Recent questions in Chemistry

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1 answer 43 views

A chemistry student needs to determine the standard enthalpy change for the formation of NH3(g) from its constituent elements, using Hess's Law calculations. The student is given the following information:ΔHf°(NH3) = -46 kJ/molΔHf°(N2) = 0 kJ/molΔHf°(H2) = 0 kJ/molΔH298°(N2H4) = 95 kJ/molΔHf°(N2H4) = 50 kJ/mol2NH3(g) + N2H4(l) → 3N2(g) + 4H2(g)What is the value of ΔHf° for NH3, based on the above data?

asked Jan 22 in ThermoChemistry by HassieCooch5 (490 points)

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1 answer 32 views

A chemistry student needs to determine the specific heat capacity of a metal block. The student has the following information: the mass of the block is 75 g and its initial temperature is 25°C. The student heats the block to 100°C, and calculates that it absorbed 1500 J of heat during this process. What is the specific heat capacity of the metal block?

asked Jan 22 in ThermoChemistry by MarinaWsq125 (450 points)

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1 answer 59 views

A chemistry student needs to determine the rate law for the reaction between hydrogen peroxide and iodide ion in the presence of an acid catalyst. Using experimental data, what is the order of the reaction with respect to hydrogen peroxide, iodide ion, and acid? Write the rate law equation for this reaction.

asked Jan 22 in Chemical kinetics by HeatherMacca (370 points)

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1 answer 56 views

A chemistry student needs to determine the rate constant for the reaction between hydrochloric acid and sodium thiosulfate. If the initial concentration of hydrochloric acid is 0.1 M, the initial concentration of sodium thiosulfate is 0.05 M, and the initial rate of the reaction is 8.7 x 10^-5 mol/L.s, what is the rate constant for this reaction?

asked Jan 22 in Chemical kinetics by XLCLynwood47 (450 points)

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1 answer 39 views

A chemistry student needs to determine the rate constant (k) and the initial rate (vo) of an enzymatic reaction that follows Michaelis-Menten kinetics. The reaction involves the conversion of substrate A to product B in the presence of an enzyme that is inhibited by a competitive inhibitor. The student should also calculate the inhibition constant (Ki) of the inhibitor and determine the type of inhibition (competitive, non-competitive or uncompetitive).

asked Jan 22 in BioChemistry by ShaunTulloch (550 points)

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1 answer 70 views

A chemistry student needs to determine the precipitate formed when 50 mL of 0.2 M silver nitrate solution is mixed with 75 mL of 0.1 M potassium chloride solution. What is the mass of the precipitate formed and what is the percent yield of the reaction?

asked Jan 22 in Chemical reactions by Rajatoto88 (350 points)

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1 answer 9 views

A chemistry student needs to determine the pH of an unknown solution using a pH meter. The student is given the following equipment: pH meter, reference electrode, and a container for the solution. The student should describe the steps needed to measure the pH of the solution and explain the significance of the obtained pH value.

asked Jan 22 in Analytical Chemistry by KarolynElg36 (450 points)

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1 answer 57 views

A chemistry student needs to determine the pH of a solution using a pH meter. The student has to prepare a buffer solution of pH 7.0 using 0.1M acetic acid and 0.1M sodium acetate. The student is then required to measure the pH of the prepared buffer solution using a pH meter and record the observations. Finally, the student has to compare the pH value obtained by the pH meter with the calculated pH value of the prepared buffer solution and explain any deviations observed.

asked Jan 22 in Analytical Chemistry by GradyK025281 (410 points)

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1 answer 60 views

A chemistry student needs to determine the percentage of iron (Fe) present in a given iron ore sample using gravimetric analysis. The student is provided with the mass of the iron ore sample and a standardized solution of potassium dichromate (K2Cr2O7) to use for the analysis. What is the percentage of iron (Fe) in the given iron ore sample?

asked Jan 22 in Analytical Chemistry by MahaliaCampb (570 points)

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1 answer 39 views

A chemistry student needs to determine the percentage of calcium carbonate (CaCO3) present in a mixture of calcium carbonate and calcium phosphate. The student has the following information: A 1.00-gram sample of the mixture was dissolved and reacted with excess hydrochloric acid (HCl), producing 0.236 grams of carbon dioxide (CO2) gas. The balanced chemical equation for the reaction is: CaCO3 + 2HCl → CaCl2 + CO2 + H2O. The student also knows that the molecular weight of CaCO3 is 100.09 g/mol and that of Ca3(PO4)2 is 310.18 g/mol. What is the percentage of calcium carbonate in the mixture?

