Final answer:
In a laboratory setting, the student determining the density of an unknown liquid measured the mass of an empty graduated cylinder and the volume of the liquid. Density calculation requires these two measurements, and density can also be used to find mass or volume if one is known. Temperature is an important factor affecting density.
Step-by-step explanation:
In the laboratory, when determining the density of an unknown liquid, a student likely measured the mass of an empty graduated cylinder and the volume of the unknown liquid.
Density is defined as the mass of a substance divided by its volume (D = m/v). To find the density of the unknown liquid, the student would first weigh the empty graduated cylinder, then add the liquid and weigh it again.
The mass of the liquid is determined by subtracting the mass of the empty cylinder from the mass of the cylinder with the liquid. The volume is read directly from the graduated cylinder.
To calculate the density of a material, divide the mass by the volume.
For instance, if a sample has a mass of 22.8 grams and a volume of 14.7 mL, the density would be calculated as 1.55 g/mL. Additionally, knowing the density, one can also calculate either the mass or volume if the other measurement is known, using dimensional analysis to ensure units are consistent and cancel appropriately.
Gases are generally less dense than liquids or solids at room temperature, and the density of materials can change with temperature. This is crucial to consider in laboratory settings where precision is important.