Question

b) A box with an open top and a square base must have a volume of 32,000 cm2. Find the dimensions of the box that minimizes the amount of material used. Exp.5 CHEMICAL EQUILIBRIUM Date: Section: Name: Experiment 5: EXPERIMENTS IN CHEMICAL EQUILIBRIUM Prelaboratory Questions Note: This prelab covers 2 experiments, therefore 10 marks have been assigned (instead of the usual 5). No prelab is required for the second week, except, of course, for those of you who for some reason might have missed the first week. to it 1. (4 marks) Write a brief summary, in your own words, of the purpose of the experiments (Parts I and 2) and the steps you will follow. One page - maximum. 2. (1.5 marks) Write the expression for the equilibrium constants for the following reactions: N(g) 3H2(g) 2NH3(g) a. (3)O 2SO(g) b. 2SO(g) + NH Cl(s) NH(g) + HCl(g) c. 3. (3 marks- established. Explain how and why the position of equilibrium will shift in response to the following changes: 1 here, 2 on next page) For reaction 2(a) above, suppose equilibrium has been Additional nitrogen is added to the system. a.

Answer 1

The equilibrium expression is the product of the concentrations of products divided by the product of the concentrations of reagents. In the reaction:

cC + dD aAbB

the equilibrium expression is:

[CC[D1 K = [A]a [Bb

Note that the stoichiometric coefficient transforms into an exponent.

When you have gases, instead of concentration you must write the partial pressure of the species. When you have pure solids or liquids you never include them in the expression. So:

a) The expression is:

PNHS K = PN P H2

b)

K = S* Po

c)

К- Руня * Рнсі

(Remember not to write terms for pure solids or liquids, in this case NH₄Cl is a solid and must not be written)