asked Jan 22 in Analytical Chemistry by ArdisRolston (350 points)

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1 answer 61 views

A chemistry student needs to determine the percent composition of nitrogen (N) in a sample of an unknown organic compound. Using elemental analysis, the student determines the mass of the sample to be 0.254 g and the mass of the products after combustion to be 0.727 g of CO2 and 0.298 g of H2O. What is the percent composition of nitrogen in the sample?

asked Jan 22 in Analytical Chemistry by PhilipMcKeon (250 points)

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1 answer 60 views

A chemistry student needs to determine the percent by mass of magnesium (Mg) in a sample of limestone. The student has access to 5 grams of the sample and is provided with the following information: the sample is comprised of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3); the atomic masses of the elements are: Ca = 40.08 g/mol, C = 12.01 g/mol, O = 16.00 g/mol, and Mg = 24.31 g/mol; and the sample contains a total of 3.06 grams of carbon (C). Calculate the percentage by mass of magnesium in the limestone sample using mass balance calculations.

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

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1 answer 55 views

A chemistry student needs to determine the oxidation state changes of the atoms and identify the oxidizing and reducing agents in the following reaction: C2H5OH + 2 MnO4- → 2 CH3COOH + 2 MnO2 + 4 OH-

asked Jan 22 in Organic Chemistry by ChristinaLeF (310 points)

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1 answer 52 views

A chemistry student needs to determine the new equilibrium concentration of a complex ion, if the temperature is increased by 10°C from the initial temperature of 25°C, and the equilibrium constant for the reaction is 0.056. The initial concentration of the reactants are: [Fe3+] = 0.025 M, [SCN-] = 0.015 M, and [FeSCN2+] = 0.007 M.

asked Jan 22 in Chemical equilibrium by Carmon10Y870 (350 points)

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1 answer 35 views

A chemistry student needs to determine the molar mass of aluminum chloride (AlCl3). What is the molar mass of aluminum chloride?

asked Jan 22 in Inorganic Chemistry by CarrolTomkin (310 points)

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1 answer 81 views

A chemistry student needs to determine the major product(s) formed from the reaction between 1-bromo-3-methylcyclohexane and sodium ethoxide in ethanol solvent with a heat source. What are the major products formed and explain the mechanism of the reaction?

asked Jan 22 in Organic Chemistry by MadgeGreene4 (850 points)

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1 answer 57 views

A chemistry student needs to determine the Langmuir constant and maximum adsorption capacity of a metal oxide nanoparticle using the Langmuir adsorption isotherm equation from experimental data obtained at different concentrations of a given adsorbate in the water. Determine the Langmuir equation parameters and plot the experimental data and the Langmuir model using a graph. Finally, interpret the results in terms of the adsorption behavior of metal oxide nanoparticle towards the selected adsorbate.

asked Jan 22 in Surface Chemistry by AguedaMuniz6 (580 points)

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1 answer 68 views

A chemistry student needs to determine the equilibrium constant (Kc) for the reaction: N2(g) + 3H2(g) ⇌ 2NH3(g)At a certain temperature, 0.2 mole of nitrogen gas (N2), 0.3 mole of hydrogen gas (H2), and 0.4 mole of ammonia gas (NH3) were placed in a 1 L container. Using these initial concentrations, what is the equilibrium constant (Kc) for the reaction?

asked Jan 22 in Chemical equilibrium by BTUDanielle4 (470 points)

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1 answer 62 views

A chemistry student needs to determine the equilibrium concentrations of reactants and products for the following reaction:2 NOCl (g) ⇌ 2 NO (g) + Cl2 (g)The initial concentration of NOCl is 0.50 M and the equilibrium constant, Kc = 4.68 x 10^-3. What are the equilibrium concentrations of NO and Cl2?

asked Jan 22 in Chemical equilibrium by MicahReidy99 (350 points)

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1 answer 70 views

A chemistry student needs to determine the enthalpy of oxidation of magnesium. For this, they need to conduct an experiment in which they react 1 gram of magnesium metal with excess hydrochloric acid of 2 moles concentration. They need to measure the temperature change that occurs during the reaction, which they will use to calculate the enthalpy of oxidation of magnesium. What is the enthalpy of oxidation of magnesium according to the student's experiment?

asked Jan 22 in ThermoChemistry by ChetChadwick (370 points)

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