Question

Heptane and water do not mix, and heptane has a lower density (0.684 g/mL) than water (1.00 g/mL). A 100-mL graduated cylinder with an inside diameter of 3.16 cm contains 34.6 g of heptane and 34.0 g of water. What is the combined height of the two liquid layers in the cylinder? The volume of a cylinder is π r2h, where r is the radius and h is the height.

Answer 1

`h=100.8cm`

Step-by-step explanation:

Hello,

In this case, considering the density and mass of both water and heptane we first compute the volume of each one:

`V_(water)=(m_(water))/(\rho _(water))=(34g)/(1.00g/mL)=34mL\\ \\V_(heptane)=(m_(heptane))/(\rho _(heptane))=(34.6g)/(0.684g/mL)=50.6mL\\`

Now, the total volume is:

`V=50.6mL+34mL=84.6mL`

Which is equal to:

`V=84.6cm^3`

Then, by knowing that the volume of a cylinder is πr²h or π(D/2)²h, we solve for the height as follows:

`h=(V)/(\pi (D/2)^2) \\\\h=(84.6cm^3)/(\pi (3.16cm/2)^2) \\\\h=100.8cm`

Best regards.