Sample Problems
List what type the following reactions are:
1) NaOH + KNO3 --> NaNO3 + KOH
2) CH4 + 2 O2 --> CO2 + 2 H2O
3) 2 Fe + 6 NaBr --> 2 FeBr3 + 6 Na
4) CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4
5) NH4OH + HBr --> H2O + NH4Br
6) Pb + O2 --> PbO2
7) Na2CO3 --> Na2O + CO2
Monday, March 3, 2008
TYPES OF CHEMICAL REACTIONS
All chemical reactions can be placed into one of six categories. Here they are, in no particular order:
1) Combustion: A combustion reaction is when oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic, meaning they produce heat. An example of this kind of reaction is the burning of napthalene:
C10H8 + 12 O2 ---> 10 CO2 + 4 H2O
--------------------------------------------------------------------------------
2) Synthesis: A synthesis reaction is when two or more simple compounds combine to form a more complicated one. These reactions come in the general form of:
A + B ---> AB
One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide:
8 Fe + S8 ---> 8 FeS
--------------------------------------------------------------------------------
3) Decomposition: A decomposition reaction is the opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones. These reactions come in the general form:
AB ---> A + B
One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas:
2 H2O ---> 2 H2 + O2
--------------------------------------------------------------------------------
4) Single displacement: This is when one element trades places with another element in a compound. These reactions come in the general form of:
A + BC ---> AC + B
One example of a single displacement reaction is when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas:
Mg + 2 H2O ---> Mg(OH)2 + H2
--------------------------------------------------------------------------------
5) Double displacement: This is when the anions and cations of two different molecules switch places, forming two entirely different compounds. These reactions are in the general form:
AB + CD ---> AD + CB
One example of a double displacement reaction is the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate:
Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3
--------------------------------------------------------------------------------
6) Acid-base: This is a special kind of double displacement reaction that takes place when an acid and base react with each other. The H+ ion in the acid reacts with the OH- ion in the base, causing the formation of water. Generally, the product of this reaction is some ionic salt and water:
HA + BOH ---> H2O + BA
One example of an acid-base reaction is the reaction of hydrobromic acid (HBr) with sodium hydroxide:
HBr + NaOH ---> NaBr + H2O
All chemical reactions can be placed into one of six categories. Here they are, in no particular order:
1) Combustion: A combustion reaction is when oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic, meaning they produce heat. An example of this kind of reaction is the burning of napthalene:
C10H8 + 12 O2 ---> 10 CO2 + 4 H2O
--------------------------------------------------------------------------------
2) Synthesis: A synthesis reaction is when two or more simple compounds combine to form a more complicated one. These reactions come in the general form of:
A + B ---> AB
One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide:
8 Fe + S8 ---> 8 FeS
--------------------------------------------------------------------------------
3) Decomposition: A decomposition reaction is the opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones. These reactions come in the general form:
AB ---> A + B
One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas:
2 H2O ---> 2 H2 + O2
--------------------------------------------------------------------------------
4) Single displacement: This is when one element trades places with another element in a compound. These reactions come in the general form of:
A + BC ---> AC + B
One example of a single displacement reaction is when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas:
Mg + 2 H2O ---> Mg(OH)2 + H2
--------------------------------------------------------------------------------
5) Double displacement: This is when the anions and cations of two different molecules switch places, forming two entirely different compounds. These reactions are in the general form:
AB + CD ---> AD + CB
One example of a double displacement reaction is the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate:
Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3
--------------------------------------------------------------------------------
6) Acid-base: This is a special kind of double displacement reaction that takes place when an acid and base react with each other. The H+ ion in the acid reacts with the OH- ion in the base, causing the formation of water. Generally, the product of this reaction is some ionic salt and water:
HA + BOH ---> H2O + BA
One example of an acid-base reaction is the reaction of hydrobromic acid (HBr) with sodium hydroxide:
HBr + NaOH ---> NaBr + H2O
PRACTICE..
Write the correct name for:
1) MgS
2) KBr
3) Ba3N2
4) Al2O3
5) NaI
6) SrF2
7) Li2S
8) RaCl2
9) CaO
10) AlP
Write the correct formula for:
1) magnesium oxide
2) lithium bromide
3) calcium nitride
4) aluminum sulfide
5) potassium iodide
6) strontium chloride
7) sodium sulfide
8) radium bromide
9) magnesium sulfide
10) aluminum nitride
11) CuCl2
12) CuBr
13) PbO
14) Fe2S3
15) PbCl2
16) SnO
17) Cu2O
18) PbO2
19) FeO
20) SnO2
Write the correct formula for:
1) iron(II) chloride
2) copper(I) sulfide
3) lead(IV) iodide
4) tin(II) fluoride
5) mercury(I) bromide
6) tin(II) oxide
7) chromium(III) oxide
8) gold(I) iodide
9) manganese(II) nitride
10) cobalt(III) phosphide
Name the following acids:
1) H3PO4
2) H2CO3
3) H2SO4
4) HIO3
5) HF
6) HNO2
Write the formula for these acids:
7) hydrobromic acid
8) hydrocyanic acid [this has a twist in it]
9) nitric acid
10) sulfurous acid
11) phosphorous acid
12) acetic acid
Write the correct name for:
1) MgS
2) KBr
3) Ba3N2
4) Al2O3
5) NaI
6) SrF2
7) Li2S
8) RaCl2
9) CaO
10) AlP
Write the correct formula for:
1) magnesium oxide
2) lithium bromide
3) calcium nitride
4) aluminum sulfide
5) potassium iodide
6) strontium chloride
7) sodium sulfide
8) radium bromide
9) magnesium sulfide
10) aluminum nitride
11) CuCl2
12) CuBr
13) PbO
14) Fe2S3
15) PbCl2
16) SnO
17) Cu2O
18) PbO2
19) FeO
20) SnO2
Write the correct formula for:
1) iron(II) chloride
2) copper(I) sulfide
3) lead(IV) iodide
4) tin(II) fluoride
5) mercury(I) bromide
6) tin(II) oxide
7) chromium(III) oxide
8) gold(I) iodide
9) manganese(II) nitride
10) cobalt(III) phosphide
Name the following acids:
1) H3PO4
2) H2CO3
3) H2SO4
4) HIO3
5) HF
6) HNO2
Write the formula for these acids:
7) hydrobromic acid
8) hydrocyanic acid [this has a twist in it]
9) nitric acid
10) sulfurous acid
11) phosphorous acid
12) acetic acid
Monday, December 17, 2007
grahams law of effusion
Gases : Graham's Laws of Diffusion and Effusion
Only a few physical properties of gases depends on the identity of the gas.
