Density is defined as the mass in a unit of volume.
In the SI unit system, mass is measured in kg and volume is measured in m3, thus, the unit of density is kg/m3 (kilogram per cubic meter). But this is inconvenient for most substances, therefore, g/cm3 (gram per cubic centimeter) is a more common unit of density.
Densityis a characteristic property of matter. We can differentiate substances by using their densities.
In order to calculate the density of an object,first we measure its mass with a scale, thenwe find its volume by measuring it with aruler, if it has a regular shape. Otherwise weuse the graduated cylinder method forirregular objects, and liquids. Then, bydividing mass by volume, we find the densityof the object.
What is the volume of 24 tons ofcement? (dcement = 3000 kg/m3)Calculate the mass of copperhaving the same volume as 31,5 gof silver. Use Table 1.7.
A bottle has a mass of 70 g when itis empty, 90 g when it is full ofwater and 96 g when it is full of aliquid. What is the density of theliquid in g/cm3 and kg/m3 ?
Calculate the mass of air (at 0° C)in a room having dimensions of 3m, 6 m, 5 m. See Table 1.7.
The density of a mixture is found by dividing the total mass of the mixture by its total volume.
1.3 kg of a liquid and 2 kg ofwater are mixed in a container.Find the density of the mixture.Take dliquid = 1.3 g/cm3 and dwater= 1 g/cm3.
Two different substances ofvolumes 200 cm3 and 300 cm3 aremixed to make an alloy. If theirdensities are 1.2 g/cm3 and 1.6g/cm3 respectively, find thedensity of the alloy.
One complete rotation of eartharound its axis is called one day. Itis equal to 24 hours (h), 1 hour is60 minutes (min) and 1 minute is60 seconds (s). The unit of time isthe second. A stopwatch or clockis used to measure time.
What is the equivalent of one weekin terms of hours, minutes andseconds?