Molar relationships: Observing a single displacement reaction
Summary
In this chemistry lab, the students will investigate a single replacement reaction while also determining mole ratios to determine percent yields.
CollapseLearning Goals
Learning Goals:
1. Determine type of reaction is occurring in this lab
2. Use knowledge of molar ratios to determine grams of product produced
Key Concepts:
1. Determining theoretical yields/losses using molar conversions
2. Understanding types of reactions
Terms:
1. Single replacement reactions
2. Theoretical yield
3. Molar ratios/conversions
1. Determine type of reaction is occurring in this lab
2. Use knowledge of molar ratios to determine grams of product produced
Key Concepts:
1. Determining theoretical yields/losses using molar conversions
2. Understanding types of reactions
Terms:
1. Single replacement reactions
2. Theoretical yield
3. Molar ratios/conversions
Context for Use
This is used in my chemistry class (11th - 12th grade). It is a short lab that I use while talking about chemical reactions, but could also be used in a unit on molar conversions. About 15 minutes in 2 different class periods is all that is needed. It would be easy to adapt to many other situations. No special equipment is necessary. By the time this lab is used, students should have mastered the concept of determining molar mass using the periodic table and writing out chemical formulas.
Description and Teaching Materials
Reagants: Copper (II) Chloride, distilled water and iron nails
Materials: beaker, stirring rod, sandpaper, balance
Intro: The students have looked at different kinds of reactions, but they have not been discussed in detail. I tell them that it will be one of the reactions they know and that they should think about what all the chemicals are "doing" in the reaction. We also review molar conversions before we begin.
The experiment starts by having the students make a copper solution. They then place two iron nails in the solution and allow it to sit over night. They then determine how grams of copper produced and iron lost using molar ratios and conversions.
Close: At the ens of the lab, we brainstorm other chemical reactions that are like the one in lab.
This activity is adapted from another source.
Moles of Copper and Iron Lab (Microsoft Word 76kB Sep25 07)
Materials: beaker, stirring rod, sandpaper, balance
Intro: The students have looked at different kinds of reactions, but they have not been discussed in detail. I tell them that it will be one of the reactions they know and that they should think about what all the chemicals are "doing" in the reaction. We also review molar conversions before we begin.
The experiment starts by having the students make a copper solution. They then place two iron nails in the solution and allow it to sit over night. They then determine how grams of copper produced and iron lost using molar ratios and conversions.
Close: At the ens of the lab, we brainstorm other chemical reactions that are like the one in lab.
This activity is adapted from another source.
Moles of Copper and Iron Lab (Microsoft Word 76kB Sep25 07)
Teaching Notes and Tips
I find that if I review molar conversion before hand and give them some example scenarios, they have an easier time figuring out what they need to do at the conclusion of the lab.
Assessment
I correct the questions themselves at the closure of the lab, but I also give a quiz the following day with a different scenario. I also ask questions like, would this experiment work if we started with iron solution and a copper wire.
Standards
3. The conservation of atoms in chemical reactions leads to the principle of conservation of matter and the ability to calculate the mass of products and reactants. As a basis for understanding this concept:
e. Students know how to calculate the masses of reactants and products in a chemical reaction from the mass of one of the reactants or products and the relevant atomic masses.
e. Students know how to calculate the masses of reactants and products in a chemical reaction from the mass of one of the reactants or products and the relevant atomic masses.