Ch
Ch
em 111
Lt
L
ec
t
ure
7
UMass Amherst Biochemistry Teaching Initiative
2
666
66
-
...
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Guidelines and tips
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community
Ask the community for help and clear up your study doubts
University Rankings
Discover the best universities in your country according to Docsity users
Free resources
Our save-the-student-ebooks!
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
Chemistry Lecture 7: Molar Mass, Empirical Formulas, and Chemical Equations, Lecture notes of Organic Chemistry
A portion of a university chemistry lecture from UMass Amherst, covering topics such as molar mass, empirical formulas, and chemical equations. Students are encouraged to continue reading Chapter 3, practice calculating percentages and molecular formulas, and learn about balanced chemical equations and stoichiometry.
What you will learn
- How do you balance a chemical equation?
- What is the molar mass of a compound?
- What is the difference between empirical and molecular formulas?
- What is stoichiometry and how is it used in chemistry?
- How do you calculate the percentage composition of a compound?
Typology: Lecture notes
2021/2022
Uploaded on 09/12/2022
unknown user 🇺🇸
1 / 16
This page cannot be seen from the preview
Don't miss anything!
Related documents
Partial preview of the text
Download Chemistry Lecture 7: Molar Mass, Empirical Formulas, and Chemical Equations and more Lecture notes Organic Chemistry in PDF only on Docsity!
ChCh
em 111^ L
t
L
ecture 7
UMass Amherst Biochemistry Teaching Initiative
2 6
6 6
6 6
-^
...
Homework• Continue Reading Chapter 3
OWL
li^
h^
k
- OWL online homework.
2 6
6 6
6 6
-^
...
Hydrates/ Solvated Crystals^ Often times when you get a compound the solvent will get trapped in thelattice.^ Blue = CoCl
2
Pink = CoCl
6H
O 2
2 6
6 6
6 6
-^
...
Let’s Practice^ Calculate the percentage of nitrogen (by mass) in Ca(NO
)^32
2 6
6 6
6 6
-^
...
Let’s Practice^ Anti-freeze, ethylene glycol, is composed of 38.7% carbon, 9.7% hydrogenand 51.6% oxygen by mass. Its molar mass is 62.1 g/mol. What is itsmolecular formula?molecular formula?
2 6
6 6
6 6
-^
...
Chemical Equations^ Concise way to represent chemical reactions.2 H (
g)
O (
g)^
Æ
2H O(
l)
2 H
( g) 2
O
( g) 2
Æ
2H
O( 2
l)
“+” = reacts with
reacts with Æ
= produces Left of arrow = reactantsRight of arrow = products
g^
p
Physical State(g)
= gas (l)
= liquid (s)
= solid ( aq)
= aqueous
2 6
6 6
6 6
-^
...
Combustion reactions^ Most reaction involve combining O
from air with a reactant. 2
When hydrocarbons are combusted they form CO
+ H 2
O. 2
Suppose we combust (or burn) methanol:CH
OH( 3
l )^
+^
O^2
( g
)^
Æ
CO
( g) 2
H
O( 2
l )
Balance Carbons:
1.^
Balance Carbons: CH
OH( 3
l )^
+^
O^2
( g
)^
Æ
CO
( g) 2
H
O( 2
l )
Balance Hydrogens:
2.^
Balance Hydrogens: CH
OH( 3
l )^
+^
O^2
( g
)^
Æ
CO
( g) 2
2H
O( 2
l )
- Balance Oxygens:
yg
CH
OH( 3
l )^
+ 3/2 O
g )
Æ
CO
( g) 2
2H
O( 2
l )
- Remove Fractional Coefficients 2 CH
OH( 3
l )^
+ 3O
g )^
Æ
2 CO
( g) 2
4 H
O( 2
l )
2 6
6 6
6 6
-^
...
Chemical EquilibriumChemical Equilibrium –
occurs when opposing reactions are proceeding at
the same rate.N O
Æ
2NO ( )
N^2
O^4
( g
)^
Æ
2NO
( g 2
2NO
g )
Æ
N
O 2
g )
2 6
6 6
6 6
-^
...
Aqueous SolutionsElectrolyte –
a substance whose aqueous solutions contains ions and
hence conduct electricity. N^
l^
t^
l t
b t
th t d
t f^
i^
i^
l ti
Non electrolyte -
a substance that does not form ions in solution.
2 6
6 6
6 6
-^
...
Ionic Compounds in Water^ Water is a polar solvent.^ NaCl(
s )^
Æ
Na
+^ (
aq
)^
+^
Cl
-^ (
aq
MgCl
( s 2
)^
Æ
Mg
2+^
( aq
)^
+^
2 Cl
-^ (
aq
MgSO
( s 4
)^ Æ
Mg
2+^
( aq
)^
+^
SO
2- 4
aq
2 6
6 6
6 6
-^
...
Solubility
Fig. 3-10, p. 126
2 6
6 6
6 6
-^
...