Diffusion - The rate at which two gases mix.
Effusion - The rate at which a gas escapes through a pinhole into a vacuum. Thomas Graham
Graham's Law of Diffusion
The rate at which gases diffuse is inversely proportional to the square root of their densities.
Since volumes of different gases contain the same number of particles (see Avogadro's Hypothesis), the number of moles per liter at a given T and P is constant. Therefore, the density of a gas is directly proportional to its molar mass (MM).
Graham's Law of Effusion
The rate of effusion of a gas is inversely proportional to the square root of either the density or the molar mass of the gas.
The time required for 25-mL samples of different gasses to diffuse through a pinhole into a vacuum.
The Kinetic Molecular Theory and Graham's Law
Since KEavg is dependent only upon T, two different gases at the same temperature must have the same KEavg.
Simplify the equation by multiplying both sides by two:
Rearrange to give the following:
Take the square root of both sides to obtain the following relationship between the ratio of the velocities of the gases and the square root of the ratio of their molar masses:
This equation states that the velocity (rate) at which gas molecules move is inversely proportional to the square root of their molar masses.
Next: "Deviation from Ideal Gas Behavior: Van der Waals Equation"
Only a few physical properties of gases depends on the identity of the gas.
Diffusion - The rate at which two gases mix.
Effusion - The rate at which a gas escapes through a pinhole into a vacuum. Thomas Graham
Graham's Law of Diffusion
The rate at which gases diffuse is inversely proportional to the square root of their densities.
Since volumes of different gases contain the same number of particles (see Avogadro's Hypothesis), the number of moles per liter at a given T and P is constant. Therefore, the density of a gas is directly proportional to its molar mass (MM).
Graham's Law of Effusion
The rate of effusion of a gas is inversely proportional to the square root of either the density or the molar mass of the gas.
The time required for 25-mL samples of different gasses to diffuse through a pinhole into a vacuum.
The Kinetic Molecular Theory and Graham's Law
Since KEavg is dependent only upon T, two different gases at the same temperature must have the same KEavg.
Simplify the equation by multiplying both sides by two:
Rearrange to give the following:
Take the square root of both sides to obtain the following relationship between the ratio of the velocities of the gases and the square root of the ratio of their molar masses:
This equation states that the velocity (rate) at which gas molecules move is inversely proportional to the square root of their molar masses.
Next: "Deviation from Ideal Gas Behavior: Van der Waals Equation"
combined gas law
Combined gas law
From Wikipedia, the free encyclopedia
The combined gas law is a gas law which combines Charles's law, Boyle's law, and Gay-Lussac's law. These laws each relate one thermodynamic variable to another mathematically while holding everything else constant. Charles's law states that volume and temperature are directly proportional to each other while pressure is held constant. Boyle's law asserts that pressure and volume are inversely proportional to each other at fixed temperature. Finally Gay-Lussac's law introduces a direct proportionality between temperature and pressure at constant volume. The inter-dependence of these variables is shown in the combined gas law, which states that:
“
The ratio between the pressure-volume constant and the temperature of a system remains constant.
”
This can be stated mathematically as
where:
P is the pressure.
V is the volume.
T is the temperature (measured in kelvin).
k is a constant with units of energy divided by temperature.
For comparing the same substance under two different sets of conditions, the law can be written as:
The addition of Avogadro's law to the combined gas law yields the ideal gas law.
Retrieved from "http://en.wikipedia.org/wiki/Combined_gas_law"
From Wikipedia, the free encyclopedia
The combined gas law is a gas law which combines Charles's law, Boyle's law, and Gay-Lussac's law. These laws each relate one thermodynamic variable to another mathematically while holding everything else constant. Charles's law states that volume and temperature are directly proportional to each other while pressure is held constant. Boyle's law asserts that pressure and volume are inversely proportional to each other at fixed temperature. Finally Gay-Lussac's law introduces a direct proportionality between temperature and pressure at constant volume. The inter-dependence of these variables is shown in the combined gas law, which states that:
“
The ratio between the pressure-volume constant and the temperature of a system remains constant.
”
This can be stated mathematically as
where:
P is the pressure.
V is the volume.
T is the temperature (measured in kelvin).
k is a constant with units of energy divided by temperature.
For comparing the same substance under two different sets of conditions, the law can be written as:
The addition of Avogadro's law to the combined gas law yields the ideal gas law.
Retrieved from "http://en.wikipedia.org/wiki/Combined_gas_law"
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