Making a Scatterplot

Open Excel document Set it up like the image on the right

Enter your data in both roles in the table Make sure YOUR DATA is in the “% change in mass” line

Highlight all of your data by dragging over the top

Click “insert” on the top ribbon Select the scatterplot option

On the menu that drops down, select the dots with no line option

It will create a graph that looks like this

On the graph, right click on one of the dots, and this menu should come up

Select “Add Trendline” from the options

Once you click “Add trendline”, this menu should pop up Check the box next to “Display Equation on Chart”

The Equation will pop up on your graph

We want the concentration of an isotonic solution An isotonic solution has no change in mass, so we will set y = 0 We want to know exactly where our line crosses the x axis

Then you just do some algebra My equation was y = - 103.5x + 18.78 Set y = 0 and solve for x 0 = -103.5x + 18.78 (subtract 18.78 from each side) -18.78 = -103.5x (divide each side by -103.5) .18 = x So this means .17m is my concentration of an isotonic solution I would plug in .17 for C in the –iCRT equation

Save your work somewhere you will be able to find it later, and continue by starting your lab report