Question 1

Consider the following molecules. What is the relationship between the degree to which the molecule is oxidized and its polarity?

Accepted Answer

The answer of Consider the following molecules. What is the...

Question 2

Chemical equations need to be balanced not only in terms of the number of atoms, but also by the charge. In other words, just as there should be the same number of atoms before and after the arrow of an equation, there should be the same charge. What set of coefficients is necessary to balance the following chemical equation? ____ Ce₄+ + ____ Cl⁻ → ____ Ce₃+ + ____ Cl2

Accepted Answer

The answer of Chemical equations need to be balanced not...

Question 3

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn+2 + 2e-
Rxn B: 2 NH₄+ + 2e- → 2 NH₃ + H₂
Which reaction is taking place at the anode?

Accepted Answer

The anode is where oxidation occurs, and in rxn A, Zn is losing electrons (oxidation), making it the reaction that occurs at the anode.

Question 4

The general chemical equation for photosynthesis is shown below. Through this reaction are the oxygens of the water molecules, H₂O, oxidized or reduced? 6 CO₂ + 6H₂O → C₆H₁₂O₆ + 6 O₂

Accepted Answer

The oxygens of the water molecules are oxidized during photosynthesis. In the process, water (H₂O) is split into oxygen (O₂), protons (H⁺), and electrons. The oxygen atoms from water molecules are used to form molecular oxygen (O₂), which is a process of oxidation (loss of electrons).

Question 5

Based on their relative positions in the periodic table, which might you expect to be a stronger oxidizing agent, chlorine or fluorine? Why?

Accepted Answer

Fluorine is a stronger oxidizing agent than chlorine because it is more electronegative due to its greater effective nuclear charge, which attracts electrons more strongly. This makes it more likely to gain electrons in chemical reactions, thus acting as a stronger oxidizing agent.

Question 6

Upon ingestion, grain alcohol, C₂H₆O, is metabolized into acetaldehyde, C2H₄O, which is a toxic substance causing headaches as well as joint pains typical of a "hangover". Is the grain alcohol oxidized or reduced as it transforms into acetaldehyde?

Accepted Answer

The grain alcohol (ethanol, C₂H₆O) is oxidized to form acetaldehyde (C2H₄O). This is evident from the loss of hydrogen atoms in the process, which is a hallmark of oxidation in organic chemistry.

Question 7

Which element is closer to the upper right corner of the periodic table, the one indicated by the lighter colored atoms or the darker colored atoms?

Accepted Answer

The answer of Which element is closer to the upper...

Question 8

Glucose, C₆H₁₂O₆, is a simple sugar that the body metabolizes into two molecules of pyruvic acid, C₃H₄O₃. Is the glucose oxidized or reduced as it transforms into pyruvic acid?

Accepted Answer

The glucose is oxidized because it loses hydrogen (or electrons) as it is converted into pyruvic acid, which is a common characteristic of oxidation reactions in biochemistry.

Question 9

Why is it easier for the body to excrete a polar molecule than it is to excrete a nonpolar molecule? What chemistry does the body use to get rid of molecules it no longer needs?

Accepted Answer

Polar molecules are easier to excrete because they have greater solubility in water. This property allows them to dissolve in bodily fluids and be excreted through urine. Nonpolar molecules, on the other hand, are not soluble in water and tend to be stored in fatty tissues instead of being excreted. The body uses various metabolic processes to get rid of molecules it no longer needs, including digestion, absorption, transportation, and elimination through the urinary and digestive systems.

Question 10

Chemical equations need to be balanced not only in terms of the number of atoms, but also by the charge. In other words, just as there should be the same number of atoms before and after the arrow of an equation, there should be the same charge. What set of coefficients is necessary to balance the following chemical equation? ____ Sn²⁺ + ____ Ag → ____ Sn + _____ Ag⁺

Accepted Answer

The equation balanced in terms of both atoms and charge is: SnS + 2S → Sn + 2Ag⁺. This requires 1 molecule of SnS, 2 molecules of S, 1 molecule of Sn, and 2 ions of Ag⁺, matching option A.

