ACT Science : How to find conflicting viewpoints in chemistry

Study concepts, example questions & explanations for ACT Science

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Example Question #181 : Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

Which theory supports the concept that acid-base reactions are based on donations between acids and bases?

Possible Answers:

Theory 3 only

Theories 2 and 3

Theories 1, 2 and 3

Theory 2 only

Correct answer:

Theories 2 and 3

Explanation:

Both theory 2 and theory 3 base their defintion of acid-base reactions on the concept of donation. Theory 2 concerns the donation of hydrogen ions from acids to bases, while theory 3 concerns the donation of electron pairs from bases to acids. Theory 1 never discusses the idea of donation.

Example Question #31 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

Which theory would consider boron trifluoride  an acid?

Possible Answers:

Theories 1, 2 and 3

Theory 1 only

Theory 2 only

Theory 3 only

Correct answer:

Theory 3 only

Explanation:

Boron trifluoride has no hydrogen in the compound, and therefore cannot dissociate  in water or donate to a base. It can only be part of a acid-base reaction through accepting an electron pair, so only theory 3 would consider it an acid.

Example Question #31 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

Which theory argues that salts are a necessary product of an acid-base reaction?

Possible Answers:

Theory 1 only

Theories 1, 2 and 3

Theories 1 and 2

Theory 3 only

Correct answer:

Theory 1 only

Explanation:

Only theory 1 argues that an acid-base reaction always produces water and salt. Theory 2 and theory 3 do not specify the results of an acid-base reaction, and theory 3 doesn't even require hydrogen for an acid-base reaction (which means an acid-base reaction couldn't produce water).

Example Question #31 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

According to theory 2, what is the conjugate base of  for the following reaction?

Possible Answers:

There is no conjugate base of 

Correct answer:

Explanation:

The conjugate base is the original acid of the acid-base reaction minus its hydrogen ion. The original acid of this reaction is , which donates its hydrogen ion to  and becomes .

Example Question #31 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

What statement would theory 3 consider most correct?

Possible Answers:

Acid-base reactions produce unstable compounds

Acid-base reactions often take too long to form stable bonds

Acid-base reactions are a result of the desire of compounds to complete their octets

Theory 3 would support all of these answers

Correct answer:

Acid-base reactions are a result of the desire of compounds to complete their octets

Explanation:

Theory 3 is based on the donation of electron pairs to complete the electron octets of compounds. These reactions would actually tend to produce more stable compounds, and the length of the reaction is not discussed by theory 3.

Example Question #31 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

Which theory would not support the classification of an acid-base reaction occuring between pure compounds that are not dissolved in solutions?

Possible Answers:

Theories 2 and 3

Theory 3 only

Theory 2 only

Theory 1 only

Correct answer:

Theory 1 only

Explanation:

Only theory 1 specifies that acid-base reactions must take place in an aqueous solution. Theory 2 and theory 3 also include the possibility of pure acids and bases reacting outside of solutions.

Example Question #31 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

According to theory 1, how would a scientist determine whether a substance was an acid or not?

Possible Answers:

By mixing the solid substance with a pure base to create a reaction

By determining how many electrons the substance has through the periodic table

By mixing the substance with salt and recording its temperature

By measuring the level of hydrogen and hydroxide ions of the substance in water

Correct answer:

By measuring the level of hydrogen and hydroxide ions of the substance in water

Explanation:

Theory 1 states the only way to determine if a substance is an acid is to submerge it in water and measure either an increase in the level of hydrogen ions or a decrease in the level of hydroxide ions. Determining the number of electrons would only be useful for theory 3, and mixing the substance with a pure base would only work with theory 2 and theory 3 since theory 1 specifies that acid-base reactions only take place in a solution. Recording temperatures is not discussed by any of the theories.

Example Question #191 : Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

Which theory supports this statement: “The transfer of protons is a necessary part of an acid-base reaction."

Possible Answers:

Theories 1 and 2

Theory 2 only

Theory 3 only

Theory 1 only

Correct answer:

Theories 1 and 2

Explanation:

Both theory 1 and theory 2 focus on the transfer of hydrogen protons in acid-base reactions. Theory 3 states an acid-base reaction can occur based on the process of the donation of electrons, meaning no protons have to be transferred.

