Recent questions in Chemistry

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1 answer 65 views

A chemistry lab has 20 grams of magnesium and 30 grams of hydrochloric acid. What is the exact amount (in grams) of magnesium chloride that will be produced in a complete reaction between magnesium and hydrochloric acid?

asked Jan 22 in Chemical reactions by VickeyBatema (1.9k points)

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1 answer 86 views

A chemistry experiment was conducted to determine the rate constant for the reaction between hydrogen peroxide and iodide ion in acidic medium. The initial concentrations of hydrogen peroxide and iodide ion were 0.2 M and 0.1 M respectively. The reaction was carried out at 25°C and the time taken for the completion of the reaction was 60 seconds. Based on these data, what is the rate constant for the reaction?

asked Jan 22 in Chemical kinetics by SenaidaDelac (1.8k points)

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1 answer 98 views

A chemistry experiment involves burning a sample of propane gas, C3H8, and measuring the heat released. If 2.00 grams of propane is burned completely to produce CO2(g) and H2O(l), and the heat of combustion is found to be -2044 kJ/mol, what is the heat released in kJ when 2.00 grams of propane is burned?

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

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1 answer 76 views

A chemist wants to produce 5 grams of ammonia (NH3) gas through the reaction of nitrogen gas (N2) and hydrogen gas (H2). What mass of hydrogen gas is needed, assuming excess nitrogen gas is provided? (Hint: balance the chemical equation and use stoichiometry to calculate the required mass)

asked Jan 22 in Chemical reactions by StanGjo3033 (1.9k points)

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1 answer 86 views

A chemist performed a reaction that was supposed to produce 25 grams of the desired product. However, upon measuring the amount of product produced, it was found that only 18 grams were obtained. Calculate the percent yield of the reaction.

asked Jan 22 in Chemical reactions by HermelindaYm (2.3k points)

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1 answer 89 views

A chemist mixes 0.1 mol of hydrogen (H2) with 0.2 mol of nitrogen (N2) in a 2 L flask at 400°C. The reaction H2(g) + N2(g) ⇌ 2NH3(g) establishes equilibrium. Calculate the equilibrium concentrations of hydrogen, nitrogen, and ammonia if the Kc value of the reaction at this temperature is 1.5 x 10^-2.

asked Jan 22 in Chemical equilibrium by CarmaC633252 (1.7k points)

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1 answer 82 views

A chemist is attempting to electroplate copper onto a steel surface using a copper sulfate solution. The standard reduction potential for this reaction is -0.34 V, but the scientist is only seeing a voltage of -0.53 V. Calculate the overpotential for this electrochemical reaction.

asked Jan 22 in ElectroChemistry by MeaganCramp (1.8k points)

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1 answer 86 views

A chemist has a sample of an unknown compound with a mass of 5.00 g. After analyzing the sample, the following results were obtained: 0.50 g of oxygen, 1.25 g of carbon, and 3.25 g of hydrogen. Calculate the molecular formula of the unknown compound using mass balance calculations.

asked Jan 22 in Analytical Chemistry by KreogMoore5 (6.4k points)

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1 answer 71 views

A chemist analyzed a sample of unknown substance and found that it contains 55% carbon, 9.17% of hydrogen and the rest of the mass is oxygen. What is the percentage by mass of oxygen in the sample?

asked Jan 22 in Analytical Chemistry by GracieGainfo (2.2k points)

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1 answer 57 views

A chemical reaction was carried out at constant temperature and pressure. The initial concentration of the reactants and products were known. After a certain amount of time, the concentration of the reactants and products were measured. Using non-equilibrium thermodynamics, calculate the magnitude and sign of the entropy change of the system during the reaction.

asked Jan 22 in Physical Chemistry by KrystleFarth (1.7k points)

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1 answer 82 views

A chemical reaction of N2O4(g) ⇌ 2NO2(g) is established in a closed vessel at a certain temperature. The initial concentration of N2O4 is 0.1M. At equilibrium, the concentration of NO2 is found to be 0.6M. Calculate the equilibrium concentration of N2O4.