Question 11

In the above diagram, which atom is oxidized, the darker colored atom or the lighter colored atom?

Accepted Answer

The darker colored atom is oxidized because it loses electrons and its oxidation state increases from -1 to 0. The lighter colored atom gains electrons and its oxidation state decreases from +5 to +4, indicating that it is being reduced. Therefore, the darker colored atom is oxidized and the lighter colored atom is reduced.

Question 12

Iron atoms, Fe, are better reducing agents than copper ions, Cu²⁺. In which direction do electrons flow when an iron nail is submerged in a solution of Cu²⁺ ions?

Accepted Answer

Iron atoms are better reducing agents, meaning they more readily lose electrons. When an iron nail is submerged in a solution of copper ions (Cu^2+), electrons flow from the iron (the reducing agent) to the copper ions, reducing them to copper metal.

Question 13

The general chemical equation for photosynthesis is shown below. Through this reaction is the carbon oxidized or reduced? How can you tell? 6 CO₂ + 6H₂O → C₆H₁₂O₆ + 6 O₂

Accepted Answer

The answer of The general chemical equation for photosynthesis is...

Question 14

What correlation might you expect between an element's electronegativity and its ability to behave as an oxidizing agent? How about its ability to behave as a reducing agent?

Accepted Answer

Electronegativity is the tendency of an atom to attract electrons towards itself in a chemical bond. Therefore, atoms with high electronegativity tend to gain electrons easily, making them strong oxidizing agents. On the other hand, these atoms are less likely to lose electrons, making them weak reducing agents.

Question 15

In the above diagram, which atom behaves as the oxidizing agent, the lighter colored atom or the darker colored atom?

Accepted Answer

An oxidizing agent gains electrons and is reduced in a chemical reaction. Without a diagram, the specific behavior of the atoms cannot be determined. However, if the question implies that the lighter colored atom is gaining electrons (a common convention in some diagrams), then it would be acting as the oxidizing agent.

Question 16

What correlation might you expect between an element's ionization energy and its ability to behave as an oxidizing agent? How about its ability to behave as a reducing agent?

Accepted Answer

The answer of What correlation might you expect between an...

Question 17

Clorox is a laundry bleaching agent used to remove stains from white clothes. Suggest why the name begins with Clor- and ends with -ox.

Accepted Answer

The name "Clorox" suggests its chemical composition and function: "Clor-" indicates the presence of chlorine atoms in its active ingredient, and "-ox" refers to its role as a strong oxidizing agent, which is how it bleaches and disinfects.

Question 18

A battery operates by

Accepted Answer

A battery works by converting chemical energy into electrical energy through a process known as electrochemical reaction. This process involves both oxidation (loss of electrons) and reduction (gain of electrons) reactions, which occur simultaneously in the anode and cathode of the battery, respectively. Therefore, option C is the correct choice.

Question 19

When lightning strikes, nitrogen molecules, N2, and oxygen molecules, O₂, in the air react to form nitrates, NO₃-, which come down in the rain to help fertilize the soil. Is this this an example of oxidation or reduction?

Accepted Answer

The nitrogen is oxidized as it gains oxygen to form nitrates, while the oxygen is reduced as it forms bonds with nitrogen.

Question 20

How does an atom's electronegativity relate to its ability to become oxidized?

Accepted Answer

Electronegativity refers to the ability of an atom to attract electrons towards itself. Atoms with higher electronegativity tend to attract electrons more strongly, making them less likely to lose electrons and thus less likely to become oxidized. Oxidation involves the loss of electrons, so atoms that are less inclined to lose electrons (i.e., those with higher electronegativity) have a lower ability to become oxidized.

Quiz 13: Chemical Reactions