Chapter 1: Measurements in
Chemistry
! Mass
! Volume
! Temperature
! Amount
Chapter 1: Measurements in
Chemistry
! Mass
1 kg (SI standard, 2.2 lb)
1 g (1 gram)
1 mg (1 milligram)
1 kg = 1000 g
1 g = 1000 mg
Chapter 1: Measurements in
Chemistry
! Volume
1 m3 (SI standard)
1 L (1 liter) = 1 dm3
1 mL = 1 cm3
1 m3 = 1000 L
1 L = 1000 mL
Chapter 1: Measurements in
Chemistry
! Volume
1 m3
1L
1 dm3
1000 L
1,000,000 mL
1000 mL
1 mL
1 cm3
Chapter 1: Measurements in
Chemistry
! Temperature
Water
in °C
0 oC
freezing point:
boiling point:
100 oC
Chapter 1: Measurements in
Chemistry
! Amount
Mole (mol); SI standard
1 mol contains 6.022!1023 molecules
(or other particles)
This is the Avogadro number
Structure of Matter: Atoms and
Molecules
Structure of Matter: Atoms and
Molecules
6 electrons
6 electrons
6 no+
6p
12
7 no+
6p
13
C
C
ISOTOPES OF CARBON
number of
neutrons
N = Mass - Z
atomic number
number of protons
Compounds and Chemical
Change
Most substances are polyatomic compounds
Chemical Change (Chemical Reaction):
old bonds break, new bonds form
Chemical Bonds
IONIC
electrons are
fully transferred
example:
Na
COVALENT
nonpolar
polar
electrons are shared
EVENLY
UNEVENLY
+ Cl
e-
"#
O
O
oxygen
Na+ +
Cl-
O
H
"+
H
"+
+
Molecular and Molar Weights
Monoatomic: Neon, Ne
20.18, MW = 20.18 g/mol
MW = sum of atomic weights
Molecules:
CH3OH: MW = 12.01 + 16.00 + 4!1.008 = 32.04 g/mol
Ionic Compounds:
CaCl2:
MW = 40.06 + 2!35.45 = 110.96 g/mol
Chemical Equations and
Stoichiometry
Cu + 4HNO3 $ Cu(NO3)2 + 2NO2 + 2H2O
balanced equation
shows relative amounts (in moles) of reactants and products
That is, their molar equivalents
Oxidation Numbers
Is a MODEL
useful for manipulations with redox reaction
where we assume that in compounds electrons are
transferred completely between elements according to certain
rules, and assign an imaginary charge.
+1
-2
H2SO4
Oxidation Numbers
Is a MODEL
useful for manipulations with redox reaction
where we assume that in compounds electrons are
transferred completely between elements according to certain
rules, and assign an imaginary charge.
+1
-2
H2SO4
+6
Density
Density
d(kg/m3) = m (kg)
V (m3)
d(g/L)
d(kg/m3) = m (kg)
V (m3)
d(g/L)
Amount
n(mol) =
m (g)
M (g/mol)
Density
d(kg/m3) = m (kg)
V (m3)
d(g/L)
Amount
n (mol) =
Density
m (g)
M (g/mol)
d(kg/m3) = m (kg)
V (m3)
Amount
n(mol) =
m (g)
M (g/mol)
Concentration
c(mol/L) =
n (mol)
V (L)
d(g/L)
Practice Problems
What is the mass of 1.35 M solution of copper (II) nitrate
containing 78 g of the salt? The density of the solution is
1.08 g/mL.
Practice Problems
Based on 4.120. When 50 mL of NaNO2 reacts with an
excess of potassium permanganate solution, MnO2
precipitates completely according to the following
equation:
KMnO4 + NaNO2 + H2O $ MnO2(s) + NaNO3 + KOH
If 435 mg of MnO2 precipitates, what is the concentration
of the original NaNO2 solution?
Answer: 0.15 M
Practice Problems
Based on 4.120. When 50 mL of NaNO2 reacts with an
excess of potassium permanganate solution, MnO2
precipitates completely according to the following
equation:
KMnO4 + NaNO2 + H2O $ MnO2(s) + NaNO3 + KOH
If 435 mg of MnO2 precipitates, what is the concentration
of the original NaNO2 solution?
Strategy:
1. Balance the equation (using the O.N. method)
2. Focus on coefficients, extract
necessary information
Practice Problems
*4.131. Starts with a story about renewable fuels.
(a) Write balanced equations for the complete combustion
of ethanol (C2H5OH) and octane (as gasoline) (C8H18).
(b) What mass of oxygen is required to burn completely
1.00 L of a mixture that is 90% gasoline (d = 0.742
g/mL) and 10% ethanol (d = 0.789 g/mL) by volume?
(c) If 1.00 mol of oxygen occupies 22.4 L, what volume of
oxygen is needed to burn 1.00 L of the mixture?
(d) Air is 20.9 % oxygen by volume. What volume of air is
needed to burn 1.00 L of the mixture?