asked Jan 22 in Chemical equilibrium by RebekahH3016 (1.9k points)

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1 answer 74 views

A chemical reaction is taking place where nitrogen gas and hydrogen gas are being combined to form ammonia gas. According to Le Chatelier's principle, how would increasing the pressure of the system affect the yield of ammonia gas? Provide a scientific explanation for your answer.

asked Jan 22 in Chemical reactions by DaleHaveman (2.1k points)

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1 answer 97 views

A chemical plant needs to separate a mixture of benzene and toluene using a distillation column. The feed contains 40% benzene and 60% toluene. Design a distillation column to achieve a distillate with at least 90% purity of benzene. Provide the reflux ratio and the number of theoretical trays required to meet the purity specification. Assume an operating pressure of 1 atm and th

asked Jan 22 in Chemical engineering by MarcyLowrie (2.3k points)

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1 answer 61 views

A chemical mixture containing 30% ethanol and 70% water needs to be separated using a distillation column. The feed rate is 1000 kg/hr and the desired purity for both products is 99%. The distillation column has 20 theoretical trays, and the reflux ratio is 2.5. Determine the number of trays required to achieve the desired purity for both products.

asked Jan 22 in Chemical engineering by TBHMelaine51 (2.2k points)

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1 answer 40 views

A chemical engineering firm has been tasked with designing a chemical reactor for the synthesis of ammonia gas from nitrogen and hydrogen gases. The plant requires a production of at least 1000 kg/h of ammonia gas, and the reactor should operate at a pressure of 200 atm and a temperature of 400°C. The student should determine the optimal size and design of the reactor by considering the reaction kinetics, thermodynamics, and fluid dynamics principles. The student should also select appropriate catalysts and determine the flow rate of the reactants required to achieve the desired production rate.

asked Jan 22 in Chemical engineering by LeroyBothwel (1.9k points)

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1 answer 92 views

A chemical engineering company has a mixture of ethanol and water with a concentration of 30% ethanol to separate using a distillation column. The company needs to obtain a concentration of 80% ethanol in the distillate at a reflux ratio of 3. Calculate the number of theoretical plates required in the column for the separation, assuming no vapor or liquid bypass, and that the minimum vapor velocity is maintained.

asked Jan 22 in Chemical engineering by SvenJonathan (1.9k points)

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1 answer 72 views

A chemical engineer wants to separate a mixture of ethanol and methanol using a distillation column. The feed to the column contains 30% ethanol and 70% methanol by mole. The engineer wants to obtain a distillate with 80% ethanol and a bottoms product containing no more than 1% ethanol. Determine the number of trays required in the distillation column to achieve this separation. Consider only equilibrium stages and assume that the feed is saturated liquid at its boiling point. The operating pressure of the column is 1 atm.

asked Jan 22 in Chemical engineering by FerminRosale (1.5k points)

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1 answer 70 views

A chemical engineer needs to separate a mixture of ethanol and water using a distillation column. The feed to the column has 30 mol% ethanol and 70 mol% water, and the desired distillate composition is 95 mol% ethanol. The feed rate is 100 kmol/hour and the reflux ratio is 2. Calculate the number of theoretical trays required in the column to achieve the desired distillate composition.

asked Jan 22 in Chemical engineering by Francisca504 (1.9k points)

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1 answer 77 views

A chemical engineer needs to design a distillation column for the separation of a mixture containing ethanol (boiling point of 78.4°C) and water. The desired composition of the distillate is a minimum of 90% ethanol. What is the minimum number of theoretical trays needed in the column to achieve this composition, given that the feed contains 40% ethanol and the reflux ratio is 1.5?

asked Jan 22 in Chemical engineering by Precious09K0 (2.0k points)

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1 answer 68 views

A certain polymerization reaction has a ΔH°rxn of -250 kJ/mol. If you need to make 500 grams of the polymer, how much energy in kilojoules will be released or absorbed during the reaction?

asked Jan 22 in ThermoChemistry by StacyS111358 (2.3k points)

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