Compounds - AP Chemistry
Card 0 of 238
What is the most acidic functional group on the amino acid cysteine? Cysteine has the chemical formula 
.
What is the most acidic functional group on the amino acid cysteine? Cysteine has the chemical formula
We know that by definition, all amino acids contain a carboxylic acid functional group (
), and an amino functional group (
). Therefore the additional functional group can only contain sulfur and hydrogen.
The amino functional group is slightly basic, and the carboylic acid functional group is slightly acidic. The -SH functional group will also be acidic, but because sulfur and oxygen are in the same group on the periodic table, the -SH group will have similar acidic properties to an -OH group, and alcohols are less acidic than carboxylic acids.
We know that by definition, all amino acids contain a carboxylic acid functional group (
The amino functional group is slightly basic, and the carboylic acid functional group is slightly acidic. The -SH functional group will also be acidic, but because sulfur and oxygen are in the same group on the periodic table, the -SH group will have similar acidic properties to an -OH group, and alcohols are less acidic than carboxylic acids.
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What is the percent by mass of bismuth in the compound 
?
What is the percent by mass of bismuth in the compound
The mass percentage of bismuth in the compound will be equal to the mass of bismuth in one mole of compound divided by the total molar mass of the compound.
Bismuth has a molar mass of 
. One mole of the compound would result in two moles of bismuth, a total of 417.96g.
Tellurium has a molar mass of 
. One mole of the compound would result in three moles of tellurium, a total of 382.8g.
Add the mass of bismuth and the mass of tellurium per mole to find the total molar mass.
Divide the mass of bismuth by the total molecular mass to find the percent by mass of bismuth in the compound.
The mass percentage of bismuth in the compound will be equal to the mass of bismuth in one mole of compound divided by the total molar mass of the compound.
Bismuth has a molar mass of
Tellurium has a molar mass of
Add the mass of bismuth and the mass of tellurium per mole to find the total molar mass.
Divide the mass of bismuth by the total molecular mass to find the percent by mass of bismuth in the compound.
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What is the percent by mass of carbon in acetic acid 
?
What is the percent by mass of carbon in acetic acid
The total molar mass of acetic acid is 
.
Carbon contributes 
total. Therefore, in a sample of 1 mole of acetic acid, there are 
of carbon. To find the percent by mass, we must divide the mass of carbon by the total molar mass of the compound.
The total molar mass of acetic acid is
Carbon contributes
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Calculate the percent by mass of each element in 
.
Calculate the percent by mass of each element in
The total molar mass of lead (II) sulfate is 
. Lead contributes 
, sulfur contributes 
, and oxygen contributes 
.
The percent by mass of each element in the compound is found by dividing the mass contribution of that element by the total molar mass of the compound.
The total molar mass of lead (II) sulfate is
The percent by mass of each element in the compound is found by dividing the mass contribution of that element by the total molar mass of the compound.
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What percent by mass of 
is chlorine?
What percent by mass of
The molar mass of calcium chloride is 
. Chlorine has two moles per one mole of . Therefore, chloride contributes 70.9g to the total molecular mass.
To find the percent by mass of chlorine in calcium chloride, divide the contribution of chlorine by the total molar mass.
The molar mass of calcium chloride is
To find the percent by mass of chlorine in calcium chloride, divide the contribution of chlorine by the total molar mass.
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Calculate the percent by mass of each element in 
.
Calculate the percent by mass of each element in
The total mass of one mole of aluminum (II) chromate is calculated by:
Aluminum, chromate, and oxygen contribute 
and 
respectively. Therefore, we can divide each contribution by the total molecular mass to determine percentages by mass.
The total mass of one mole of aluminum (II) chromate is calculated by:
Aluminum, chromate, and oxygen contribute
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What is the percent by mass of hydrogen in 
?
What is the percent by mass of hydrogen in
The total mass of 
is 
and calculated by:
You can then divide hydrogen's contribution by the total molecular mass in order to find the percent mass.
The total mass of
You can then divide hydrogen's contribution by the total molecular mass in order to find the percent mass.
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What percent of the overall mass is represented by the cation(s) in 
?
What percent of the overall mass is represented by the cation(s) in
The total molar mass of 
is 
. Cesium has a +1 charge when the compound is dissolved in solution and is, thus, the cation.
Cesium contributes 265.8g to the total molecular mass.
We can find the percent by mass of cesium by dividing the mass of cesium by the total molecular mass.
The total molar mass of
Cesium contributes 265.8g to the total molecular mass.
We can find the percent by mass of cesium by dividing the mass of cesium by the total molecular mass.
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Which of the following is the alcohol functional group?
Which of the following is the alcohol functional group?
The alcohol functional group is -OH
The alcohol functional group is -OH
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Which of the following functional groups is an amide?
