Recent questions in Chemistry

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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 AveryCoughli (450 points)

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1 answer 39 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 WillWilber35 (510 points)

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1 answer 81 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 BrittneyN44 (350 points)

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1 answer 40 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 DarcyStevens (510 points)

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1 answer 54 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 Kami22A8614 (490 points)

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1 answer 81 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 LindseyTulk (330 points)

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1 answer 48 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 StewartLivin (490 points)

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1 answer 54 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 IrwinDeBoos5 (610 points)

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1 answer 50 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 IrvinLeichha (410 points)

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1 answer 52 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 TCMKayla0289 (350 points)

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1 answer 60 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 DevonGreeves (390 points)

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1 answer 41 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 LinoLadd0317 (400 points)

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1 answer 78 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 Christiane98 (390 points)

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1 answer 48 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 ShellyGiron1 (410 points)

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1 answer 59 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 ShaniGrondin (630 points)

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1 answer 56 views

A student needs to analyze an unknown sample to determine the percent composition of three compounds present in it. The student conducts a combustion reaction to determine the percent of carbon and hydrogen in the sample. The remaining residue is then dissolved in water and the solution is titrated with a standardized silver nitrate solution to determine the chloride ion concentration in the sample. Calculate the percent composition of each compound in the unknown sample using mass balance calculations.

asked Jan 22 in Analytical Chemistry by TrentAdam35 (470 points)

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1 answer 71 views

A student mixed 25.0 grams of sodium hydroxide with excess hydrochloric acid. If the theoretical yield of sodium chloride is 34.0 grams, what is the percent yield of the reaction?

asked Jan 22 in Chemical reactions by FrankieBerge (210 points)

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1 answer 59 views

A student mixed 10 grams of iron and 15 grams of oxygen to produce iron oxide. What is the limiting reactant and what is the mass of the iron oxide produced? (Assume all reactions are complete)

asked Jan 22 in Chemical reactions by DaisyStow838 (990 points)

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1 answer 50 views

A student mixed 0.1 M solution of NH3 and 0.1 M solution of NH4Cl to form a buffer solution of NH3/NH4+. If the initial pH of the solution is 9.25, what will be the final pH of the solution when 0.01 moles of HCl is added? (Assume the volume of the solution is constant).

asked Jan 22 in Chemical equilibrium by AlexandraCru (510 points)

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1 answer 75 views

A student measures the current in a galvanic cell with a standard potential of 1.10 V, using a Zinc electrode and a Copper electrode. The student recorded the current as 0.50 A. What is the rate of the electrochemical reaction occurring in the cell?

asked Jan 22 in ElectroChemistry by StephanyWurs (470 points)

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