# Calculating an initial Cr2O72-(aq) concentration of 1.0 x 10-3 M and an initial C2H5OH(aq) concentration of 0.500M?

##### 1 Answer

(d) At 1.50 min,

(e) Use an initial

#### Explanation:

**(c)** Calculating concentration

The formula for absorbance **Beer's Law**:

#color(blue)(bar(ul(|color(white)(a/a)A = epsiloncl color(white)(a/a)|)))" "#

where

It states that the absorbance is directly proportional to the concentration of the sample. Thus,

We can rearrange this formula to give

In your problem,

∴

**(d)** Determining the new setup

You know that

You want to keep

Thus, if you double the path length

Start with