THE DENSITY OF MATTER

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A. Density: the mass of a substance (how much matter it has) divided by its volume (how much space it occupies).

where D = density (kg/m3)

m = mass (kg)

V = volume (m3)

Density is a very important quantitative property of matter -- it helps identify a substances every substance has a specific density. The density of a substance indicates how the particles of a substance are packed together win the substance.
The tighter the particles are packed, the higher the density of the substance.

The preferred SI (metric) unit for density is kg/m³

other units are also used: g/L, g/dm³, g/cm³, g/mL

note that: 1 kg/m³ = 1 g/L = 1 g/dm³

1 g/cm³ = 1 g/mL = 1000 kg/m³

B. Density Calculations:

1. EQUIVALENT UNITS OF DENSITY

Conversions:

1000 kg/m3 = _________g/cm3

5.0 g/mL = __________kg/m3

25.67 g/cm3 = ________g/L

2. Problems:

A young man wants to buy his sweetheart a friendship ring made of pure gold at Phoenix General Store and Tackle. The mass of the ring is 29.8 g. The young man remembers what he had learned in his Science class, and quickly takes out a graduated cylinder. He fills it up to the 20 mL mark with water, and throws the ring in. The level of water rises up to 22.64 mL. Is this substance real gold?

Solution:

To Calculate Density...

Conclusion:

From a Density Table in our book we see that the density of lead is 11300 kg/m3. Therefore we conclude that the substance is not gold.
This substance could be lead painted gold in colour!!!!