute molecules and dissolving
occurs.
c. The solute has strong intermolecular attractions and
is therefore easily dissolved.
d. The concentration of the solute is higher than the
concentration of the solvent and dissolving occurs.

6. Announcements
 Missing work is due today
 Check board for your name
 Quiz tomorrow!
 Short quiz – 15 MC
 Lab questions due tomorrow!
 Unit #6 exam moved to Thursday 1/28

7. January Calendar

8. What are strong
acids/bases?
Mr. Heffner
1/22/10

9. What are strong acids/bases?
 Strong acids/bases…
 fully dissociate in solution
“break up”
HCl  H
+
+ Cl
–
Hydrogen
ion
Chloride
ion
NaOH  Na
+
+ OH
–
Sodium
ion
Hydroxide
ion
HCl
H
+

H
+

H
+
H
+

H
+

H
+

H
+

Cl
-

Cl
-

Cl
-

Cl
-

Cl
-

Cl
-

NaOH
Na
+

Na
+

Na
+
Na
+

Na
+

Na
+

Na
+

OH
-

OH
-

OH
-

OH
-

OH
-

OH
-

all
broken
up

10. What are weak acids/bases?
 Weak acids/bases…
 only partially dissociate in solution
“break up”
HF  H
+
+ F
–
HF
HF
H
+

HF HF
H
+

H
+

HF
F
-

F
-

F
-

F
-

F
-

F
-

partially
broken
up

11. Summary
Hydrogen
ion
HCl
H
+

H
+

H
+
H
+

H
+

H
+

H
+

Cl
-

Cl
-

Cl
-

Cl
-

Cl
-

Cl
-

HCl  H
+
+ Cl
–
Strong acids/bases
 fully dissociate
Weak acids/bases
 partially dissociate
HF  H
+
+ F
–
HF
HF
H
+

HF HF
H
+

H
+

HF
F
-

F
-

F
-

F
-

F
-

F
-

Video Summary

12. What are strong acids/bases?
 What happens if you mix a strong acid and a strong
base?
 strong acid + strong base = water + salt
 Neutralization
HCl + NaOH  ?

H
+
+ Cl
-
Na
+
+ OH
-
+

?

H
2
O

+

NaCl

water salt

13. Practice Questions
 Practice question worksheet

14. Exit Slip
1. Which of the following are properties of acids?
a. they taste bitter and turn litmus paper blue
b. they have a pH of less than 7 and turn litmus paper red
c. they have a pH of greater than 7 and taste sour
d. they usually feel slippery like soap

15. Exit Slip
2. The Bronsted-Lowry definition of a base is
a. a molecule that loses an electron
b. a molecule that has a pH of greater than 7
c. a molecule that donates hydrogen ions
d. a molecule that accepts hydrogen ions

16. Exit Slip
3. In the equation, H
2
O + HI  H
3
O
+
+ I
-
, which
reactant molecule acts as the acid?
a. H
2
O
b. HI
c. H
3
O
+

d. I
-

17. Exit Slip
4. In the equation, H
2
PO
4
-
+ H
2
O  H
3
PO
4
+ OH
-
,
which reactant molecule acts as the base?
a. H
3
PO
4

b. OH
-

c. H
2
PO
4
-

d. H
2
O

18. Exit Slip
5. Why could SO
4
2-
not act as a Bronsted-Lowry acid?
a. because it can donate O
2-
ions to solution
b. because it has no H
+
ions to donate to solution
c. because it cannot accept any H
+
ions
d. because it has a pH of 6

19. Homework
 Finish practice questions