Recent questions in ThermoChemistry

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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 79 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 IsabellFrome (2.1k points)

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1 answer 114 views

A chemistry student wants to prepare a solution that contains 25% ethanol (by volume) and the rest is water. The enthalpy of mixing for ethanol and water is -21.2 kJ/mol. How much heat is evolved when the student makes 500 mL of the solution?

asked Jan 22 in ThermoChemistry by MercedesLang (2.2k points)

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1 answer 93 views

A chemistry student wants to mix 50 mL of water at 25°C with 50 mL of ethanol at 25°C to make a solution. The heat of mixing for water and ethanol is -21.2 kJ/mol. Calculate the heat (in kJ) absorbed or released when the two liquids are mixed. (Assume the densities of water and ethanol are approximately 1 g/mL and 0.8 g/mL, respectively.)

asked Jan 22 in ThermoChemistry by NateDicks693 (1.8k points)

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1 answer 88 views

A chemistry student wants to know the specific heat capacity of aluminum. The student has an aluminum block weighing 100 grams at a temperature of 20°C. The student heats the block until its temperature reaches 90°C by adding 500 Joules of heat. What is the specific heat capacity of aluminum?

asked Jan 22 in ThermoChemistry by TiaraFitzgib (2.1k points)

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1 answer 108 views

A chemistry student wants to determine the specific heat capacity of an unknown metal. The student performs a calorimetry experiment and records the following data: - 50 mL of water at 25°C was added to a calorimeter. - The initial temperature of the metal was 100°C. - The final temperature of the metal and water mixture was 30°C. - The mass of the metal was 100 grams.What is the specific heat capacity of the metal?

asked Jan 22 in ThermoChemistry by AustinL82055 (1.8k points)

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1 answer 113 views

A chemistry student wants to determine the specific heat capacity of a metal sample. The student adds 50 g of the metal sample to 200 g of water at 25°C in a calorimeter. The temperature of the water rises from 25°C to 38°C. Assume the specific heat capacity of water is 4.184 J/g°C. What is the specific heat capacity of the metal sample?

asked Jan 22 in ThermoChemistry by VirgilioAbe5 (1.9k points)

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1 answer 120 views

A chemistry student wants to calculate the enthalpy of adsorption for the adsorption of nitrogen gas on a solid adsorbent. The student knows that the initial and final pressures of the nitrogen gas are 1 bar and 0.5 bar, respectively, and the surface area of the adsorbent is 2m^2/g. The student also has data on the temperature and the amount of nitrogen gas adsorbed on the adsorbent. Can you help the student calculate the enthalpy of adsorption?

asked Jan 22 in ThermoChemistry by AlfredLamb10 (2.1k points)

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1 answer 104 views

A chemistry student wants to calculate the enthalpy change (∆H) upon hydrolysis of magnesium chloride (MgCl2). The student knows that the enthalpy of formation (∆Hf) of MgCl2 is -641 kJ/mol and the enthalpy of formation of water (∆Hf) is -286 kJ/mol. The balanced chemical equation for the hydrolysis of magnesium chloride is MgCl2 + 2H2O → Mg(OH)2 + 2HCl. Calculate the enthalpy change (∆H) of this reaction.

asked Jan 22 in ThermoChemistry by KrystleFarth (1.7k points)

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1 answer 68 views

A chemistry student wants to calculate the amount of heat required to melt 15 grams of ice at 0°C. Given that the enthalpy of fusion of ice is 6.01 kJ/mol, what is the total amount of heat required to completely melt the ice?

asked Jan 22 in ThermoChemistry by Camilla86G58 (1.8k points)

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1 answer 84 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 MichelleHall (2.0k points)

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1 answer 42 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 JonasQuj2910 (2.1k points)

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1 answer 117 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 WhitneyCarey (1.8k points)

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1 answer 150 views

A chemistry student needs to determine the enthalpy of desorption for a specific substance. The substance was adsorbed onto activated carbon in a packed bed reactor at 25°C and under a pressure of 4 bar. The adsorption process was carried out until saturation was reached. The packed bed reactor was then heated to 100°C until complete desorption. The pressure was maintained at 4 bar during the entire process. Given the initial mass of the adsorbate and the final mass of the activated carbon, calculate the enthalpy of desorption for the substance.

asked Jan 22 in ThermoChemistry by JannaWales93 (2.0k points)

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1 answer 117 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 HalinaAlderm (1.9k points)

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1 answer 132 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 ChuRosenbaum (2.2k points)

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1 answer 77 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 MargueriteSl (1.9k points)

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1 answer 112 views

A chemistry student needs to calculate the enthalpy of adsorption of ammonia that is adsorbed on silica gel at a temperature of 298 K. The student is provided with the following information: - The partial pressure of ammonia in the gas phase is 0.5 atm- The initial temperature of the clean silica gel is 298 K- The final temperature of the adsorbed ammonia and silica gel mixture is 306 K- The mass of ammonia adsorbed on silica gel is 0.025 grams What is the enthalpy of adsorption of ammonia on silica gel at 298 K, in kJ/mol?

asked Jan 22 in ThermoChemistry by BuckY7205505 (1.7k points)

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1 answer 151 views

A chemistry student needs to calculate the enthalpy of adsorption for NH3 gas onto a silica gel adsorbent. The mass of silica gel used is 5.00g and the initial temperature of the system is 298K. The student also measures the equilibrium pressure of the NH3 gas at 298K to be 0.222atm. To carry out the experiment, the student passes NH3 gas over the silica gel and waits until it reaches equilibrium. The temperature of the system is then measured to be 305K. Using this information, what is the enthalpy of adsorption of NH3 onto the silica gel adsorbent in kJ/mol?

asked Jan 22 in ThermoChemistry by ValeriaStrom (1.7k points)

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1 answer 124 views

A chemistry student is given the following thermochemical equations: Equation 1: H2 (g) + 1/2O2 (g) → H2O(l) ΔH1 = -285.8 kJ/mol Equation 2: C(s) + O2 (g) → CO2 (g) ΔH2 = -393.5 kJ/mol Equation 3: 2H2 (g) + O2 (g) → 2H2O(l) ΔH3 = -571.6 kJ/mol Using Hess's Law, calculate the enthalpy change for the following reaction: C(s) + 2H2 (g) → CH4 (g)

asked Jan 22 in ThermoChemistry by IsraelSeidel (1.3k points)

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