Values of density

Gasses have lower density than solid and liquid , an object that is less dense than water can float and that is why we could see many icebergs floating rather than getting sinked thus if any object that is above the water surface is less dense than water , as i said gasses have the lowest density let's take an example of them 

Gasses          

 Material          Density/kg/m cube

 Air                   1.29

 Hydrogen        0.09

 Helium            0.18  

 Liquids

 Material          Density/kg/m cube

 Water              1000

 Mercury           13,600

 Solid

 Material          Density/kg/m cube

 Ice                  920

 Wood              400 - 1200

 Glass              2500 - 4200 

 Gold                19,300 

This was a comparison of the density per kg of gas/liquid/solid 

Calculating Density

Rule : To calculate the density first we need to know the volume and the mass of the material

1. A sample of ethanol has a volume 240 cm cube , its mass is 190 grams . What is the density of ethanol ?

Step 1 : Mass M = 190 gram 

             Volume V = 240 cm 

              Density D = ? 

Step 2  : D = M/V 

               190 / 240 = 0.79 g/cm cube

 Measuring density

It has a mass of 2.8 kg 

1. Give the dimensions of the brick in meters

2. Calculate the volume of the brick

3. Calculate the density of the bricks 

1a. 0.215  into 0.1025 into 0.065 

      0.00143 m cube - Answer 

2a. Volume – Length into breadth into height = 

      215 into 102.5 into 65 = 

      1,437,187.5 

       In meter = 0.00144 m cube

3a. Mass = 2.8 kg

      Volume = 0.00144 

       D = 2.8 kg / 0.00144 

       1,944.444 m cube  

Answers

1. 6.77 - 3.37 = 3.4 

3.4 / 35 

0.09714 gram is the mass one match 

1. 22.218 

1. 0.2221 is the volume thus 6.77 - 3.37 = 3.4

3.4 / 0.2221 = 15.308 gram