Recent questions in Chemistry

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1 answer 45 views

A chemistry student wants to determine the rate constant for the reaction: 2NO(g) + Cl2(g) → 2NOCl(g) They measure the concentrations of all the reactants and products at different times and obtain the following data:Time (s) | [NO] (M) | [Cl2] (M) | [NOCl] (M):--: | :--: | :--: | :--:0 | 0.100 | 0.200 | 0.00010 | 0.080 | 0.180 | 0.04020 | 0.064 | 0.160 | 0.06430 | 0.051 | 0.140 | 0.08140 | 0.041 | 0.120 | 0.089What is the rate constant (k) for this reaction?

asked Jan 22 in Chemical kinetics by PDLCarmella8 (330 points)

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1 answer 8 views

A chemistry student wants to determine the percentage of ethanol in a sample of wine. The student takes a 50 mL aliquot of the wine, dries it, and finds the weight of the residual solids to be 0.325 g. The student then distills the rest of the wine, evaporates the distillate to dryness, and finds the weight of the residue to be 2.324 g. Using mass balance calculations, what is the percentage of ethanol in the wine sample?

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

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1 answer 56 views

A chemistry student wants to determine the percent composition of calcium oxide in a given sample of limestone. The student does an experiment and obtains the mass of the limestone sample, the mass of carbon dioxide evolved upon heating the limestone, and the mass of calcium oxide left behind. Using mass balance calculations, determine the percent composition of calcium oxide in the limestone sample.

asked Jan 22 in Analytical Chemistry by TresaCole198 (530 points)

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1 answer 75 views

A chemistry student wants to determine the Faraday constant (F) by electroplating copper on a platinum electrode using a current of 2.0 A for 10 minutes. Calculate the amount of copper deposited and use this information to determine the value of the Faraday constant.

asked Jan 22 in ElectroChemistry by RBFSuzette64 (430 points)

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1 answer 70 views

A chemistry student wants to determine the enthalpy change of a chemical reaction. They have 25 g of sodium hydroxide and want to mix it with 50 mL of 1.0 M hydrochloric acid. What is the maximum temperature change they can expect to see, assuming constant pressure and perfect heat transfer, and what is the enthalpy change of the reaction?

asked Jan 22 in Physical Chemistry by MarylouSoder (390 points)

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1 answer 43 views

A chemistry student wants to determine the effect of temperature on the ionization constant (Ka) of a weak acid. The initial Ka of the acid is 1.32 × 10^-6 at 25°C. If the temperature is increased to 35°C, calculate the new value of Ka for the weak acid.

asked Jan 22 in Chemical equilibrium by LeiaMagana86 (370 points)

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1 answer 87 views

A chemistry student wants to determine the effect of adding more reactant or product on the equilibrium position of a chemical reaction. The student has a 0.50 M solution of N2O4 and NO2 at equilibrium at 25°C, with the equation N2O4(g) <--> 2NO2(g). If the student adds more N2O4 to the reaction mixture, what will happen to the equilibrium concentration of NO2? Will it increase, decrease or stay the same? Justify your answer with a chemical equation and relevant calculations.

asked Jan 22 in Chemical equilibrium by MiaWelker055 (190 points)

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1 answer 57 views

A chemistry student wants to determine the effect of adding a buffer to a solution containing acetic acid (CH3COOH) and its conjugate base (CH3COO-), which is in equilibrium with its ionized form (H+ and CH3COO-). The initial concentration of acetic acid is 0.2 M and the pH of the solution is 4.5. If the student adds a buffer solution containing equal amounts of acetic acid and sodium acetate (NaCH3COO), what will be the new pH of the solution and the extent of shift in equilibrium position?

asked Jan 22 in Chemical equilibrium by CassieEdmist (250 points)

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1 answer 86 views

A chemistry student wants to determine the effect of adding a buffer solution on the equilibrium position of an acetic acid-sodium acetate reaction. The initial concentrations of acetic acid and sodium acetate are both 0.1 M and the pH of the solution is 4. Calculate the new concentrations of acetic acid, acetate ion, and hydrogen ion after adding a buffer solution containing 0.2 M acetic acid and 0.2 M sodium acetate. What is the new pH of the solution?

