# Question #03a15

##### 1 Answer

#### Answer:

The concentration of the sap should be 0.059 mol/L.

#### Explanation:

The sap will rise until the **hydrostatic pressure** due to the height of the sap column just balances the **osmotic pressure**.

The formula for **osmotic pressure** is

#color(blue)(|bar(ul( Π = cRT)|)# , where

#c# = molarity of solute#R# = universal gas constant#("8.314 kPa·L·K"^"-1""mol"^"-1"# )#T# = temperature (#"288.15 K"# )

The formula for **hydrostatic pressure** is

#color(blue)(|bar(ul( P = hρg)|)#

where

#h# is the height of the column#ρ# is the density of the sap (#"1100 kg·m"^"-3"# )#g# is the acceleration due to gravity (#"9.81 m·s"^"-2"# )

Our first task is to determine the hydrostatic pressure of a 13 m high column of sap.

Now, we calculate the concentration of sugar sap needed to generate this osmotic pressure.

The concentration of sugar sap is 0.059 mol/L.