Equilibrium Expressions in Chemistry

This video tutorial explains how to write equilibrium expressions for chemical reactions. It covers the basic rule of placing products over reactants and emphasizes the importance of using coefficients as exponents in the expression. The tutorial provides examples to illustrate these concepts and discusses the inclusion of states of matter, focusing on gases and aqueous compounds, while excluding liquids and solids due to their high concentration. The video concludes with a summary of the key points discussed.

What is the basic rule for writing an equilibrium expression?

• Reactants over products

• Products over reactants

• Sum of products and reactants

• Difference between products and reactants

In an equilibrium expression, what is done with the coefficients from the balanced equation?

• They are added to the expression

• They are subtracted from the expression

• They are used as exponents

• They are ignored

When writing the equilibrium expression for 2NO2 ⇌ N2O4, what is the correct expression?

• [NO2]^2 / [N2O4]

• [N2O4]^2 / [NO2]

• [NO2] / [N2O4]^2

• [N2O4] / [NO2]^2

What is the significance of using square brackets in equilibrium expressions?

• They represent pressure

• They show the temperature

• They denote concentration

• They indicate the phase of the compound

In the expression for SiCl4 and H2, why is the coefficient of H2 not written?

• Because it is a liquid

• Because it is a gas

• Because it is a solid

• Because its coefficient is 1

What is the equilibrium expression for the reaction: SiH4 + 2Cl2 ⇌ SiCl4 + 2H2?

• [SiH4][Cl2] / [SiCl4][H2]

• [SiCl4]^2[H2] / [SiH4][Cl2]

• [SiH4][Cl2]^2 / [SiCl4][H2]^2

• [SiCl4][H2]^2 / [SiH4][Cl2]^2

Which states of matter are included in equilibrium expressions?

• Solids and liquids

• Gases and aqueous solutions

• Only gases

• Only liquids

Why are liquids and solids not included in equilibrium expressions?

• They have variable concentrations

• They are not part of the reaction

• Their concentrations are too high to change

• They are always in excess

In the context of equilibrium expressions, what does the term 'aqueous' refer to?

• A solid dissolved in water

• A gas dissolved in water

• A liquid dissolved in water

• A substance dissolved in water

What happens to the equilibrium expression if a reaction involves a solid reactant?

• The solid is treated as a liquid

• The solid is treated as a gas

• The solid is excluded from the expression

• The solid is included in the expression