heptane and water do not mix, and heptane has a lower density (0.684g/mL) than water (1.00g/mL). A 100mL graduate cylinder with an inside diameter of 3.10 cm contains 39.90g of heptane and 34.00g of water. What is the combined height of the two liquid layers in the cylindar?

I figure out that the heptane is 39.90/0.684=58.3ml
water is 34.00/1=34.00ml

I know the diameter is 3.10cm and to get the radius I divide 3.10/2=1.55 and then I raise it by 2 which it 2.4025cm^2.

I don't know to get the rest

Wouldn't it be done this way?

pi*r^2*h = volume.
You know pi and r and you know the volume is 58.333+34.000 =- ? so solve for height. Then round to 4 significant figures. (Note: Since you know grams to 4 s.f., I would not round to 58.3 but keep it at 58.333 and round at the end.)

To determine the combined height of the two liquid layers in the cylinder, you need to calculate the heights of each layer individually and then add them together.

To calculate the height of the heptane layer, you can use the formula for the volume of a cylinder:

Volume = pi * radius^2 * height

Rearranging the formula, you can solve for the height:

Height = Volume / (pi * radius^2)

For the heptane layer, the volume is 58.3 mL and the radius is 1.55 cm (or 0.0155 m). Plugging these values into the formula:

Height (heptane) = 58.3 mL / (pi * (0.0155 m)^2)

Calculate this value to find the height of the heptane layer.

Next, to calculate the height of the water layer, you can apply the same formula with the volume of 34.00 mL and the radius of 0.0155 m:

Height (water) = 34.00 mL / (pi * (0.0155 m)^2)

Calculate this value to find the height of the water layer.

Finally, add the height of the heptane layer and the height of the water layer to get the combined height of the two liquid layers in the cylinder.

To find the combined height of the two liquid layers in the cylinder, you need to determine the volumes of heptane and water and then calculate the total height.

You've correctly calculated the volumes of heptane and water:
Heptane volume = 58.3 mL
Water volume = 34.00 mL

Now, to find the height occupied by each liquid, you need to divide their volumes by the cross-sectional area of the graduate cylinder.

The cross-sectional area can be calculated using the formula for the area of a circle:
Area = π * radius^2

You've correctly calculated the radius:
Radius = 1.55 cm

Now you can calculate the cross-sectional area (A):
A = π * (1.55 cm)^2

Using the value of π as approximately 3.14:
A ≈ 3.14 * (1.55 cm)^2

You can simplify the calculation and find the cross-sectional area, which will give you the height per unit of volume for each liquid.

Now, let's find the height of each liquid layer:
Heptane height = Heptane volume / A
Water height = Water volume / A

Finally, to calculate the combined height of the two liquid layers, add the heptane height and the water height together.

Combined height = Heptane height + Water height

This will give you the total height of the two liquid layers in the cylinder.