7.2.2 The extent of a reaction from the magnitude of Kc

1.       What does the word magnitude mean?

Magnitude means size. It’s how big something is. Ignore the direction and the positive or negative sign.

2.       Explain why the three reactions above do not have units for Kc

Because the amount of term on the numerator and denominator cancel out, there are same amount of terms so the unit cancel out. It can also be said the amount of moles of reactant is equal to the amount of mole of the product.

3. Deduce the extent of the reaction if Kc is

a. significantly larger than 1

This means that there is lots of product being produce in comparison to the reactant. The numerator (concentration of product) is significantly bigger than the denominator (concentration of reactant). The number of moles of product is bigger than the number of moles of the reactant. So the reaction goes nearly to completion. At equilibrium.

b. between 0.01 and 100

This means that there is amount the same significant concentration product and reactant presented at equilibrium. The concentration of product (numerator) is about the same as the concentration of reactant (denominator). The amount of moles of product is about the same as the number of mole of reactant.

c. extremely small

This means that the reaction barely proceeds. At equilibrium, there is significantly more concentration of reactant compare to the concentration of the product. The amount of moles of reactant is bigger than the amount of moles of product.