Recent questions in Chemistry

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A sample of unknown concentration of iron (Fe) is being analyzed using spectrophotometry. The absorbance values obtained from the analysis are: 0.3, 0.6, and 0.9. Using Beer's law, determine the concentration of iron in the sample.

asked Jan 22 in Analytical Chemistry by Sandra59H781 (670 points)

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1 answer 31 views

A sample of nitrogen dioxide is placed in a container at 250°C and 1 atm, where it decomposes according to the following equation: 2NO2(g) ↔ 2NO(g) + O2(g)The initial concentration of NO2 is 0.10 M, and the equilibrium constant (Kc) at this temperature is 4.0 x 10^-3. If the volume of the container is suddenly decreased to one-half of its original volume, causing the pressure to double, what will happen to the amount of NO and O2 present at equilibrium? Calculate the new equilibrium concentrations of NO and O2.

asked Jan 22 in Chemical equilibrium by LatishaMuham (570 points)

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1 answer 34 views

A sample of gas at 25°C and 2 atm is expanded suddenly against a constant external pressure of 1 atm. Calculate the change in entropy of the gas as it expands irreversibly.

asked Jan 22 in Physical Chemistry by AntonKennion (190 points)

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1 answer 67 views

A sample of drinking water from a local source was analyzed for its composition using mass balance calculations. The sample was found to contain 100 mg/L of calcium ions, 50 mg/L of magnesium ions, 20 mg/L of chloride ions, and 10 mg/L of sulfate ions. If the total volume of the sample was measured to be 50 mL, what is the mass of each ion present in the sample?

asked Jan 22 in Analytical Chemistry by ValorieWhitt (430 points)

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1 answer 87 views

A sample of argon gas is contained in a container kept at constant volume. The temperature of the gas is slowly increased by step-wise increments. The energy absorbed by the sample at each increment is recorded, and the average energy of the gas at each temperature is calculated. Using this data, the student is asked to determine the heat capacity of the gas at constant volume and explain why this value only depends on the temperature of the system.

asked Jan 22 in Physical Chemistry by GerardoGall2 (390 points)

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1 answer 48 views

A sample of an unknown inorganic compound weighing 6.25 grams was analyzed to determine its empirical and molecular formulas. After combustion, the sample produced 9.375 grams of carbon dioxide and 3.125 grams of water. What is the empirical and molecular formula of the inorganic compound?

asked Jan 22 in Inorganic Chemistry by FlynnA74878 (390 points)

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1 answer 52 views

A sample of an unknown inorganic compound contains 44.44% magnesium, 22.22% sulfur, and 33.33% oxygen by mass. Determine the empirical formula of the compound. If the molar mass of the compound is 120 g/mol, what is its molecular formula?

asked Jan 22 in Inorganic Chemistry by ElsaLoman15 (430 points)

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1 answer 10 views

A sample of an unknown compound was analyzed using elemental analysis, and the results showed that the compound contains 12.8% hydrogen, 49.2% carbon, and 38.0% oxygen by mass. What is the empirical formula of the compound?

asked Jan 22 in Analytical Chemistry by NidaTimms920 (270 points)

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1 answer 70 views

A sample of an inorganic compound contains 51.28% sodium, 21.44% sulfur, and 27.28% oxygen by mass. Determine the empirical formula of the compound.

asked Jan 22 in Inorganic Chemistry by Nydia80H2789 (350 points)

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1 answer 87 views

A sample of a white powder was analyzed in the laboratory and found to be composed of 40% carbon, 6.67% hydrogen, and 53.33% oxygen by mass. Determine the empirical formula of the compound.

asked Jan 22 in Inorganic Chemistry by LouanneBowle (490 points)

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1 answer 60 views

A sample of a compound was analyzed and found to contain 52.35 % iron, 13.82 % sulfur, and 33.83 % oxygen by mass. Determine the empirical formula of the compound.

asked Jan 22 in Inorganic Chemistry by JacelynWeiss (430 points)

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1 answer 33 views

A sample of a compound contains 28.6% sodium, 46.8% sulfur, and 24.6% oxygen. Determine the empirical formula of this inorganic compound.

asked Jan 22 in Inorganic Chemistry by LenoraRepass (470 points)

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1 answer 68 views

A sample of 55.0 g of ethanol at 25°C is vaporized at its normal boiling point. The enthalpy of vaporization for ethanol is 38.56 kJ/mol. Calculate the amount of heat energy required for this process.

asked Jan 22 in ThermoChemistry by ConnorWatkin (330 points)

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1 answer 10 views

A researcher is working on the desorption of a specific gas from a metal surface. The enthalpy of desorption for this process is -23.4 kJ/mol. If the researcher desorbs 0.75 moles of the gas, how much heat is released (or absorbed)?

asked Jan 22 in ThermoChemistry by LacyWehner92 (310 points)

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1 answer 26 views

A redox reaction is at equilibrium with a standard cell potential of +0.54 V. If the concentration of the oxidizing agent is increased by a factor of 5, what effect will this have on the position of the equilibrium and the cell potential? Assume that the reaction takes place at 25°C.

asked Jan 22 in Chemical equilibrium by PrinceNewsom (70 points)

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1 answer 11 views

A reaction mixture initially contained 0.1 mol/L of reactant A and 0.2 mol/L of reactant B. When a catalyst was added, the rate of conversion of A and B to the product increased significantly. Calculate the new equilibrium concentration of reactant B if the equilibrium constant of the reaction is 0.1 and the initial equilibrium concentration of the product is 0.05 mol/L. Assume that the catalyst does not change the equilibrium constant.

asked Jan 22 in Chemical equilibrium by ChristenaPic (270 points)

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1 answer 11 views

A reaction in a container has an equilibrium constant of K = 5.0 x 10^-3 at a particular temperature. If the volume of the container is suddenly decreased by a factor of 2, what will happen to the concentration of each of the reactants and products at equilibrium? Use the reaction below:2A + B ⇌ 3C + D

asked Jan 22 in Chemical equilibrium by ReganHannam5 (350 points)

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1 answer 10 views

A question for the student to solve could be: If a certain equilibrium reaction is exothermic, and the concentration of reactant A is increased while the concentration of product B is decreased, predict the change in the equilibrium constant value (K) and explain your reasoning by applying Le Chatelier's principle.

asked Jan 22 in Chemical reactions by DorothyGilbe (290 points)

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1 answer 44 views

A piece of zinc metal is placed in a beaker containing an acidic solution, while a copper electrode is also placed in the same solution. The copper electrode is connected to the positive terminal of a voltmeter, while the zinc electrode is connected to the negative terminal of the voltmeter. If the measured potential between the two electrodes is -0.76 V, what is the corrosion potential of the zinc electrode?

asked Jan 22 in ElectroChemistry by MiaTryon261 (390 points)

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1 answer 61 views

A piece of metal with a mass of 15 grams initially at 25°C is placed in 50 mL of water at 80°C. After the metal has reached thermal equilibrium with the water, its temperature is 30°C. Calculate the specific heat capacity of the metal.

asked Jan 22 in ThermoChemistry by JesusJack053 (270 points)

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