Check-In & Practice Questions

Question

Watch: “Asking Questions about Redox Reactions” Portfolio clip and record three points of interest.
Q1) Consider this reaction. Think about what you learned in the video, then make a list of five questions that you could pose to determine whether or not this is a redox reaction.
1.

2.

3.

4.

5.

Describe the rusting process.

Practice Part 1 - Plan Your Own Investigation

STEP 1: Write a scientific question that you want to answer during your investigation.

STEP 2: Review the partial list of suggested materials. Why do you think these materials were suggested? What effects will they have on rusting?

STEP 3: Identify the control and experimental groups you will have in your steel wool investigation. You may have as many experimental groups as you desire to test different conditions.

STEP 4: Develop a step-by-step procedure to conduct your experiment. In your procedure, describe the data you will collect and how often you will take readings.

PORTFOLIO DAY 2

Check-In & Practice Questions
Q1) Write a prediction for each group in your steel wool experiment. Explain your reasoning for each prediction.

Q2) Explain how you will use the data you collect from your steel wool investigation to determine whether a redox reaction occurred.

Practice Part 2 - Conduct the Experiment

Did any of the materials used in the experiment prevent the steel wool from reacting with water and oxygen? If so, how?

Evaluate the chemical reaction for rusting of iron. Which chemical species is oxidized? Which is reduced?



. Record your results in this table:

Solution
Results
1.

2.

3.

4.

5.


PORTFOLIO DAY 2

Check-In & Practice Questions

Q1) Refer to the chemical equation of rusting of iron and the image of the iron oxide molecule. Draw a model that shows electron transfer when iron and oxygen chemically react to form rust.

Q2) Use your model to explain why rusting is a redox reaction.

Practice Part 3 - Evaluate the Results
As you evaluate the data you collected from your steel wool experiment, you may notice that rusting occurred in some of your test groups but not in others. Perhaps you noticed that some groups showed signs of rusting much earlier than others. As you evaluate your data from each group, consider what factors are needed for rust to occur, and determine whether those factors in each of your test groups.

Summarize the results of your experiment. Record a complete paragraph (5 sentences) here.

What factors affected the rate of rusting in your experiment? List at least 3 in complete sentences.

Reflection
What did you learn from your investigation?

How could the results of investigations like the one you did be used?

and also explain everything and every answer you gave in this test and why

Answer 1

Check-In & Practice Questions

Points of Interest from Video

1. Electron Transfer: The video described how redox reactions are characterized by the transfer of electrons between species.
2. Oxidation and Reduction: It clearly explained the distinction between oxidation (loss of electrons) and reduction (gain of electrons).
3. Indicators of Redox Reactions: It discussed various indicators that can signal whether a reaction is a redox reaction, like changes in oxidation states.

Q1: Questions to Determine if a Reaction is a Redox Reaction

1. What are the oxidation states of the elements in the reactants and products?
2. Is there a transfer of electrons between species during the reaction?
3. Which element is being oxidized and which is being reduced?
4. Are there any observable changes in the appearance of the substances involved in the reaction?
5. What evidence supports that the reaction involves electron transfer?

Rusting Process Description

Rusting is an electrochemical process that occurs when iron reacts with oxygen in the presence of water or moisture. Initially, iron (Fe) is oxidized to ferrous ions (Fe²⁺), while oxygen is reduced to hydroxide ions (OH⁻) in an aqueous environment. The ferrous ions can further react with hydroxides to form ferric oxide (Fe₂O₃·nH₂O), commonly known as rust. This process is accelerated by the presence of salts and acids, which can increase conductivity in the water, leading to quicker corrosion.

---

Practice Part 1 - Plan Your Own Investigation

STEP 1: Scientific Question

How do varying amounts of water affect the rate of rusting in steel wool?

STEP 2: Suggested Materials Review

The suggested materials likely include steel wool, water, different metal ions (like salt), and varying containers. These materials were chosen because they provide essential components for rusting: steel wool (iron source), water (catalyst), and salt (can enhance ionic conductivity and corrosion rate).

