IPC Notes

Density

Density

density – the mass of an object per unit volume

ex) the density of a substance describes how tightly packed the molecules are

An object will float if it is less dense than the liquid it is immersed in.

ex) oil floats on

water because

oil is less dense

than water

An object will sink if it is more dense than the liquid it is immersed in.

ex) a rock will sink

in water because

it is more dense

than water

QUESTION #1: Why does diet coke float in water, but regular coke sinks in water?

Regular coke is more dense than diet coke because it contains 39 grams of sugar, whereas diet coke has 0.1 grams of Nutrasweet.

QUESTION # 2: A cruise ship is very heavy, so why does it float?

QUESTION #3: Which is more dense: ice or water?

QUESTION #4: Liquid A, Liquid B and Liquid C are all poured together. Liquid B is less dense than liquid C. Liquid A is more dense than liquid C. Which liquid would sink to the bottom? (Hint: draw a picture)

Density Calculations

D = m

V

D = density (g/mL or g/cm3)

m = mass (grams)

V = volume (mL or cm3)

Rearrange the formula for mass:

Rearrange the formula for volume:

QUESTION # 5: What is the density of a liquid that has a mass of 1.70 grams and a volume of 2 mL? D = m / V

Would it sink or float in water?

QUESTION # 6: What is the mass of a block of wood that has a volume of 5.6 cm3 and a density of 0.75 g/cm3?

QUESTION # 7: What is the volume of an object that has a mass of 42.3 g and a density of 3.25 g/cm3?