A storm has knocked out power to your beach house, and you would like to build a battery from household items to charge your iPhone. You have the following materials. alum in the kitchen, which can be used to make a 1.0 M Al 3+ solution bleach, which is a solution that is approximately a 1.0 M in ClO - aluminum foil, a platinum necklace and bologna, which can be used as a salt bridge (b) What voltage can be generated?

Welcome back everyone. We're told that during the weekend you stayed in your vacation villa in the countryside. When a blackout happened, you desire to create a battery to charge your phone. You brought a liquid foundation with you which can be used to make one point oh moller magnesium two plus solution. You have bathroom cleaners in your villa that can produce a one molar peroxide solution. You also made a salt bridge from the tissue paper soaked in potassium nitrate solution made from makeup primer, determine the voltage that can be produced. Were given our reduction potential of magnesium caddy on equal to negative 2.37 volts and our reduction potential of peroxide equal to 1.78 volts. Our first step is to write out half reactions. So beginning with magnesium caddy on Which Gains two electrons to form solid magnesium. And when we look up in our textbooks, we would see that we have a reduction potential equal to negative 2.37V. And this is actually given in the prompt here as well. And then we have our second half reaction where we have peroxide Which reacts with two moles of protons And two electrons to form liquid water. And according to the prompt, we have a reduction potential equal to 1.78V. Now based on these two reduction potentials. Because we see that this first reduction potential negative 2.37V is more negative. We can confirm that this more negative reduction potential means that magnesium solid is a better reducing agent than liquid water. And so with knowing that magnesium is a better reducing agent, we're going to actually reverse this reaction so that we show an oxidation where now we would have solid magnesium which forms magnesium two plus and releases two electrons. And so we would Ultimately make our reverse reaction be the negative of our original reduction potential, meaning that we would now have negative times a negative, which would give us a positive reduction potential now equal to positive 2.37V. And we can see that because we have electrons on the product side here. This reaction occurs as an oxidation and so that leaves our remaining reaction here with peroxide as our reduction where we can observe that in both of these reactions, we have matching number of electrons. So we can actually straightforwardly add up these two reactions together where we would cancel out the electrons on the product side here and then on the reactant side here and carry down everything that we're left with. So what we're left with for an overall equation is magnesium solid plus peroxide, one mole of peroxide Plus our two moles of protons Yields one mole of Magnesium Catalan Plus one mole of liquid water. And now we just need to calculate our overall cell potential. So we would take the cell potential and add the cell potential of our reduction reaction plus our cell potential of our oxidation. And so that would give us our self potential equal to Our reduction cell potential, which we confirmed is 1.78V Plus our oxidation cell potential, which we've confirmed is positive 2.37V. And this gives us a self potential equal to a total of 4.15V. And now that we know ourself potential for this overall reaction, this would be our voltage that would be produced from the battery that you create during your vacation when there's a blackout. So this would correspond to choice C in the multiple choice. I hope that everything I read was clear. If you have any questions, please leave them down below and I'll see everyone in the next practice video.

Ch.19 - Electrochemistry

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McMurry 8th Edition

Ch.19 - Electrochemistry

Problem 121b

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Chapter 19, Problem 121b

A storm has knocked out power to your beach house, and you would like to build a battery from household items to charge your iPhone. You have the following materials. alum in the kitchen, which can be used to make a 1.0 M Al³⁺ solution bleach, which is a solution that is approximately a 1.0 M in ClO^-aluminum foil, a platinum necklace and bologna, which can be used as a salt bridge (b) What voltage can be generated?

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Identify the half-reactions for the redox process. The aluminum foil can act as the anode, where Al is oxidized to Al^{3+}, and the ClO^- from bleach can act as the cathode, where it is reduced.

Write the oxidation half-reaction: Al \rightarrow Al^{3+} + 3e^-.

Write the reduction half-reaction: ClO^- + 2H_2O + 2e^- \rightarrow Cl^- + 2OH^-.

Use the standard reduction potentials to find the cell potential. Look up the standard reduction potential for each half-reaction: E^\circ_{Al^{3+}/Al} and E^\circ_{ClO^-/Cl^-}.

Calculate the standard cell potential (E^\circ_{cell}) using the formula: E^\circ_{cell} = E^\circ_{cathode} - E^\circ_{anode}.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electrochemistry

Electrochemistry is the branch of chemistry that deals with the relationship between electrical energy and chemical reactions. It involves the study of redox reactions, where oxidation and reduction occur, leading to the generation of electrical energy. Understanding electrochemical cells, including galvanic cells, is essential for determining how to create a battery from available materials.

Electrode Potential

Electrode potential refers to the voltage developed at an electrode due to the chemical reaction occurring at its surface. Each half-reaction in an electrochemical cell has a standard electrode potential, which can be used to calculate the overall cell potential. The difference in electrode potentials between the anode and cathode determines the voltage output of the battery.

Salt Bridge

A salt bridge is a device used in electrochemical cells to maintain electrical neutrality by allowing the flow of ions between the two half-cells. It typically contains a gel or solution of an inert electrolyte, which helps to balance the charge as the redox reactions proceed. In this scenario, using bologna as a salt bridge can facilitate ion movement, crucial for the battery's operation.

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Related Practice

You are on your dream vacation at the beach when a major storm knocks out the power for days. Your cell phone is dead, and you want to make a battery to charge it. You find the following materials in the beach house. blue stone algaecide for pools, which can be used to make a 1.0 M Cu²⁺ solution alum in the kitchen, which can be used to make a 1.0 M Al³⁺ solution aluminum foil, copper wire, and bologna, which can be used as a salt bridge. (b) What voltage can be generated?

A storm has knocked out power to your beach house, and you would like to build a battery from household items to charge your iPhone. You have the following materials. alum in the kitchen, which can be used to make a 1.0 M Al³⁺ solution bleach, which is a solution that is approximately a 1.0 M in ClO^-aluminum foil, a platinum necklace and bologna, which can be used as a salt bridge (a) What are the half-reactions and overall reaction in the battery?

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Textbook Question

A storm has knocked out power to your beach house, and you would like to build a battery from household items to charge your iPhone. You have the following materials. alum in the kitchen, which can be used to make a 1.0 M Al³⁺ solution bleach, which is a solution that is approximately a 1.0 M in ClO^-aluminum foil, a platinum necklace and bologna, which can be used as a salt bridge (d) An iPhone requires 5.0 V for charging. Can this battery charge the phone? Explain.

Open Question

For a lead storage battery: (a) Sketch one cell that shows the anode, cathode, electrolyte, direction of electron and ion flow, and sign of the electrodes. (b) Write the anode, cathode, and overall cell reactions. (c) Calculate the equilibrium constant for the cell reaction (E° = 1.924 V). (d) What is the cell voltage when the cell reaction reaches equilibrium?

Textbook Question

A mercury battery uses the following electrode half-reactions: (b) Calculate ∆G° (in kilojoules) and K at 25 °C for the cell reaction.

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