All GRE Subject Test: Chemistry Resources
Example Questions
Example Question #1 : Acid Base Analysis
What is the of a 0.12M solution of
that has a pH of 5.1?
We can calculate the hydrogen ion concentration by using the following equation:
Plug in the given value for pH and solve:
Example Question #31 : Analytical Chemistry
Based on the equilibrium above, what does act as?
a base
radical
an anion
an acid
a catalyst
an acid
An acid is a substance that can donates a proton. The conjugate acid of a base is formed when the base accepts a proton. In this case, is the conjugate acid to the base
. This is because
accepts a hydrogen ion from the water molecule to form
, the conjugate acid.
Example Question #32 : Analytical Chemistry
Given the following equilibria, what is the hydroxide ion concentration of a solution containing
?
The for
is
Below is the acid-base equilibria of in an aqueous solution:
A solution of ammonia () is basic based on the chemical equation given. The
for this reaction is:
Based on the chemical equation, .
We can make the concentration of these species equal to :
The concentration is equal to:
has a low
so we can assume the following:
Plugging the values into the base dissociation constant equation gives:
Solve for :
Example Question #32 : Analytical Chemistry
Given the following equilibria, what is the hydrogen ion concentration of a solution containing
(benzoic acid)?
The for
is
.
Below is the acid-base equilibria of in an aqueous solution:
A solution of benzoic acid () is acidic based on the chemical equation given. The
for this reaction is:
Based on the chemical equation, .
We can make the concentration of these species equal to :
The concentration is equal to:
has a low
so we can assume the following:
Plugging the values into the base dissociation constant equation gives:
Solve for :
Example Question #292 : Gre Subject Test: Chemistry
Given the following equilibria, what is the hydronium ion concentration of a solution containing
?
The for
is
.
Below is the acid-base equilibria of in an aqueous solution:
A solution of is acidic based on the chemical equation given. The Ka for this reaction is:
Based on the chemical equation, .
We can make the concentration of these species equal to :
The concentration is equal to:
has a low
so we can assume the following:
Plugging the values into the base dissociation constant equation gives:
Solve for :
Example Question #1 : Oxidation Reduction Analysis
Which molecule would be considered a Lewis acid?
A lewis acid is an electron pair acceptor. would be considered a lewis acid based on the definition. Because
is electron-deficient based on its oxidation number, it is able to accept an electron pair.
Example Question #2 : Oxidation Reduction Analysis
Which of the following would be considered a Lewis base?
A lewis base is an electron pair donor. would be considered a lewis base based on the definition. Because
is electron rich based on its oxidation number, it is able to donate an electron pair to an electron deficient ion.
Example Question #3 : Oxidation Reduction Analysis
Which of the following types of reactions best describes the following reaction:
Double replacement
Combustion
Catalytic
Redox reaction
Combination
Redox reaction
A redox reaction is also known as an oxidation/reduction reaction. This type of reaction involves the transfer of electrons from on reactant to another. In this reaction, an electron is transferred from to
forming the products
and
. The substance that gains an electron is referred to as being reduced. The substance that loses an electron is referred to as being oxidized.
Example Question #303 : Gre Subject Test: Chemistry
What is the oxidation state of manganese in ?
In this compound oxygen has an oxidation number of . There are 4 oxygens, therefore the total oxidation number for the oxygens in
is:
. Potassium,
, is a group 1 metal and has an oxidation number of
. The sum of all oxidation number in a neutral compound such as
is zero. We will give the oxidation number of
equal to
:
Simplifying the above equation:
Rearranging to solve for :
Example Question #32 : Analytical Chemistry
What is the oxidation state of manganese in ?
In this compound oxygen has an oxidation number of . There are 4 oxygens, therefore the total oxidation number for the oxygens in
is:
. Potassium,
, is a group 1 metal and has an oxidation number of
. There are 3 potassium ions present in
, therefore the total oxidation number for the potassium ions is:
.The sum of all oxidation number in a neutral compound such as
is zero. We will give the oxidation number of
equal to
:
Simplifying the above equation:
Rearranging to solve for :
All GRE Subject Test: Chemistry Resources
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