A flask contains 25.0 mL of diethyl ether weighth 18.74 µg (micrograms). What is the density of the diethyl ether and grams per liter?

mass = volume x density

Solve for density in g/mL and convert to g/L. OR you can convert mL to L and ug to g first, then divide to obtain g/L directly.

Density is simply mass per unit volume.

ρ = m / V

Useful conversions:
1 L = 1000 mL
1 g = 1000000 µg
Substitute the values to the formula, and convert.

To find the density of diethyl ether, you need to divide the mass of the substance by its volume. In this case, the mass is given in micrograms (µg) and the volume is given in milliliters (mL), so we need to convert the units to be consistent.

First, let's convert the mass from micrograms to grams. Since there are 1,000 micrograms in 1 milligram (mg) and 1,000 milligrams in 1 gram (g), we can convert micrograms to grams by dividing by 1,000 twice:

18.74 µg ÷ 1,000 ÷ 1,000 = 0.00001874 grams

Next, we need to convert the volume from milliliters to liters. Since there are 1,000 milliliters in 1 liter, we can convert milliliters to liters by dividing by 1,000:

25.0 mL ÷ 1,000 = 0.025 liters

Now that we have the mass in grams and the volume in liters, we can calculate the density by dividing the mass by the volume:

Density = mass / volume
Density = 0.00001874 grams / 0.025 liters = 0.0007496 grams per liter

Thus, the density of diethyl ether is 0.0007496 grams per liter.