Reversible Chemical Reactions

• Understand that in certain chemical reactions, the resulting products can react together to reform the original reactants.
• Identify these bidirectional processes as reversible reactions.
• Recognize and utilize the correct symbol to represent reversible reactions:

$A + B \rightleftharpoons C + D$

• Explain how the direction of a reversible reaction can be controlled by altering the external conditions.
• Describe the effect of heating and cooling on the reversible reaction between ammonium chloride, ammonia, and hydrogen chloride.