Monday,+Oct+31

Stoichiometry !!!



Slides 33-39

Stoichiometry: Big name…simple concept

Example: How many grams of ammonia can be produced when 25.5 grams of nitrogen reacts with excess hydrogen?

25.5 grams x grams

N2 + 3 H2 à 2 NH3

moles moles

The rules of making a map:


 * Grams are written above the reactant/product; moles are written below
 * Find your starting position i.e. write down the given information in the appropriate position (25.5 grams nitrogen)
 * Place an “x” in the position that will answer the question (How many grams of ammonia?)
 * Draw arrows from the starting point to the ending point. Remember, diagonal arrows are not allowed. __And__ horizontal arrows are not allowed across the top (i.e. gram-to-gram conversions)
 * The number of arrows that you draw indicates the number of conversion factors that you will need
 * Set up the correct number of conversion factors and use dimensional analysis to perform the conversions in order from start to finish
 * You may start and/or end at any position along the map. You may even perform calculations in reverse order.

Can’t get there from here?

The Ideal Gas Law, molarity or density may be used as a bridge to get from given information onto the map. You may then proceed as usual.

Assignment: 99-105 odd; Read 3.11