Mississippi Science CHE.11

CHE.11 is a cluster heading. These are the individual standards under it.

• CHE.11.1

  Enrichment: Construct explanations to explain how to use Le Chatelier’s principle to predict the effect of changes in concentration, temperature, and pressure. ...

• CHE.11.3

  Enrichment: Use mathematical and computational thinking to calculate an equilibrium constant expression for a reaction.

01

What Students Need to Do

Students track a reversible reaction until forward and reverse reactions happen at the same rate, even though molecules keep reacting. They use concentration data to recognize equilibrium, write equilibrium constant expressions, and predict what happens when conditions change.

02

What Mastery Looks Like

Given concentration readings, students identify when the values level off and write Kc with coefficients as exponents. They predict shifts after a change in concentration, temperature, or gas pressure. They know that only a temperature change alters K.

03

Common Misconceptions

Students may think reactions stop at equilibrium or that reactant and product concentrations must be equal. They may put coefficients in front of concentrations instead of using exponents, or think higher pressure always favors products.

04

How to Assess It

Exit ticket: For N2(g) + 3H2(g) ⇌ 2NH3(g) + heat, write Kc, predict the shifts after adding H2, heating, and compression, and explain what happens to reaction rates at equilibrium.

1. 01

   Start with ten beads in cup A and four in cup B; move three A-to-B and one B-to-A, then two each way per round.

2. 02

   Ask students to explain why heating N2O4(g) ⇌ 2NO2(g) produces more brown NO2 when splitting N2O4 absorbs heat.

3. 03

   Race through cards for N2(g) + 3H2(g) ⇌ 2NH3(g): add H2, compress the container, and write Kc.

4. 04

   Compare a sealed soda bottle with one just opened, and explain why dissolved CO2 escapes when gas pressure drops.

• CHE.9

  Enrichment: Students will understand the nature and properties of acids, bases, and salt solutions.

• CHE.10

  Enrichment: Students will understand that energy is exchanged or transformed in all chemical reactions.