What is the density of lead if a piece of lead 1 cm by 20 cm by 30 cm has a mass of 6800 grams

The density of the lead is 11.3 g/cm³.

V = lwh = 30 cm × 20 cm × 1 cm = 600 cm³

Density = 6800 g/600 cm³ = 11.3 g/cm³

Note: The answer can have only one significant figure because that is all you gave for the height of the block. However, I calculated the density to three significant figures.

h let me think

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.