Recent questions in Chemistry

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A chemistry student needs to determine the dipole moment of a molecule that has three atoms arranged in a linear fashion, where the central atom is a carbon atom and the other two atoms are chlorine atoms. The student must also explain the factors that contribute to the dipole moment of the molecule.

asked Jan 22 in Chemical bonding by NellMtg43094 (970 points)

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1 answer 60 views

A chemistry student needs to determine the conditions required for a liquid mixture of water and ethanol to boil at a temperature of exactly 80°C. What is the minimum percentage of ethanol needed in the mixture and at what pressure should it be boiled in order to achieve this specific boiling point?

asked Jan 22 in Physical Chemistry by Cortney07C58 (290 points)

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1 answer 91 views

A chemistry student needs to determine the conditions at which a pure substance will change from solid to liquid phase. The substance in question has a melting point of 120 °C and a heat of fusion of 35 kJ/mol. How much heat is required to melt 100 grams of the substance at its melting point? And, what is the temperature at which the substance will start to solidify if the ambient pressure is 1 atm and the substance has cooled from its liquid phase at 150 °C to its solid phase?

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

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1 answer 91 views

A chemistry student needs to determine the concentration of silver nitrate (AgNO3) in a given sample from the following information:- A 10 mL sample of 0.1 M sodium chloride (NaCl) was mixed with excess silver nitrate.- The resulting precipitate was filtered, washed, and dried. The mass of the precipitate was found to be 0.212 g.- The molar mass of AgNO3 is 169.87 g/mol.What is the concentration of AgNO3 in the original sample?

asked Jan 22 in Analytical Chemistry by MariamLandal (310 points)

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1 answer 86 views

A chemistry student needs to determine the concentration of NaOH in a 250 mL solution. They know that 10 mL of the solution was titrated with 0.1 M HCl solution, which required 8.5 mL of the HCl solution to be fully neutralized. Based on this information, what is the concentration of NaOH in the solution?

asked Jan 22 in Analytical Chemistry by Alfonzo8121 (730 points)

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1 answer 57 views

A chemistry student needs to determine the concentration of iron (III) ions in a water sample using spectrophotometry. The water sample contains an unknown amount of iron (III) ions that need to be quantified with a high degree of accuracy. The student has access to a spectrophotometer and an iron (III) ion standard solution to be used as a reference for the analysis. What is the concentration of iron (III) ions in the water sample?

asked Jan 22 in Analytical Chemistry by ZacharyFairb (290 points)

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1 answer 90 views

A chemistry student needs to determine the concentration of a sulfuric acid solution by titrating 25.0 mL of the acid with 0.1000 M sodium hydroxide. The reaction between the two substances is H2SO4 + 2NaOH → Na2SO4 + 2H2O. If it takes 35.0 mL of the sodium hydroxide solution to fully neutralize the sulfuric acid, what is the concentration of the sulfuric acid solution in moles per liter (M)?

asked Jan 22 in Chemical reactions by FranTober475 (230 points)

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1 answer 81 views

A chemistry student needs to determine the concentration of a copper sulfate solution by using mass balance calculations. The student knows that a 100 mL sample of the solution at an unknown concentration was diluted to 500 mL, and then 50 mL of the diluted solution was titrated with a standardized sodium thiosulfate solution. The titre value was 10.0 mL. The student needs to determine the concentration of the copper sulfate solution in terms of grams per liter (g/L).

asked Jan 22 in Analytical Chemistry by Luke37258313 (310 points)

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1 answer 55 views

A chemistry student needs to determine the concentration of a certain analyte in a water sample using colorimetry. The student has access to a spectrophotometer and a standard calibration curve. What is the concentration of the analyte in the water sample, given its absorbance value in the spectrophotometer and the calibration curve data?

asked Jan 22 in Analytical Chemistry by MarieRitchar (290 points)

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1 answer 91 views

A chemistry student needs to determine the composition of a sample that contains an unknown mixture of sodium chloride (NaCl) and potassium chloride (KCl). The student weighs 2.00 g of the mixture and dissolves it in water to obtain a solution. The student then precipitates the chloride ions from the solution with excess silver nitrate (AgNO3) to obtain 6.50 g of silver chloride (AgCl). Using mass balance calculations, determine the mass and percentage composition of the sodium chloride and potassium chloride in the mixture.

