Submitted by Sibrina Collins / College of Arts and Sciences at Lawrence Technological University on Sat, 03/03/2012 - 14:55
Forums

Colleagues,

What is the best strategy for teaching first year students how to be able to predict the products for chemical reactions? Ideas?

Sibrina

Chip Nataro / Lafayette College

Are you asking about the 'standard' Gen Chem 1 reactions (acid-base, precip and redox) or are you asking about bigger picture kinds of things.

Mon, 03/05/2012 - 14:33 Permalink
Sibrina Collins / College of Arts and Sciences at Lawrence Technological University

Hey Chip, standard GChem 1 reactions. I found some good resources to help the students where the best approach is to recognize the cations and anions from two reactants you are given and predict products.  I think this is a good approach because it forces them to know the fundamentals form the periodic table (alkali metals, +1 charge, halogens, -1, etc). But, there are also anions that they need to memorize too such as sulfate and carbonate. I was just wondering if anyone had other suggestions.

SNC

Thu, 03/15/2012 - 15:57 Permalink
Chip Nataro / Lafayette College

My biggest hint in gen chem is that if you don't get the products, it isn't redox.

Mon, 03/19/2012 - 12:34 Permalink
Joanne Stewart / Hope College

When I teach precipitation reactions and acid-base reactions, I always start by insisting that students memorize the strong acids (SA) and strong bases (SB). If they can recognize the strong acids and bases, they can predict a ton of chemical reactivity.

  1. Strong acids and bases completely dissociate in water.
  2. SA + SB, SA + weak base (WB), and SB + weak acid (WA) all "react completely."
  3. The anions derived from the strong acids (Cl-, NO3-, etc.) are always soluble (assume all other anions form precipitates).
  4. The cations derived from the strong bases (Na+, K+, Ba2+, etc.) are always soluble (assume all other cations form precipitates).

Of course, it's the exceptions to those last two that form the basis for qualitative analysis. For example, the "soluble" halides form precipitates with Ag+, Hg22+, and Pb2+.

Tue, 04/10/2012 - 12:22 Permalink