"Chemistry Cheat Sheet"

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mass is the amount of something...
weight is how much gravity is pulling on the mass.
(Weight will be proportional to the mass at a given spot.)
Mass is what we REALLY want to use... measured in grams.
4 • Matter
You use a balance to measure mass... you compare your
Mass & Weight -- Two Properties of Matter
object with objects of known mass.
(1 of 8)
Weight is measured with a scale (like your bathroom scale
or the scale at the grocery store). If there is no gravity, it
doesn’t work. Note: electronic balances are really scales!
1 kg
2.205 lbs
You convert mass / weight using:
or
2.205 lbs
1 kg
Matter
Energy
Pure Substances
Mixtures
Compounds
Elements
Homogeneous
Heterogeneous
4 • Matter
This chart should help you sort out these similar terms.
Pure Substances, Elements, & Compounds
Be able to use chemical symbols to represent elements and
Homogeneous & Heterogeneous Mixtures
compounds. For example...
(2 of 8)
CuSO
•5H
O, a hydrate, contains 21 atoms & 4 elements.
4
2
Memorize the 7 elements that exist in diatomic molecules:
HONClBrIF or BrINClHOF or “H and the 6 that make a 7
starting with element #7”
Mixtures are substances the are NOT chemically combined...
so if you want to separate them, you need to exploit
differences in their PHYSICAL properties.
Filtration: some components of the mixture dissolve &
some do not. Filtrate is what passes through the filter.
4 • Matter
Distillation: some components vaporize at different
Separating Mixtures by Filtration,
temperatures or one component may not vaporize at all
Distillation, and Chromatography
(e.g.: salt+water) complete separation may not be
(3 of 8)
possible.
Chromatography: differences in solubility vs. adhesion to
the substrate. Substratemay be filter paper (paper
chromatography), or other substances, GLC, TLC,
HPLC, column, etc.
Extensive properties depend on the amount of substance.
We measure these properties frequently... (mass &
volume... mostly).
Intensive properties are independent of the size of the
4 • Matter
sample. These are useful for identifying substances...
Mass, Volume, and Density
(melting point, boiling point, density, etc.)
Intensive vs. Extensive Properties
mass
(4 of 8)
It is interesting that an intensive property, density =
volume
is the ratio of two extensive properties... the size of the
sample sort of “cancels out.” Be able to do density problems
(3 variables). See Sample Problems on pages 72 & 73
mass is the amount of something...
weight is how much gravity is pulling on the mass.
(Weight will be proportional to the mass at a given spot.)
Mass is what we REALLY want to use... measured in grams.
4 • Matter
You use a balance to measure mass... you compare your
Mass & Weight -- Two Properties of Matter
object with objects of known mass.
(1 of 8)
Weight is measured with a scale (like your bathroom scale
or the scale at the grocery store). If there is no gravity, it
doesn’t work. Note: electronic balances are really scales!
1 kg
2.205 lbs
You convert mass / weight using:
or
2.205 lbs
1 kg
Matter
Energy
Pure Substances
Mixtures
Compounds
Elements
Homogeneous
Heterogeneous
4 • Matter
This chart should help you sort out these similar terms.
Pure Substances, Elements, & Compounds
Be able to use chemical symbols to represent elements and
Homogeneous & Heterogeneous Mixtures
compounds. For example...
(2 of 8)
CuSO
•5H
O, a hydrate, contains 21 atoms & 4 elements.
4
2
Memorize the 7 elements that exist in diatomic molecules:
HONClBrIF or BrINClHOF or “H and the 6 that make a 7
starting with element #7”
Mixtures are substances the are NOT chemically combined...
so if you want to separate them, you need to exploit
differences in their PHYSICAL properties.
Filtration: some components of the mixture dissolve &
some do not. Filtrate is what passes through the filter.
4 • Matter
Distillation: some components vaporize at different
Separating Mixtures by Filtration,
temperatures or one component may not vaporize at all
Distillation, and Chromatography
(e.g.: salt+water) complete separation may not be
(3 of 8)
possible.
Chromatography: differences in solubility vs. adhesion to
the substrate. Substratemay be filter paper (paper
chromatography), or other substances, GLC, TLC,
HPLC, column, etc.
Extensive properties depend on the amount of substance.
We measure these properties frequently... (mass &
volume... mostly).
Intensive properties are independent of the size of the
4 • Matter
sample. These are useful for identifying substances...
Mass, Volume, and Density
(melting point, boiling point, density, etc.)
Intensive vs. Extensive Properties
mass
(4 of 8)
It is interesting that an intensive property, density =
volume
is the ratio of two extensive properties... the size of the
sample sort of “cancels out.” Be able to do density problems
(3 variables). See Sample Problems on pages 72 & 73
Equations to symbolize changes: reactants → products
Physical Properties can be measured from a sample of the
substance alone... (density, MP, BP, color, etc.)
Chemical Properties are measured when a sample is mixed
4 • Matter
with another chemical (reaction with acid, how does it
Physical and Chemical Properties
burn in O
)
2
Physical and Chemical Changes
Physical Changes imply that no new substances are being
(5 of 8)
formed (melting, boiling, dissolving, etc.)
Chemical Changes imply the substance is decomposing
into new substances or mixing with another chemical to
form new substances. This change is accompanied by heat,
light, gas formation, color changes, etc.
Conservation means the quantity does not change during a
reaction. If you carefully measure the reactants before a
reaction and the products after the reaction, no mass is
gained or lost. This is called Conservation of Mass.
4 • Matter
Know your symbols of the elements (make Flash Cards).
Conservation of Mass
Be careful with the spelling of:
Symbols of the Elements
Cl, chlorine F, fluorine Ni, nickel
(6 of 8)
Mn, manganese vs. Mg, magnesium
Recall that many of the symbols come from the Latin name.
Refer to page 80 for a nice listing with the Latin names.
In the atmosphere:
78% nitrogen gas, N
2
21% oxygen gas, O
2
<1% argon gas, Ar
4 • Matter
In the earth’s crust :
Relative Abundance of Elements
Most of the crust is made up of SiO
(quartz, sand, glass)
2
(7 of 8)
46.7% oxygen (mostly combined with silicon)
27.7% silicon (mostly combined with oxygen)
8.1% aluminum (in combined form)
5.0% iron (in combined form)
In the universe:
almost all hydrogen gas, H
... then He (fusion product)
2
Name: Dephlogisticated Air - Oxygen gas, O
2
Recipe: Catalytic Decomposition of hydrogen peroxide
(H
O
) by yeast
2
2
Test:
Glowing Splint Test (oxygen supports combustion)
4 • Matter
Name: Inflammable Air - Hydrogen gas, H
2
Natural History of Airs Lab
Recipe: Drano™ (NaOH) + Al° → Na
+
3–
+ AlO
+ H
2
The Chemistry of the Airs, the Recipes, and the
→ H
Test:
Burning Splint Test (H
+ O
O + energy)
2
2
2
Tests for the Three Gases
(8 of 8)
Name: Fixed Air - Carbon Dioxide gas, CO
2
Recipe: chalk (CaCO
) + vinegar (acetic acid) (HC
H
O
)
3
2
3
2
→ H
O + CO
+ Ca(C
H
O
)
2
2
2
3
2
2
→ CaCO
Test:
Limewater (Ca(OH)
+ CO
(s) + H
O
2
2
3
2
Page of 2