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

Answer:

$h=100.8cm$

Explanation:

Hello,

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

$V_{water}=\frac{m_{water}}{\rho _{water}}=\frac{34g}{1.00g/mL}=34mL\\ \\V_{heptane}=\frac{m_{heptane}}{\rho _{heptane}}=\frac{34.6g}{0.684g/mL}=50.6mL$

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:

$h=\frac{V}{\pi (D/2)^2} \\\\h=\frac{84.6cm^3}{\pi (3.16cm/2)^2} \\\\h=100.8cm$

Best regards.