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

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1 answer 61 views

A chemistry student needs to determine how the equilibrium constant (Kc) will change when the volume of the container is increased by a factor of 3 for the following reaction at a certain temperature:2NO2(g) ⇌ N2O4(g)

asked Jan 22 in Chemical equilibrium by RefugiaGoffa (210 points)

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1 answer 66 views

A chemistry student needs to determine how the equilibrium concentration of products and reactants change when the temperature is increased in the reaction: 2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g) Given the initial concentrations of 0.15 M SO2, 0.025 M O2, and 0 M SO3, and a temperature increase of 50°C, calculate the new equilibrium concentration of each compound using Le Chatelier's Principle.

asked Jan 22 in Chemical reactions by GuadalupeDan (390 points)

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1 answer 76 views

A chemistry student needs to calculate the standard enthalpy change for the combustion reaction of methane gas (CH4) at 298 K and 1 atm pressure. The equation for the reaction is:CH4(g) + 2O2(g) --> CO2(g) + 2H2O(l)Given the following standard enthalpies of formation at 298 K:ΔHf(CO2) = -393.5 kJ/molΔHf(H2O) = -285.8 kJ/molΔHf(CH4) = -74.8 kJ/molCalculate ΔHrxn, the standard enthalpy change for the combustion reaction of methane gas.

asked Jan 22 in Chemical thermodynamics by ClairePresto (230 points)

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1 answer 102 views

A chemistry student needs to calculate the standard enthalpy change for the combustion reaction of methane (CH4) to produce carbon dioxide (CO2) and water (H2O) at 298 K. The student is given the following information: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ΔH°rxn = -890.4 kJ/molThe enthalpy of formation of CH4(g) and H2O(l) are -74.8 kJ/mol and -285.8 kJ/mol, respectively. Using this data, what is the standard enthalpy change for the combustion reaction of methane (CH4) to produce carbon dioxide (CO2) and water (H2O) at 298 K?

asked Jan 22 in Chemical thermodynamics by MorrisDoming (290 points)

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1 answer 87 views

A chemistry student needs to calculate the rate constant for the following reaction: 2 H2(g) + O2(g) --> 2 H2O(g) The initial concentration of H2 is 0.45 M and the initial concentration of O2 is 0.20 M. The reaction rate is measured to be 0.75 M/s. Calculate the rate constant for the reaction.

asked Jan 22 in Chemical kinetics by RoseScn6045 (350 points)

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1 answer 80 views

A chemistry student needs to calculate the rate constant (k) for the following first-order reaction based on the given data: The half-life of the reaction is 20 seconds when the initial concentration of reactant is 0.2M. What is the rate constant of the reaction?

asked Jan 22 in Chemical kinetics by BlairCoulsto (490 points)

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1 answer 76 views

A chemistry student needs to calculate the new value of the ionization constant (Ka) of a weak acid when the temperature is raised from 25°C to 45°C, given that the initial value of Ka is 1.8 x 10^-5 at 25°C and the enthalpy of ionization (ΔHion) is 50.2 kJ/mol.

asked Jan 22 in Chemical equilibrium by MOTHelene86 (590 points)

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1 answer 85 views

A chemistry student needs to calculate the heat required to raise the temperature of 25.0 g of water from 25°C to 60°C, given that the specific heat capacity of water is 4.18 J/g°C.

asked Jan 22 in ThermoChemistry by KristiAinsli (450 points)

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1 answer 101 views

A chemistry student needs to calculate the heat of sublimation for iodine given that its enthalpy of fusion is 15.52 kJ/mol and its enthalpy of vaporization is 41.57 kJ/mol. The molar mass of iodine is 126.90 g/mol. What is the heat of sublimation for iodine in kJ/mol?

asked Jan 22 in ThermoChemistry by DZGDeclan47 (270 points)

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1 answer 57 views

A chemistry student needs to calculate the heat of hydration for the reaction between anhydrous magnesium chloride (MgCl2) and water (H2O) using the following data: the enthalpy change for the dissolution of anhydrous magnesium chloride in water is -63.3 kJ/mol, and the enthalpy change for the hydration of magnesium ions (Mg2+) and chloride ions (Cl-) is -192 kJ/mol and -131 kJ/mol, respectively. Calculate the overall heat of hydration (in kJ/mol) for the reaction: MgCl2(s) + 6H2O(l) → MgCl2.6H2O(s)

asked Jan 22 in ThermoChemistry by PhilipMcKeon (450 points)

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