Using the ideal gas law to determine the molecular weights of gases. Solution in MS Word.

At a given temperature a certain number of grams of CH4, when placed in a 10 L vessel, exerts a pressure of 0.240 atm. An equal number of grams of gas B, when placed in a 12 L container at the same temperature, exerts a pressure of 0.145 atm. Calculate the approximate molecular weight of gas B.

Determining the initial mole and mass fractions of oxygen and nitrogen in a mixture using Dalton's law of partial pressure. Solution in MS Word.

A reaction vessel contained 5 liters of a mixture of N2 and O2 gases at 25oC and 2 atm pressure. The oxygen in the mixture was completely removed by causing it to oxidize with an excess of electrically heated zinc wire contained in the vessel to non-volatile solid ZnO. The pressure of N2 that remained (measured again at 25oC) wa ...continues

Metric unit conversions and determining the molarity of a solution. Attachments in MS Word.

Convert 1) 75 mg/dL to mg/L 2) 592 uL to mL 3) What is the molarity of 45.0 g of NaCl dissolved in 1 L of water?

Determining the order of a chemical reaction using the dataset provided. Understanding first-order reaction kinetics and the concept of half-life. Attachments in Word.

In an aqueous solution, glucose decomposed according to the results shown below. (a) Demonstrate that the reaction is first order. (b) Calculate the rate constant for the decomposition process. (c) Calculate the half-life (t1/2) for glucose under the specified conditions. Glucose decomposition results: Time (min), Glucose ...continues

Using experimental results to determine the order of a chemical reaction and the rate constant from your understanding of chemical kinetics and species half life.

A reaction is defined by the following scheme: X à  Y When the concentration of X in a solution is 1.02 M, the half-life (t1/2) is 160 seconds. When the concentration of X in solution is 2.05 M, the half-life (t1/2) is 80 seconds. The above information applies when the reaction takes place at 25 degrees Celsius. ( ...continues

Understanding buffers and weak acids.

Ascorbic acid (vitamin C) has a pKa of 4.2 at 24 degrees Celsius. State the pH of the solution when the ratio of unprotonated to protonated forms of ascorbic acid is (a) 1:1 (b) 1:10 (c) 10:1 (d) 1:3 (e) Which form of ascorbic acid predominates at physiological pH?

Understanding Gibbs Free Energy change. Identifying reactions that are thermodynamically spontaneous.

The attached problem file shows the standard Gibbs Free Energy Change for two reactions. Considering these values, which reaction is more favoured or spontaneous? A reaction with a delta Go = 16 kcal mole-1? Or a reaction with a delta Go = -16 kcal mole-1?

Understanding how the equilibrium constant (Keq) relates to enthalpy change. Introductory thermodynamics. Attachment in Word.

Which reaction is more exothermic? A reaction with Keq=500 or a reaction with Keq=0.002?

Understanding acid strength, pKa.

Picric acid (C₆H₃N₃O₇) has a pKa of 0.3. Formic acid (CHO₂H) has a pKa of 3.7. Which is the stronger acid?

Understanding acid-base chemistry.

Amide ion (H₂N-) is a stronger base than the hydroxide ion (OH-). Which would you expect to be a stronger acid, NH₃ or H₂O? Why?