The fourth (last) one in 2-8-8-2.
Answer:

Explanation:
Percent yield is a ratio of the actual yield to the theoretical yield. It is found using this formula:

The actual yield is 12 liters, because that was actually produced in the lab.
The theoretical yield is 20 liters, because that was the expected yield.



For this reaction, the percent yield is 60%.
Answer:
D. Number of electrons
Density is the measure of a material's mass per unit volume, used in many aspects of science, engineering and industry. Density can be calculated by dividing an object's mass by its volume. Since different materials have different densities, measuring an object's density can help determine which materials are in it. Finding the density of a metal sample can help to determine its purity.When measuring liquids and regularly shaped solids, mass and volume can be discovered by direct measurement and these two measurements can then be used to determine density. Using a pan balance, determine and record the mass of an object in grams. Using a vernier caliper or ruler, measure the length, depth and width of the object in centimeters. Multiply these three measurements to find the volume in cubic centimeters. Divide the object's mass by its volume to determine its density. Density is expressed in grams per cubic centimeter or grams per milliliter.
(this can be split into two paragraphs)
There are 3 sig figs. 8 and 2 are obvious. The ending 0 is significant because it is at the end of a decimal number, and doesn't have to be measured.