asked Jan 22 in Chemical equilibrium by ChadwickIeve (330 points)

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1 answer 88 views

A chemistry student wants to determine the concentration of copper(II) ions in a solution using electrochemical methods. The student prepares a copper electrode and a reference electrode, and sets up a cell with the copper electrode immersed in the solution and the reference electrode in the salt bridge. The standard cell potential is measured to be +0.34 V. If the student knows that the reduction of copper(II) to copper occurs at the copper electrode, what is the concentration of copper(II) ions in the solution?

asked Jan 22 in ElectroChemistry by AmeliaHmelni (350 points)

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1 answer 59 views

A chemistry student wants to determine the concentration of a solution containing iron (III) ions. Using colorimetry, they measure the absorbance of the solution at a specific wavelength and plot a calibration curve with solutions of known iron (III) ion concentration. The student then measures the absorbance of their unknown solution at the same wavelength and uses the calibration curve to determine the concentration of iron (III) ions in the sample. What is the concentration of iron (III) ions in the unknown solution, in units of moles per liter?

asked Jan 22 in Analytical Chemistry by TameraWoodal (490 points)

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1 answer 62 views

A chemistry student wants to determine the bond enthalpy of hydrogen gas (H2). They have access to an experimental setup which can be used to measure the enthalpy change of a chemical reaction. How can the student determine the bond enthalpy of H2 using this setup?

asked Jan 22 in Chemical bonding by Ivy28L91405 (450 points)

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1 answer 47 views

A chemistry student wants to determine the boiling point of a solution of 25 g of glucose in 500 mL of water. Calculate the boiling point of the solution if the boiling point constant of water is 0.512 °C/m and assume an ideal solution.

asked Jan 22 in Physical Chemistry by Zelma07O9922 (370 points)

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1 answer 72 views

A chemistry student wants to determine the amount of iron present in a sample of orange juice. The student takes a 50 mL sample of orange juice and reacts it with excess potassium dichromate in acidic solution. After the reaction, the remaining potassium dichromate requires 12.75 mL of a 0.015 M ferrous ammonium sulfate solution to complete the reaction. What is the mass of iron present in the sample of orange juice?

asked Jan 22 in Analytical Chemistry by ZoraMarrero (230 points)

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1 answer 53 views

A chemistry student wants to design an electrochemical cell that produces a voltage of at least 1.5 volts. The available electrodes are copper and aluminum. Using Faraday's law, calculate the mass of copper needed to produce the required voltage if aluminum is used as the other electrode. The specific gravity of copper is 8.96 g/cm³, and the standard reduction potential of copper and aluminum are -0.34 V and -1.66 V, respectively.

asked Jan 22 in Physical Chemistry by BelenWaite80 (590 points)

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1 answer 69 views

A chemistry student wants to create a chemical reaction that produces exactly 25 grams of water. How many grams of hydrogen and oxygen would need to react to create this amount of water?

asked Jan 22 in Chemical reactions by RobbySpahn63 (430 points)

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1 answer 66 views

A chemistry student wants to create a buffer solution with a pH of 7.2 using acetic acid and sodium acetate. The student has calculated that they need 0.1 moles of each component to make a 250 mL buffer solution. However, the student accidentally added 0.02 moles of hydrochloric acid to the buffer solution. Calculate the new pH of the buffer solution and explain if the addition of the hydrochloric acid has shifted the equilibrium position of the reaction towards the acid or the base.

asked Jan 22 in Chemical equilibrium by AshleighMilf (770 points)

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1 answer 78 views

A chemistry student wants to calculate the pH of a solution formed by mixing 100 mL of 0.1 M HCl with 200 mL of 0.05 M NaOH. What is the pH of the resulting solution?

asked Jan 22 in Inorganic Chemistry by Hortense02O4 (390 points)

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1 answer 73 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 LorrineClant (450 points)

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1 answer 62 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 JamieTrethow (330 points)

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