Density = mass / volume
mass = 1.1 g
volume = length of side ^ 3 = [1.2 * 10^-5 km * 100000 cm/km]^3 = [1.2 cm]^3 = 1.728 cm^3
density = 1.1 g / 1.728 cm^3 = 0.64 g / cm^3
A
More concentrated means more collisions per unit volume, and as the volume stays the same and only concentration changes, the there are more collisions
A compound optical microscope or just a optical microscope is a microscope that uses light and has more than one lens.