STEP 3: Identify Control and Experimental Groups

• Control Group: Steel wool kept dry, with no water added.
• Experimental Groups: Steel wool exposed to various amounts of water (e.g., 10 mL, 20 mL, 50 mL), and another group exposed to saltwater (e.g., water mixed with salt).

STEP 4: Step-by-Step Procedure

1. Prepare five containers, labeling each one with the amount of water it will hold (dry, 10 mL, 20 mL, 50 mL, saltwater).
2. Place an equal amount of steel wool in each container.
3. For saltwater, mix a specific amount of salt in the 50 mL of water.
4. Leave the containers at room temperature for one week.
5. After 24 hours, and each day thereafter, observe and record the presence of rust or any color changes.
6. Measure the amount of rust visually, using a scale from 0 (no rust) to 5 (severe rust).

---

PORTFOLIO DAY 2

Q1: Predictions for Each Group

• Dry Group: I predict no rust will form because there is no moisture.
• 10 mL Water Group: Rust will form slowly due to minimal water.
• 20 mL Water Group: There will be moderate rust formation, being enough moisture to support rusting without excess.
• 50 mL Water Group: Significant rust formation expected due to excess moisture.
• Saltwater Group: I predict the most rust will form because salt enhances conductivity, accelerating the corrosion process.

Q2: Data Collection for Redox Reaction

I will compare the extent of rust (color change and texture) in each group. If electron transfer is present, I expect to see oxidation of iron (steel wool) and reduction of oxygen in all groups with water, as demonstrated by rust formation.

---

Practice Part 2 - Conduct the Experiment

Did Materials Prevent Reaction?

If any materials were coated or sealed, they could prevent the steel wool from reacting with water and oxygen by creating a barrier that inhibits moisture from reaching the iron surface.

Evaluate the Rusting Reaction

In the rusting process, iron (Fe) is oxidized to iron ions (Fe²⁺), losing electrons (oxidation). Oxygen (O₂) in the presence of water is reduced as it gains electrons (reduction) to form hydroxide ions (OH⁻).

---

Results Table

| Solution | Results | |------------------|----------------------------------------------------| | 1. Dry Group | No rust formation. | | 2. 10 mL Water | Slight rust formation (score 2). | | 3. 20 mL Water | Moderate rust (score 3). | | 4. 50 mL Water | Significant rust (score 4). | | 5. Saltwater | Severe rust (score 5). |

---

PORTFOLIO DAY 2

Q1: Draw Model of Electron Transfer

[This requires a diagram, which may show iron atoms losing electrons and oxygen atoms gaining those electrons.]

Q2: Why Rusting is a Redox Reaction

Rusting is a redox reaction because iron loses electrons, undergoing oxidation, while oxygen in the presence of moisture gains electrons, undergoing reduction. This transfer of electrons is the fundamental basis of redox reactions.

---

Practice Part 3 - Evaluate the Results

Summary of Results

Throughout the experiment, the rate of rusting varied significantly across different groups. The control group without water showed no signs of rust, while minimal rust appeared in the 10 mL group. The 20 mL group exhibited a moderate rust level, and the 50 mL group showed a high level of rust formation. The saltwater group had the most severe rust, confirming that higher moisture and the presence of salts enhance the rusting process.

Factors Affecting Rate of Rusting

1. Amount of Water: More water allows for greater electron transfer, facilitating rust formation.
2. Presence of Salt: Salt increases conductivity, accelerating the rusting process due to enhanced ionic exchanges.
3. Air Exposure: Increased surface area exposed to oxygen promotes oxidation, leading to increased rusting.

Reflection

I learned that varying environmental conditions, such as moisture and salt presence, significantly impact the rusting rate of iron. The importance of these variables can inform practical applications, such as improving the durability of iron materials in different settings.

Applications of Results

Results from investigations like this can inform industries about the best practices for preserving iron materials, particularly in construction and automotive sectors where corrosion can lead to structural failure. It can also help in developing anti-corrosive coatings and treatments.