Which of the following functional groups is an amide?
Amides contain both oxygen and nitrogen in the functional group. The oxygen forms a double bond with a carbon, and the carbon bonds to a nitrogen. This forms the structure 
, where the nitrogen is also bound to the carbon.
is an alcohol functional group.
is an amine functional group.
is a carboxylic acid functional group.
is an aldehyde functional group.
Amides contain both oxygen and nitrogen in the functional group. The oxygen forms a double bond with a carbon, and the carbon bonds to a nitrogen. This forms the structure
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Which one of the following organic functional groups does not contain a carbon-oxygen double bond?
Which one of the following organic functional groups does not contain a carbon-oxygen double bond?
A nitrile group contains a carbon-nitrogen triple bond, while all of the other groups contain a carbon-oxygen double bond.
Nitrile: 
Ester: 
Ketone: 
Carboxylic acid: 
Aldehyde: 
A nitrile group contains a carbon-nitrogen triple bond, while all of the other groups contain a carbon-oxygen double bond.
Nitrile:
Ester:
Ketone:
Carboxylic acid:
Aldehyde:
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Which of the following is an organic compound?
Which of the following is an organic compound?
An organic compound is typically defined as one that contains carbon. Though there some small exceptions to this rule (for example, cyanide is not considered organic), in general most compounds follow it.
Though water, oxygen, and sodium chloride, may seem organic, they are not for they do not contain any covalent bonds to carbon. The only gievn compound that contains carbon is glucose, a sugar.
An organic compound is typically defined as one that contains carbon. Though there some small exceptions to this rule (for example, cyanide is not considered organic), in general most compounds follow it.
Though water, oxygen, and sodium chloride, may seem organic, they are not for they do not contain any covalent bonds to carbon. The only gievn compound that contains carbon is glucose, a sugar.
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A chemist is trying to find the identity of a compound. She knows that the compound has a molecular weight of 
, and also that it consists of 
carbon, 
hydrogen, and 
oxygen by mass. What are the empirical and molecular formulas, respectively, for this compound?
A chemist is trying to find the identity of a compound. She knows that the compound has a molecular weight of
The simplest way to begin these types of problems is to assume that we are starting out with 100 grams of the sample compound. This allows us to simplify things, since we know the mass percentages of the elements that make up out unknown compound.
Next, we must convert amount of each element from grams into moles.
This gives us a formula of 
Now, we need to simplify this formula by dividing each of the terms by the greatest common denominator, 3.33, which gives us:
This is our empirical formula. To obtain the molecular formula, we must first find the mass of our empirical formula, which is 
.
Next, we need to divide the molecular weight of the compound by the empirical weight to obtain an integer of 
. Finally, we multiply the empirical formula by this integer in order to obtain the molecular formula, which is:
The simplest way to begin these types of problems is to assume that we are starting out with 100 grams of the sample compound. This allows us to simplify things, since we know the mass percentages of the elements that make up out unknown compound.
Next, we must convert amount of each element from grams into moles.
This gives us a formula of
Now, we need to simplify this formula by dividing each of the terms by the greatest common denominator, 3.33, which gives us:
This is our empirical formula. To obtain the molecular formula, we must first find the mass of our empirical formula, which is
Next, we need to divide the molecular weight of the compound by the empirical weight to obtain an integer of
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What are the mass percents of C, H, and O, respectively, in a molecule of glucose monomer (
)?
What are the mass percents of C, H, and O, respectively, in a molecule of glucose monomer (
On average, the molar masses of carbon, hydrogen, and oxygen are approximately 
, 
, and 
, respectively.
The molar mass of a molecule of glucose is:
Each term added in the previous step is the mass of each element present in a mole of glucose, so the mass percent of its components are found by dividing their respective contributions to the molar mass by the molar mass:
On average, the molar masses of carbon, hydrogen, and oxygen are approximately
The molar mass of a molecule of glucose is:
Each term added in the previous step is the mass of each element present in a mole of glucose, so the mass percent of its components are found by dividing their respective contributions to the molar mass by the molar mass:
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According to VSEPR theory, for the ammonium ion (
), the electron-pair geometry is __________ and the molecular geometry is __________.
According to VSEPR theory, for the ammonium ion (
Both the electron-pair and molecular geometries of ammonium are tetrahedral, as opposed to ammonia (
), in which the electron-pair geometry is tetrahedral, but the molecular geometry is trigonal pyramidal. As evidenced below:
Ammonia:
Note that the difference in geometry arises in the presence of the lone pair on nitrogen in ammonia. The lone pair only contributes to molecular geometry, but does not contribute to electron-pair geometry. Bonding electrons, however, contribute to both electron and molecular geometries.
