CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.
-
Upload
francis-rich -
Category
Documents
-
view
229 -
download
3
Transcript of CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.
![Page 1: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/1.jpg)
CHAPTER 4
4.3 Chemical Reactions in the Lab
Physical and Chemical
Change
![Page 2: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/2.jpg)
2 4.3 Chemical Reactions in the Lab
Why would the presence of water on Mars be a sign that life might exist there?
![Page 3: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/3.jpg)
3 4.3 Chemical Reactions in the Lab
Many reactions, including those that sustain life, involve chemicals dissolved in water.
Why would the presence of water on Mars be a sign that life might exist there?
![Page 4: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/4.jpg)
4 4.3 Chemical Reactions in the Lab
DRY
Light blue powder
No reaction
![Page 5: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/5.jpg)
5 4.3 Chemical Reactions in the Lab
DRY
No reaction
IN SOLUTION
Light blue powder NaS(aq) CuSO4(aq)
Chemical reaction
A precipitate is an insoluble compound.
![Page 6: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/6.jpg)
6 4.3 Chemical Reactions in the Lab
A solution with water as the solvent is called an aqueous solution.
“Aqua” means “water.”
SYMBOLS
(s) indicates a solid
(l) indicates a liquid
(g) indicates a gas
(aq) indicates a substance dissolved in water (an aqueous solution)
![Page 7: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/7.jpg)
7 4.3 Chemical Reactions in the Lab
S O
O
O
OCu
Cu
S O
O
O
O
2–
2+
OH
H
OH
H
OH
HO
H H
A salt is an ionic compound that forms ions when dissolved in water.
![Page 8: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/8.jpg)
8 4.3 Chemical Reactions in the Lab
Can you translate what you see into a chemical equation?
![Page 9: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/9.jpg)
9 4.3 Chemical Reactions in the Lab
Can you translate what you see into a chemical equation?
Zn(s) + CuSO4(aq)Cu(s)
and Zn(s) is disappearing
![Page 10: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/10.jpg)
10 4.3 Chemical Reactions in the Lab
Zn(s) + CuSO4(aq)Cu(s)
and Zn(s) is disappearing
Can you translate what you see into a chemical equation?
a salt in water!
![Page 11: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/11.jpg)
11 4.3 Chemical Reactions in the Lab
Cu2+(aq)
SO42–(aq)
Can you translate what you see into a chemical equation?
Zn(s) +Cu(s)
and Zn(s) is disappearing
![Page 12: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/12.jpg)
12 4.3 Chemical Reactions in the Lab
Cu2+(aq)
SO42-(aq)
Zn(s) +Cu(s)
and Zn(s) is disappearing
The copper ion gains 2 electrons to form solid copper.
reduction: a chemical reaction that decreases the charge of an atom or ion by accepting electrons.
Cu2+(aq) + 2e– Cu(s)
![Page 13: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/13.jpg)
13 4.3 Chemical Reactions in the Lab
Cu2+(aq)
SO42-(aq)
Zn(s) +Cu(s)
and Zn(s) is disappearing
The copper ion gains 2 electrons to form solid copper.
Where could those electrons
come from?
Cu2+(aq) + 2e– Cu(s)
![Page 14: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/14.jpg)
14 4.3 Chemical Reactions in the Lab
Cu2+(aq)
SO42-(aq)
Zn(s) +Cu(s)
and Zn(s) is disappearing
Zn(s) Zn2+(aq) + 2e–
Zinc gives up 2 electrons to become a zinc ion, dissolved in water.
Cu2+(aq) + 2e– Cu(s)
![Page 15: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/15.jpg)
15 4.3 Chemical Reactions in the Lab
Zn(s) Zn2+(aq) + 2e–
Zinc gives up 2 electrons to become a zinc ion, dissolved in water.
oxidation: a chemical reaction that increases the charge of an atom or ion by giving up electrons.
![Page 16: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/16.jpg)
16 4.3 Chemical Reactions in the Lab
Cu2+(aq) + 2e– Cu(s)
Reactants Products
reduction
REACTION NAME
![Page 17: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/17.jpg)
17 4.3 Chemical Reactions in the Lab
Cu2+(aq) + 2e– Cu(s)
Zn(s) Zn2+(aq) + 2e–
Reactants Products
reduction
REACTION NAME
oxidation
![Page 18: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/18.jpg)
18 4.3 Chemical Reactions in the Lab
Cu2+(aq) + 2e– Cu(s)
Zn(s) Zn2+(aq) + 2e–
Reactants Products
reduction
REACTION NAME
oxidation
These 2 reactions are happening at the same time.
To obtain the overall reactionadd the reactants, then the products.
![Page 19: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/19.jpg)
19 4.3 Chemical Reactions in the Lab
Cu2+(aq) + 2e– Cu(s)
Zn(s) Zn2+(aq) + 2e–
Reactants Products
Cu2+(aq) + Zn(s) Cu(s) + Zn2+(aq)
reduction
REACTION NAME
oxidation
redox
![Page 20: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/20.jpg)
20 4.3 Chemical Reactions in the Lab
O
H HO
H
H- +
dissociation
H2O OH– + H+
The double arrow indicates that the reaction goes in both ways.
The heavier arrow means that the reverse reaction is favored.
![Page 21: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/21.jpg)
21 4.3 Chemical Reactions in the Lab
Classify these items as acids or bases.
![Page 22: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/22.jpg)
22 4.3 Chemical Reactions in the Lab
HCl(l) H+(aq) + Cl–(aq)H2O(l)
acid: a chemical that dissolves in water to create more H+ ions than there are in neutral water.
Acids give foods like lemons their sour taste.Acids react with metal to create hydrogen gas (H2).Acids can corrode metal and burn skin.
Example:
Hydrochloric acid
![Page 23: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/23.jpg)
23 4.3 Chemical Reactions in the Lab
NaOH(l) Na+(aq) + OH–(aq)H2O(l)
Bases create a bitter taste.Bases have a slippery feel, like soap.Bases can neutralize acids.
Example:
Sodium hydroxide
![Page 24: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/24.jpg)
24 4.3 Chemical Reactions in the Lab
NaOH(l) Na+(aq) + OH–(aq)H2O(l)
Bases create a bitter taste.Bases have a slippery feel, like soap.Bases can neutralize acids.
Example:
Sodium hydroxide
OH–(aq) + H+(aq) H2O(l)
Result: fewer H+ ions
![Page 25: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/25.jpg)
25 4.3 Chemical Reactions in the Lab
NaOH(l) Na+(aq) + OH–(aq)H2O(l)
Example:
Sodium hydroxide
OH–(aq) + H+(aq) H2O(l)
Result: fewer H+ ions
base: a chemical that dissolves in water to create fewer H+ ions (or more OH– ions)than there are in neutral water.
![Page 26: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/26.jpg)
26 4.3 Chemical Reactions in the Lab
![Page 27: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/27.jpg)
27 4.3 Chemical Reactions in the Lab
Higher H+ concentration Lower H+ concentration
The pH scale helps to determine whether a solution is acidic or basic.
![Page 28: CHAPTER 4 4.3 Chemical Reactions in the Lab Physical and Chemical Change.](https://reader036.fdocuments.in/reader036/viewer/2022062408/56649f2c5503460f94c470a4/html5/thumbnails/28.jpg)
28 4.3 Chemical Reactions in the Lab
A solution with water as the solvent is called an aqueous solution.
Redox reactions
(transfer of electrons)
Acid-base reactions
(transfer of protons, H+ ions)
two types of chemical reactions that take place in an aqueous environment.
Higher H+ concentration Lower H+ concentration