Final answer:
Gases can be collected by displacing water in a pneumatic trough, and ammonia is prepared in the laboratory by reacting nitrogen with hydrogen in a stoichiometrically balanced equation, using ideal gas laws to quantify the amounts needed.
Step-by-step explanation:
There are several methods for collecting gases in a laboratory setting, each with its own application depending on the type of gas and the nature of the chemical reaction producing it. One common method is collecting gases over water using a pneumatic trough. This technique involves displacing water in an inverted tube or bottle with the gas, allowing it to be captured and stored.
The laboratory preparation of ammonia (NH3) typically involves a reaction between nitrogen gas (N2) and hydrogen gas (H2). According to the balanced chemical equation, N2(g) + 3H2(g) → 2NH3(g), one mole of nitrogen reacts with three moles of hydrogen to produce two moles of ammonia. When producing a large volume of ammonia, the stoichiometric requirements can be calculated using ideal gas laws, which relate the volume, temperature, and pressure of a gaseous system to the amount of substance present in moles.