Ammonium:
In ammonium, the lone pair seen in ammonia is shared in a bond with an additional hydrogen atom.
Both the electron-pair and molecular geometries of ammonium are tetrahedral, as opposed to ammonia (
Ammonia:
Note that the difference in geometry arises in the presence of the lone pair on nitrogen in ammonia. The lone pair only contributes to molecular geometry, but does not contribute to electron-pair geometry. Bonding electrons, however, contribute to both electron and molecular geometries.
Ammonium:
In ammonium, the lone pair seen in ammonia is shared in a bond with an additional hydrogen atom.
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What is the oxidation state of manganese (
) in the polyatomic permanganate anion (
)?
What is the oxidation state of manganese (
When assigning oxidation states to elements of a given compound, non-transition metal elements are assigned specific oxidation states corresponding to their group number and valence relative to a complete octet.
Group 1 elements have 1 valence electron and an oxidation state of +1.
Group 2 elements have 2 valence electrons and an oxidation state of +2.
Group 8 elements (the noble gases) have a complete octet, thus their assigned oxidation state is 0.
Group 7 elements (halogens) have 7 valence electrons and an oxidation state of -1.
Group 6 elements such as oxygen have 6 valence electrons and an oxidation state of -2.
Permanganate has 4 oxygen atoms and an overall charge of -1. The oxidation state of the 
atom may be found by first calculating the combined oxidation state of the oxygen atoms:
and finding the difference between their combined oxidation state and the overall charge of the ion (-1):
When assigning oxidation states to elements of a given compound, non-transition metal elements are assigned specific oxidation states corresponding to their group number and valence relative to a complete octet.
Group 1 elements have 1 valence electron and an oxidation state of +1.
Group 2 elements have 2 valence electrons and an oxidation state of +2.
Group 8 elements (the noble gases) have a complete octet, thus their assigned oxidation state is 0.
Group 7 elements (halogens) have 7 valence electrons and an oxidation state of -1.
Group 6 elements such as oxygen have 6 valence electrons and an oxidation state of -2.
Permanganate has 4 oxygen atoms and an overall charge of -1. The oxidation state of the
and finding the difference between their combined oxidation state and the overall charge of the ion (-1):
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What is the name for the following polyatomic ion: 
(also written 
)?
What is the name for the following polyatomic ion:
(also written as 
) is the formula for the acetate ion. Most polyatomic ions tend to follow certain naming trends, but acetate is one of the ions that does not follow those naming trends, so memorize this one since it shows up frequently in chemistry.
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Which of the following is an organic compound?
Which of the following is an organic compound?
An organic compound is typically defined as one that contains carbon. Though there some small exceptions to this rule (for example, cyanide is not considered organic), in general most compounds follow it.
Though water, oxygen, and sodium chloride, may seem organic, they are not for they do not contain any covalent bonds to carbon. The only gievn compound that contains carbon is glucose, a sugar.
An organic compound is typically defined as one that contains carbon. Though there some small exceptions to this rule (for example, cyanide is not considered organic), in general most compounds follow it.
Though water, oxygen, and sodium chloride, may seem organic, they are not for they do not contain any covalent bonds to carbon. The only gievn compound that contains carbon is glucose, a sugar.
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What is the percent by mass of bismuth in the compound ?
What is the percent by mass of bismuth in the compound
The mass percentage of bismuth in the compound will be equal to the mass of bismuth in one mole of compound divided by the total molar mass of the compound.
Bismuth has a molar mass of . One mole of the compound would result in two moles of bismuth, a total of 417.96g.
Tellurium has a molar mass of . One mole of the compound would result in three moles of tellurium, a total of 382.8g.
Add the mass of bismuth and the mass of tellurium per mole to find the total molar mass.
Divide the mass of bismuth by the total molecular mass to find the percent by mass of bismuth in the compound.
The mass percentage of bismuth in the compound will be equal to the mass of bismuth in one mole of compound divided by the total molar mass of the compound.
Bismuth has a molar mass of
Tellurium has a molar mass of
Add the mass of bismuth and the mass of tellurium per mole to find the total molar mass.
Divide the mass of bismuth by the total molecular mass to find the percent by mass of bismuth in the compound.
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Which one of the following organic functional groups does not contain a carbon-oxygen double bond?
Which one of the following organic functional groups does not contain a carbon-oxygen double bond?
A nitrile group contains a carbon-nitrogen triple bond, while all of the other groups contain a carbon-oxygen double bond.
Nitrile:
Ester:
Ketone:
Carboxylic acid:
Aldehyde:
A nitrile group contains a carbon-nitrogen triple bond, while all of the other groups contain a carbon-oxygen double bond.
Nitrile:
Ester:
Ketone:
Carboxylic acid:
Aldehyde:
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