Recent questions in Chemistry

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1 answer 78 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 MaddisonFarw (510 points)

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1 answer 71 views

A chemistry student wants to perform a reaction that produces carbon dioxide gas. If the student has 500 grams of calcium carbonate and an excess of hydrochloric acid, how many liters of carbon dioxide gas can be produced at Standard Temperature and Pressure (STP)? (Assume the reaction goes to completion)

asked Jan 22 in Chemical reactions by LacyBastyan (550 points)

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1 answer 57 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 Jannette93D8 (510 points)

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1 answer 45 views

A chemistry student wants to measure the zeta potential of a colloidal solution. The student has chosen the appropriate instrument, but needs to determine the optimal pH range for the solution in order to obtain accurate and meaningful results. What is the recommended method to determine the optimal pH range for measuring the zeta potential of a colloidal solution, and how can the student ensure accurate and reliable measurements using this method?

asked Jan 22 in Surface Chemistry by LesleyStyers (670 points)

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1 answer 59 views

A chemistry student wants to measure the surface tension of a liquid but does not have access to a tensiometer. How can the student measure the surface tension using simple materials found in a chemistry lab?

asked Jan 22 in Surface Chemistry by TomHatley066 (770 points)

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1 answer 37 views

A chemistry student wants to measure the rate of a chemical reaction. The reaction involves the reaction between zinc and hydrochloric acid. The student weighed out 0.5 grams of zinc and mixed it with 50 mL of 0.5 M hydrochloric acid. The student measured the time it took for the reaction to complete and found it took 3 minutes to produce all the hydrogen gas. Calculate the rate of the reaction in grams of zinc per minute.

asked Jan 22 in Chemical reactions by RaymonLamar7 (770 points)

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1 answer 78 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 Breanna4436 (550 points)

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1 answer 56 views

A chemistry student wants to know the equilibrium constant for the reaction between nitrogen and hydrogen to produce ammonia. If the initial concentration of nitrogen is 0.2 moles/L, the initial concentration of hydrogen is 0.1 moles/L, and the equilibrium concentration of ammonia is 0.3 moles/L, what is the equilibrium constant for this reaction?

asked Jan 22 in Chemical reactions by ToddPamphlet (590 points)

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1 answer 57 views

A chemistry student wants to know how the equilibrium of a reaction will be affected by an increase in temperature. The reaction studied is N2(g) + 3H2(g) ↔ 2NH3(g) and has an equilibrium constant (Kc) of 3.5 x 10^-5 at a certain temperature. If the temperature is increased, what will happen to the concentration of NH3 at equilibrium?

asked Jan 22 in Chemical reactions by JaredHerzog0 (270 points)

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1 answer 56 views

A chemistry student wants to know how the concentration of reactants and products affects the equilibrium constant of a chemical reaction. They decide to investigate the reaction between nitrogen gas and oxygen gas to form nitrogen dioxide gas, and the equilibrium constant Kc for this reaction. What is the relationship between the concentration of reactants and products and the equilibrium constant for this reaction, and how can this be explained by Le Chatelier's principle?

asked Jan 22 in Physical Chemistry by CharoletteFa (350 points)

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1 answer 82 views

A chemistry student wants to investigate the effect of changing the volume on the equilibrium position for the reaction between nitrogen and hydrogen gas to form ammonia. If the student initially has 1 mole of nitrogen gas and 3 moles of hydrogen gas in a 2-liter container at equilibrium, and then decreases the volume to 1 liter while maintaining the same temperature, what will happen to the equilibrium concentration of ammonia in moles per liter?

asked Jan 22 in Chemical equilibrium by SilkeRede903 (410 points)

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1 answer 42 views

A chemistry student wants to investigate the adsorption of a certain gas onto a solid surface. The student conducts an experiment and obtains the following data for different pressures of the gas:| Pressure (p) / atm | Quantity adsorbed (q) / g ||---|---|| 0.1 | 0.12 || 0.2 | 0.21 || 0.3 | 0.29 || 0.4 | 0.36 || 0.5 | 0.41 || 0.6 | 0.49 |Using the Langmuir adsorption isotherm, the student wants to determine the maximum amount of the gas that can be adsorbed onto the surface (q_max) and the rate constant for the adsorption process (k_ads). What are the values of q_max and k_ads for this gas-surface sys

asked Jan 22 in Surface Chemistry by PerryTolmie (390 points)

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1 answer 46 views

A chemistry student wants to investigate the adsorption behavior of a gas on a solid surface. Using the Langmuir adsorption isotherm, determine the maximum adsorption capacity of the surface and the equilibrium constant, if the surface area of the solid is 10 cm$^2$ and the gas pressure is varied from 0.1 to 1 bar at a constant temperature of 298 K.

asked Jan 22 in Surface Chemistry by Leo425114985 (250 points)

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1 answer 8 views

A chemistry student wants to investigate the activation energy for a reaction between hydrogen and chlorine gases. The student measures the initial and final temperatures of the reaction mixture, and the rate of gas evolution. Based on this information, the student wants to calculate the activation energy of the reaction using the Arrhenius equation. What steps should the student follow to determine the activation energy of the reaction?

asked Jan 22 in Chemical reactions by ThaoCrews506 (210 points)

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1 answer 57 views

A chemistry student wants to find the concentration of a hydrochloric acid (HCl) solution. To do this, the student performs a titration experiment with a sodium hydroxide (NaOH) solution of known concentration. The student adds 25 mL of the HCl solution to a flask with an indicator, and then slowly adds the NaOH solution until the indicator changes color. It was found that it took 18.2 mL of the 0.1 M NaOH solution to reach the endpoint. What is the concentration of the HCl solution?

asked Jan 22 in Chemical reactions by ChadwickIeve (270 points)

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1 answer 63 views

A chemistry student wants to find out the effect on the equilibrium position when the volume of a reaction mixture is changed. They have an equilibrium mixture of hydrogen and iodine gases forming hydrogen iodide gas according to the equation:$$H_2 (g) + I_2 (g) \leftrightharpoons 2HI (g)$$At 298 K, the equilibrium constant for this reaction is 54.3. Initially, the reaction mixture contains 0.5 moles of hydrogen gas, 0.5 moles of iodine gas, and 0 moles of hydrogen iodide gas in a container of volume 2L. If the volume is reduced to 1L while maintaining the temperature at 298 K, what wi

asked Jan 22 in Chemical equilibrium by MichelineClo (490 points)

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1 answer 55 views

A chemistry student wants to determine the surface area of a porous material using gas adsorption. The student has access to a BET specific surface area analyzer and pure nitrogen gas. What is the surface area of the porous material if the adsorption isotherm shows a monolayer formation at the partial pressure of nitrogen adsorption around 0.1?

asked Jan 22 in Surface Chemistry by KeeshaMcLeay (510 points)

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1 answer 41 views

A chemistry student wants to determine the surface area of a metal oxide sample using the Langmuir adsorption isotherm. The student collects adsorption data at different pressures and determines the amount of gas adsorbed on the surface. The Langmuir isotherm equation used is y = Kx / (1 + Kx), where y is the fractional surface coverage, x is the pressure of the gas, and K is a constant related to the adsorption energy. The student obtains the following data:Pressure (atm) | Fractional surface coverage-------------|---------------------------

asked Jan 22 in Surface Chemistry by NellMtg43094 (430 points)

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1 answer 53 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 EsperanzaAch (570 points)

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1 answer 35 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 ByronHedges2 (290 points)

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