Prepare written answers to the following exercises:

 

1.     Imagine that you work at a company that prepares chemical solutions. You are asked to label a solution to sell to different customers. One customer is a hospital, another is a chemistry lab at a university, and a third is a physics lab at a university. You added 900 kg of NaCl in a 100-liter container and filled it with water to a volume of 100 liters. Assume standard (STP) conditions.

 

Determine the following:

 

·         Mass percentage of the solution for the customer in the hospital

·         Molarity for the customer in the chemistry lab

·         Molality for the customer of the physics lab

 

2.     A researcher is often required to prepare solutions in the lab. Typically, a lab provides a concentrated solution. This solution must be diluted to the proper concentration. Hydrochloric acid is a common stock solution that is typically purchased at 37.0% HCl concentration (density = 1.20 g/ml). You must make 100 ml of 0.25 M HCl to do a DNA extraction experiment. How much of the 37.0% HCl concentration stock do you need to prepare this solution?

 

3.     The Haber–Bosch process for fixation of nitrogen is one of the more important chemical reactions ever invented. Without the invention of this process, which is used to make ammonia for fertilizer, the world’s population would not be as large as it is today.

 

N₂(g) + 3H₂(g) à 2NH₃(g)

 

·         List three ways in which the yield of ammonia in the reaction above can be improved for a given amount of H₂.

 

·         Additionally, explain the principle behind each method.