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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 ErmelindaSey (1.8k points)

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1 answer 69 views

Calculate the enthalpy change of the polymerization reaction of ethylene, given that the enthalpy of combustion of ethylene is -1411.1 kJ/mol and that the polymerization of ethylene releases 3.4 kJ/mol.

asked Jan 23 in ThermoChemistry by HalinaAlderm (1.9k points)

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1 answer 146 views

What is the pH of a solution prepared by mixing 25 mL of 0.1 M hydrochloric acid (HCl) with 50 mL of 0.05 M sodium hydroxide (NaOH)?

asked Jan 21 in Inorganic Chemistry by AgnesXyg5256 (2.0k points)

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1 answer 78 views

Calculate the amount of energy required to completely desorb 2 moles of hydrogen molecules from a metal surface if the enthalpy of desorption for each H2 molecule is 436 kJ/mol.

asked Jan 23 in ThermoChemistry by RodrigoHopwo (1.9k points)

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1 answer 73 views

Calculate the enthalpy change for the adsorption of nitrogen gas on the surface of activated charcoal, given that the adsorption pressure is 1 atm at a temperature of 298 K. The quantity of nitrogen gas adsorbed is 0.01 moles per gram of charcoal, and the heat of combustion of the same amount of charcoal is -35.4 kJ/mol.

asked Jan 23 in ThermoChemistry by AdeleStrothe (2.1k points)

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1 answer 74 views

Calculate the corrosion potential of a copper metal electrode in a solution containing 0.1M CuSO4 and 0.5M H2SO4 at 298K, given that the standard electrode potential of the Cu2+/Cu electrode is +0.34V and a hydrogen electrode is used as the reference electrode.

asked Jan 23 in ElectroChemistry by GreggTimperl (2.4k points)

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1 answer 115 views

A chemistry student needs to analyze a sample of a mixture that consists of anionic and cationic species. Using capillary electrophoresis, determine the presence and concentration of each species in the sample. Additionally, suggest a suitable buffer system and optimize the electrophoresis conditions for efficient separation and detection of the species.

asked Jan 22 in Analytical Chemistry by AntonioDaven (1.7k points)

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1 answer 107 views

A student is given a sample of an inorganic compound that contains only carbon and hydrogen. The sample has a mass of 0.500 g and, upon combustion, produces 1.442 g of carbon dioxide and 0.589 g of water. Determine the empirical formula of the compound.

asked Jan 22 in Inorganic Chemistry by CorneliusU11 (1.7k points)

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1 answer 73 views

Calculate the enthalpy change (ΔH) for the following reaction: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)using the following bond enthalpies (in kJ/mol):NH3(g): N-H = 391, N ≡ N = 941O2(g): O=O = 498NO(g): N=O = 628H2O(g): O-H = 463

asked Jan 23 in Inorganic Chemistry by MarkusPaquet (1.7k points)

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1 answer 59 views

Calculate the heat of neutralization for the reaction of 50 mL of 2.0 M hydrochloric acid and 50 mL of 2.0 M sodium hydroxide. The specific heat capacity of the solution is 4.18 J/g°C and the temperature change is 10°C.

asked Jan 23 in ThermoChemistry by JackQ7308746 (2.0k points)

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1 answer 106 views

A student needs to determine the mass of silver that can be deposited on a silver electrode using a current of 2.5 A for 3 hours in a solution containing 0.2 M silver ions. What is the mass of silver deposited on the electrode? (Assuming 100% current efficiency and atomic weight of silver is 107.9 g/mol)

asked Jan 22 in ElectroChemistry by MuhammadNuna (2.1k points)

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1 answer 75 views

Calculate the bond length between two oxygen atoms in an O2 molecule, given that the O-O bond energy is 498 kJ/mol and the reduced mass of the system is 15.9994 g/mol.

asked Jan 23 in Chemical bonding by AdeleStrothe (2.1k points)

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1 answer 70 views

Calculate the enthalpy change for the hydrolysis of 2 moles of sucrose (C12H22O11) into glucose (C6H12O6) and fructose (C6H12O6) given the following information:- Enthalpy of formation of glucose = -1273 kJ/mol- Enthalpy of formation of fructose = -1260 kJ/mol- Enthalpy of formation of sucrose = -2226 kJ/mol

asked Jan 23 in ThermoChemistry by MagdaMeares (1.8k points)

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1 answer 59 views

Calculate the heat of hydration when 10.0 g of calcium chloride (CaCl2) dissolves in 100 g of water at 25°C. The enthalpy of solution for calcium chloride is -81.5 kJ/mol.

asked Jan 23 in ThermoChemistry by EloisaLeavit (1.5k points)

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1 answer 77 views

Calculate the amount of heat required to sublime 50 grams of dry ice (CO2) at -78.5°C given that the heat of sublimation for CO2 is 25.2 kJ/mol.

asked Jan 23 in ThermoChemistry by JonasHaller8 (1.5k points)

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1 answer 77 views

Calculate the amount of heat required to raise the temperature of 50 grams of water from 25°C to 85°C, given the specific heat of water is 4.184 J/g°C.

asked Jan 23 in ThermoChemistry by AgnesXyg5256 (2.0k points)

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1 answer 115 views

A chemistry student is given a sample of an unknown compound and is asked to determine its molecular formula and possible functional groups using mass spectrometry. The mass spectrum of the compound shows a molecular ion peak at m/z 158 and three intense fragmentation peaks at m/z 132, 104, and 77. Using this information, determine the molecular formula and possible functional groups of the unknown compound.

asked Jan 22 in Analytical Chemistry by GlenSchramm (1.7k points)

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1 answer 75 views

Calculate the bond enthalpy for the carbon-oxygen bond in carbon dioxide (CO2) using the following data:- Bond enthalpy of carbon-oxygen double bond = 799 kJ/mol- Bond enthalpy of carbon-oxygen single bond = 358 kJ/molShow all calculations and units.

asked Jan 23 in Chemical bonding by ElviaM111599 (1.4k points)

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1 answer 114 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 AleidaSeifer (1.7k points)

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1 answer 102 views

A student wants to synthesize a polymer using the monomer vinyl chloride. The reaction is exothermic and produces a polymer with an average molecular weight of 50,000 g/mol. The enthalpy change of polymerization for this reaction is -121.8 kJ/mol. How much heat is liberated during the polymerization of 1 mol of vinyl chloride?

asked Jan 22 in ThermoChemistry by CorneliusChi (1.6k points)

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