Example Question #33 : How To Find Conflicting Viewpoints In Chemistry

Acids and bases are chemical substances that react with each other and certain other elements to produce compounds like salts. Chemists have discussed the unique reaction between acids and bases significantly, here are three major theories that attempt to explain how acids and bases react.

Theory 1: The Arrhenius acid/base theory focuses on hydrogen, and how acids and bases neutralize each other to form salt and water. Acids dissociate in a solution into hydrogen ions , while bases dissociate in a solution into hydroxide ions . An acid, when introduced to water, will increase the amount of hydrogen ions present (which can be observed as hydronium ions), or decrease the amount of hydroxide ions present. Conversely, a base will either increase the amount of hydroxide ions or decrease the amount of hydronium ions when introduced to water. This is the only way to determine if a substance is an acid or base. When an acid is introduced to a base, a neutralization reaction occurs when the protons  of the acid combine with the hydroxide ions  of the base to form water and a salt byproduct.

Theory 2: The Bronsted-Lowry theory concerns the donation of hydrogen ions from acids to bases and the formation of conjugate pairs. This theory defines acids as the substance that donates a proton, and bases as the substance that accepts the proton. Because reactions can be reversible, acids that have their hydrogen ion removed become that acid’s conjugate base, while bases that receive that hydrogen ion become the original base’s conjugate acid. This is true because if the reaction is reversed, the former-acid with its missing proton will be receiving the hydrogen ion (making it the base) and the former-base with the additional proton will be donating it (making it the acid). Reactions then produce new bases and acids, and do not neutralize to produce salts and water. This acid-base theory does not require a solvent.

Theory 3: The Lewis theory discards the concern with hydrogen ions and focuses on electron-pair donation. According to this theory, acids are substances that can receive an electron pair whereas bases are substances that can donate an electron pair. This broadens the consideration of what is a base or an acid even further, eliminating the need to define substances based on their use of a hydrogen ion. Compounds that have vacancies in their electron octets can be considered Lewis acids, and compounds with extra electrons in their octets can be considered Lewis bases.

Suppose theory 2 is proven correct and theories 1 and 3 are debunked. What would be the result of this?

Possible Answers:

Acid-base reactions would no longer be considered part of chemistry

Acid-base reactions would only be conducted in solutions

Acid-base reactions without hydrogen ions would be discounted

None of the answers are true

Correct answer:

Acid-base reactions without hydrogen ions would be discounted

Explanation:

Theory 2 requires hydrogen ions to be donated for an acid-base reaction to occur. If Theory 2 was proven solely correct, a reaction between substances without the donation of hydrogen ions would not be considered an acid-base reaction. If only theory 1 was proved true, then only those reactions involving a change in the concentration of hydrogen and/or hydroxide ions in water would be considered acid-base reactions. Acid-base reactions would still be a part of chemistry.

Example Question #32 : How To Find Conflicting Viewpoints In Chemistry

The Environmental Protection Agency compiled the following information about heavy metals in drinking water. Heavy metals are toxic, and thus must be monitored very closely. All amounts are given in parts per billion (ppb), a common measurement of concentration for trace contaminants. Figure 1 shows total heavy metal contamination in each city as a makeup of various percentages of specific contaminants. Figure 2 shows specific amounts of contaminants (with the same color coding) in ppb as well as total contamination level in ppb.

Piechart

Figure 1

Bar graph

Figure 2

The Environmental Protection Agency (EPA) limits the concentration of antimony to 6ppb. Which city is most likely in violation of this statute?

Possible Answers:

Fargo

Miami

Boston

Chicago

Correct answer:

Boston

Explanation:

Figure 2 shows contaminants in parts per billion (ppb). We are interested in antimony, which is shown here in red.  Note that the red bar for Boston comes up past 6ppb, and that subtracting the small amount of total contaminant attributed to lead, in orange, does not place Boston's total antimony concentration under 6ppb. 

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