Recent questions without an upvoted answer

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A student needs to determine the concentration of a sulfuric acid solution using a sodium hydroxide solution of known concentration. The student performs a titration and records that it took 27.5 milliliters of the sodium hydroxide solution to neutralize 25 milliliters of the sulfuric acid solution. What is the concentration (in moles per liter) of the sulfuric acid solution?

asked Jan 22 in Chemical reactions by DorieEverson (2.0k points)

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1 answer 78 views

A student needs to determine the change in enthalpy (ΔH) for the reaction between methane (CH4) and oxygen (O2) to form carbon dioxide (CO2) and water (H2O) at a temperature of 25°C and a pressure of 1 atm. The initial concentrations of CH4 and O2 are both 0.1 M, and the final concentrations of CO2 and H2O are both 0.05 M. What is the change in enthalpy for this reaction at the given conditions?

asked Jan 22 in Physical Chemistry by AveryJoris20 (2.0k points)

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1 answer 86 views

A student needs to determine the amount of copper present in a sample of brass using coulometry. If the sample is dissolved in acid and subjected to coulometric analysis using a standard silver electrode, what is the concentration of copper (in ppm) in the brass sample?

asked Jan 22 in Analytical Chemistry by MaybellHoffm (2.2k points)

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1 answer 42 views

A student needs to determine the activation energy for the electrochemical reaction between zinc and copper sulfate using the Arrhenius equation. The student has experimental data that includes the rate constants and temperatures at which the reaction was performed. Using the experimental data, the student needs to calculate the activation energy for the reaction and explain the significance of this value in terms of the reaction kinetics.

asked Jan 22 in ElectroChemistry by EdwinLindell (1.9k points)

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1 answer 91 views

A student needs to determine the activation energy for an electrochemical reaction involving the oxidation of Zinc using a voltage of 1.85V, a current of 0.25A and a temperature of 25°C. Given that the standard potential for this reaction at 25°C is -0.76V, what is the activation energy of the reaction?

asked Jan 22 in ElectroChemistry by KassieStarns (2.3k points)

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1 answer 98 views

A student needs to calculate the Tafel slopes for the anodic and cathodic reactions from a given set of experimental data obtained during an electrochemical experiment. The experiment involves the corrosion of iron in a solution with a pH of 3.5. The anodic and cathodic current densities were measured at various applied potentials ranging from -700 mV vs SHE to -400 mV vs SHE. The student needs to plot a Tafel plot for each reaction and calculate their corresponding Tafel slopes. Based on the obtained results, the student needs to explain the corrosion mechanism of iron in the given acidic solution.

asked Jan 22 in ElectroChemistry by BrentonMcQua (1.7k points)

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1 answer 89 views

A student needs to calculate the standard potential of a electrochemical cell formed by a zinc electrode and a silver electrode. The concentration of Zn2+ ions in the zinc half-cell is 1.0 M and the concentration of Ag+ ions in the silver half-cell is 0.1 M. The measured potential of the cell is 1.95 V. What is the standard potential of the cell?

asked Jan 22 in Physical Chemistry by LarhondaKeel (1.6k points)

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1 answer 140 views

A student needs to calculate the standard enthalpy of formation of magnesium oxide, MgO, using Hess's Law. The student has access to the following reactions and their corresponding enthalpy changes:1. Mg(s) + 1/2O2(g) → MgO(s) ΔH = -601.8 kJ/mol2. Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) ΔH = -450.7 kJ/mol3. H2(g) + 1/2O2(g) → H2O(l) ΔH = -285.8 kJ/molWhat is the standard enthalpy of formation of MgO from its elements?

asked Jan 22 in ThermoChemistry by Marlene31P52 (2.5k points)

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1 answer 131 views

A student needs to calculate the standard enthalpy change of combustion for propane using Hess's Law. They have the following information: C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l) ΔH° = -2220 kJ/mol 2H2(g) + O2(g) → 2H2O(l) ΔH° = -484 kJ/mol 3C(s) + 2H2(g) → C3H8(g) ΔH° = +51 kJ/mol What is the standard enthalpy change of combustion for propane?

asked Jan 22 in ThermoChemistry by ReinaldoBull (2.2k points)

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1 answer 145 views

A student needs to calculate the standard cell potential for the following reaction at 25°C:Zn (s) + Fe2+ (aq) → Zn2+ (aq) + Fe (s)Given:- Standard reduction potentials: Eº(Zn2+/Zn) = -0.76 V and Eº(Fe2+/Fe) = -0.44 V- Concentration of Fe2+ = 0.1 M and concentration of Zn2+ = 1.0 MWhat is the value of the standard cell potential for this reaction?

