Recent questions in Chemistry

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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 KerrieTillma (390 points)

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1 answer 68 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 DerekAmess50 (430 points)

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1 answer 65 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 AleciaBevan0 (450 points)

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1 answer 77 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 ConnorHoller (290 points)

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1 answer 72 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 LatoyaDechai (390 points)

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1 answer 61 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 ZCXMirta8905 (350 points)

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1 answer 45 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 MillieMartin (670 points)

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1 answer 8 views

A chemistry student wants to buffer a solution with a pH of 4.5. The student adds 0.1 mol of a weak acid buffer to 0.1 mol of a conjugate base. Taking the pKa value of the buffer into consideration, determine how much stronger an acid in the same buffer system would need to be added to the solution to shift the pH from 4.5 to 4.0, assuming temperature and pressure are constant.

asked Jan 22 in Chemical equilibrium by YolandaBeard (310 points)

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1 answer 75 views

A chemistry student wants to analyze a sample of wastewater from a local factory. They want to know the concentration of the pollutants from the wastewater before releasing it into the environment. The sample is collected in a 500 mL container. After performing the required tests, the student determines that the total dissolved solids (TDS) in the sample are 750 mg/L, and the concentration of NaCl in the sample is 150 mg/L. Calculate the mass of TDS and NaCl in the sample.

asked Jan 22 in Analytical Chemistry by EdwardClayto (390 points)

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1 answer 56 views

A chemistry student synthesized 25 grams of aspirin theoretically, but only obtained 20 grams practically in the lab. Calculate the percent yield of aspirin.

asked Jan 22 in Chemical reactions by MohammedBris (470 points)

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1 answer 8 views

A chemistry student performed a reaction that produced 2.0 grams of product. The theoretical yield for this reaction is 2.5 grams. Calculate the percent yield for this reaction.

asked Jan 22 in Chemical reactions by IngridMarcha (390 points)

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1 answer 66 views

A chemistry student needs to quantify the amount of iron (II) ions in a sample using colorimetry. The sample was prepared by dissolving a known mass of iron (II) sulfate in water, and the solution was diluted to a known volume. The student needs to determine the concentration of iron (II) ions in the original solution by measuring the absorbance of the sample using a colorimeter, and then using calibration curves to convert the absorbance to concentration. The student also needs to calculate the percentage error of the experiment and suggest ways to improve the accuracy of the results.

asked Jan 22 in Analytical Chemistry by MeaganClubbe (200 points)

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1 answer 71 views

A chemistry student needs to prepare a buffer solution with a pH of 7.2 using acetic acid (CH3COOH) and sodium acetate (CH3COONa). The student has 100 mL of 0.1 M acetic acid and 100 mL of 0.1 M sodium acetate. What volume of each solution do they need to mix to prepare the desired buffer solution with a total volume of 500 mL?

asked Jan 22 in Chemical reactions by BryceLeone68 (650 points)

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1 answer 59 views

A chemistry student needs to prepare a buffer solution with a pH of 5.2 using acetic acid (CH3COOH) and sodium acetate (NaC2H3O2). The student has 10 mL of 0.15 M acetic acid and 15 mL of 0.20 M sodium acetate. What volume of water should the student add to make the desired buffer solution?

asked Jan 22 in Chemical reactions by ShaunFeez63 (270 points)

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1 answer 87 views

A chemistry student needs to prepare a buffer solution of pH 5.0 using acetic acid and acetate ions. If the student has 0.3 M acetic acid and 0.2 M acetate ions, what volume of acetic acid and acetate ions should he/she mix to prepare a solution with a total volume of 500 mL?

asked Jan 22 in Chemical reactions by MarisaReich6 (470 points)

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1 answer 76 views

A chemistry student needs to predict the products of a reaction between aluminum and sulfuric acid. What chemical equation represents this reaction and what are the names and states of the products formed?

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

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1 answer 46 views

A chemistry student needs to identify an unknown compound using mass spectrometry. The compound has a molecular ion peak at m/z 120 and four major fragment ions at m/z 91, 77, 63, and 45. What is the molecular formula of the unknown compound?

asked Jan 22 in Analytical Chemistry by KarlaLeslie1 (310 points)

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1 answer 68 views

A chemistry student needs to identify an unknown compound found at a crime scene using mass spectrometry. The compound has a molecular weight of 286 g/mol and the mass spectrum shows a strong peak at m/z = 180 and a weaker peak at m/z = 148. What is the possible molecular formula of the unknown compound?

asked Jan 22 in Analytical Chemistry by HNSKieran194 (350 points)

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1 answer 49 views

A chemistry student needs to find the rate of a chemical reaction for a given set of concentrations and time, given the following reaction: 2H2 (g) + O2 (g) -> 2H2O (g)If the initial concentrations of H2 and O2 are 0.5 M and 0.2 M, and the reaction rate is 0.12 M/s, what is the concentration of H2O after 10 seconds?

asked Jan 22 in Chemical reactions by RodneyDeBern (630 points)

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1 answer 74 views

A chemistry student needs to find the percent composition of a compound with the empirical formula CCl. The compound has a molar mass of 98.96 g/mol. What is the percent composition of this compound?

asked Jan 22 in Inorganic Chemistry by GraceHershbe (410 points)

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