fe 3+ + scn- <-----> fescn2+

Apparatus and materials:
0.2 M Fe(NO3)3, 0.002M Fe(NO3)3, 0.002 M KSCN.

PRELAB:
for this section [fe3+]i = y [scn-]i = z and [fescn2+]eq = x
using the symbols y,z,x, fill in the ice char. note that the rxn starts w/ reacts. only at t=0.

I am confused on how to do this.

I assume this is a spetrophotometric determination of Fe^+3 or SCN^- or since the t=0 statement is made perhaps it is a reaction rate. You don't give enough other information for an outsider to know what is going on. What does the i stand for after the brackets. Incidentally, I know it takes a little more time but I don't think, in the end, that you are doing yourself a favor by using lower case letters.

both my shift buttons are broken sometimes it works. i think i got this question, another one is what special property of a substance encourages physical change of state?

One property is intermolecular forces--those forces between molecules within the material. If the intermolecular forces are weak it is easier for the molecules to break away from their neighbors and move from a liquid state, for example, to a gaseous state.

To answer this question, you need to understand how to set up an ICE (Initial, Change, Equilibrium) table for a chemical reaction.

In this case, the reaction is Fe3+ + SCN- ↔ FeSCN2+. Let's break down the steps:

Step 1: Identify the initial concentrations (at t=0) of the reactants and products:

[Fe3+]i = y (initial concentration of Fe3+)
[SCN-]i = z (initial concentration of SCN-)
[FeSCN2+]eq = x (equilibrium concentration of FeSCN2+)

Step 2: Set up the ICE table using the symbols from Step 1:

Fe3+ + SCN- ↔ FeSCN2+
Initial: y z 0
Change: -x -x +x
Equilibrium: y-x z-x x

Step 3: Analyze the values in the ICE table:

Based on the given information, the reaction starts with only reactants and no products at t=0. This means that the initial concentrations of FeSCN2+ is zero, i.e., [FeSCN2+]i = 0.

Therefore, you can substitute the value of [FeSCN2+]i in the ICE table with zero, resulting in:

Fe3+ + SCN- ↔ FeSCN2+
Initial: y z 0
Change: -x -x +x
Equilibrium: y-x z-x x

Now, you have successfully filled in the ICE chart using the given symbols y, z, and x.

Keep in mind that the values of y, z, and x depend on the specific concentrations provided in the problem. Make sure you accurately substitute these values in the final ICE table.