asked Jan 22 in Physical Chemistry by NadiaN491716 (2.1k points)

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1 answer 130 views

A student needs to calculate the resistance of an electrochemical cell that has a concentration of 0.1 M for both copper(II) and zinc(II) ions, using an electrochemical sensor that measures 2.5 volts for the cell. Calculate the resistance of the electrochemical cell at room temperature, given that the Faraday constant is 96485 C/mol and the gas constant is 8.314 J/(mol·K).

asked Jan 22 in ElectroChemistry by OtisMacGilli (2.0k points)

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1 answer 93 views

A student needs to calculate the maximum electrical work that can be obtained from an electrochemical cell of standard hydrogen electrode (SHE) potential -0.76 V and a zinc electrode potential of -0.46 V, when 0.5 moles of zinc metal is oxidized to form zinc ions at 25 °C. Assume that the Faraday constant is 96,485 Coulombs per mole of electrons and the gas constant is 8.314 J/mole.K.

asked Jan 22 in ElectroChemistry by TrenaSee705 (1.7k points)

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1 answer 147 views

A student needs to calculate the heat of mixing for a 50 mL solution containing 0.1 M HCl and 0.1 M NaOH. The temperature of the solution is 25°C and the density is 1 g/mL. The enthalpy of neutralization for HCl and NaOH is -57.3 kJ/mol. Determine the heat of mixing for the solution.

asked Jan 22 in ThermoChemistry by VictorinaWoz (1.9k points)

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1 answer 96 views

A student needs to calculate the Faraday constant for the reduction of copper ions in a solution using a current of 2.5 amperes for 5 minutes. If the mass of copper deposited on the cathode was 0.3 grams, what is the value of the Faraday constant?

asked Jan 22 in ElectroChemistry by MerissaGxv8 (1.7k points)

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1 answer 137 views

A student needs to calculate the enthalpy change for a chemical reaction given the enthalpies of formation of the reactants and products. The specific problem is: Calculate the enthalpy change for the reaction:CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)Given the following enthalpies of formation:ΔHf(CH4) = -74.8 kJ/molΔHf(CO2) = -393.5 kJ/molΔHf(H2O) = -285.8 kJ/mol

asked Jan 22 in Chemical reactions by ChristenaGra (1.6k points)

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1 answer 91 views

A student needs to calculate the efficiency of an electrochemical cell that has a potential difference of 1.5 volts and a current of 0.5 amperes passing through it, with the help of Faraday's Law. If the electrode reaction produces chlorine gas with a Faraday efficiency of 79%, and the overall voltage efficiency of the cell is 85%, what is the efficiency of the electrochemical cell?

asked Jan 22 in ElectroChemistry by Jaqueline50I (2.0k points)

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1 answer 87 views

A student needs to calculate the efficiency of a voltaic cell that has a standard potential difference of 0.78 V and produces a current of 2.5 A. The cell is operated for 8 hours and consumes a total of 2400 Coulombs of charge. What is the efficiency of this electrochemical cell?

asked Jan 22 in ElectroChemistry by EdwardoO6191 (2.5k points)

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1 answer 142 views

A student needs to calculate the current density (in Amperes per square meter) of a copper electrode (Area = 10 cm²) in an electrochemical cell where the half-cell reaction is Cu²⁺ + 2e⁻ → Cu and the cell voltage is 1.1 V. The concentration of Cu²⁺ in the cell is 0.1 M.

asked Jan 22 in ElectroChemistry by KristinCoghl (1.7k points)

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1 answer 80 views

A student needs to calculate the current density (in A/m^2) in an electrochemical cell with a cross-sectional area of 0.01 m^2 and a current of 0.5 A passing through it. The half-cell reactions are as follows:Anode: Zn(s) -> Zn2+(aq) + 2e^-Cathode: Cu2+(aq) + 2e^- -> Cu(s)The concentrations of Zn2+ and Cu2+ ions in the solutions are 0.1 M and 0.01 M, respectively. The temperature of the cell is 298 K. Calculate the current density.

asked Jan 22 in ElectroChemistry by AudreaV25265 (2.0k points)

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1 answer 95 views

A student needs to calculate the activation energy for a reaction that takes place at an electrode with a current density of 2.5 mA/cm² at a temperature of 25°C. The reaction has a transfer coefficient of 0.5 and a standard rate constant of 2.0 × 10⁻⁶ cm/s. The student has access to the necessary thermodynamic data for the reaction. What is the activation energy for this electrochemical reaction?

asked Jan 22 in ElectroChemistry by DeenaTrundle (2.2k points)

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