Recent questions in Chemistry

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A solution containing 0.5 M of iron(III) ions and 0.5 M of thiocyanate ions is allowed to reach equilibrium. If the equilibrium constant of the formation of the FeSCN2+ complex ion is 3.0 x 10^3, calculate the concentration of FeSCN2+ complex ion at equilibrium when the initial concentration of thiocyanate ions is doubled.

asked Jan 22 in Chemical equilibrium by BoydHaynes98 (1.9k points)

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1 answer 86 views

A solution containing 0.1 M acetic acid and 0.1 M sodium acetate has a pH of 4.5. If 0.02 moles of hydrochloric acid is added to the solution, what will be the pH of the solution after equilibrium is reached? (Given pKa of acetic acid = 4.76)

asked Jan 22 in Chemical equilibrium by RoderickKyle (2.4k points)

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1 answer 15 views

A small metal block is placed in a beaker containing boiling water. The block initially weighs 50 grams and its temperature is 25°C. After 5 minutes, its weight is 49 grams and its temperature is 80°C. Determine the entropy change of the metal block during this process assuming it to be irreversible.

asked Jan 22 in Physical Chemistry by DelorasGaise (1.9k points)

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A sealed vessel contains a mixture of nitrogen dioxide and dinitrogen tetraoxide gases in equilibrium. If the volume of the container is increased, would the equilibrium shift towards more or less NO2? Calculate the new equilibrium constant at the new volume assuming the pressure and temperature remain constant.

asked Jan 22 in Chemical equilibrium by KreogMoore5 (6.4k points)

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1 answer 37 views

A sample problem for a chemistry student to solve from the subtopic Calculating the effect of changing the temperature on the equilibrium constant could be: What would be the new equilibrium constant (Kc) for the reaction 2NOCl (g) ↔ 2NO (g) + Cl2 (g) at 400 K, if the initial equilibrium constant at 300 K is 2.50 x 10^-3? Given that the enthalpy change of the reaction (∆H) is -91.84 kJ/mol and the entropy change of the reaction (∆S) is -188.8 J/mol K.

asked Jan 22 in Chemical equilibrium by WalterC19362 (2.4k points)

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1 answer 52 views

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 LavadaKissne (2.4k points)

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1 answer 35 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 MarcellaMack (1.7k points)

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1 answer 38 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 SommerBartos (1.8k points)

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1 answer 83 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 HughNewquist (2.3k points)

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1 answer 99 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 MarianCocket (2.0k points)

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1 answer 58 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 IolaHolly818 (2.0k points)

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1 answer 73 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 DeloresKuhn6 (2.1k points)

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1 answer 34 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 HermineOverb (2.1k points)

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1 answer 118 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 YVMCinda4278 (2.3k points)

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1 answer 104 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 BettyWalsh4 (2.0k points)

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1 answer 110 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 OliviaMilton (2.0k points)

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1 answer 36 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 ErmelindaSey (1.8k points)

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1 answer 87 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 CamillePiazz (1.8k points)

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1 answer 38 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 AbbieGladden (2.1k points)

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1 answer 30 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 73351052550 (1.9k points)

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