3.1.1 Density of Materials

• What is the formula for density?

  Density = mass/volume
• What is density measured in?

  kg/m3.
• What is mass measured in?

  Kilograms.
• What is volume measured in?

  m3.
• Which state has the lowest density?

  Gases.
• Which state has the highest density?

  Solids.
• A substance has a mass of 1,460kg and a volume of 0.2m3. What is the density of the substance?

  7300kg/m3.
• How to calculate the density of a solid experimentally:

  1. Measure the mass of the solid using a balance.
  2. If the shape is regular, measure the volume of the solid using geometry.
  3. If the shape is irregular, measure the volume of the solid by adding it to a displacement can filled with water. This will cause a volume of water exactly equal to the volume of the solid to flow into the measuring cylinder.
  4. Use the formula to calculate the density of the solid from the mass and volume measurements.
• A 447kg block of copper has a density of 8940kg/m3.

  What is the volume of this block of copper?

  0.05m3.
• The most common units of density are g/cm3 and kg/m3. To convert g/cm3 to kg/m3 you have to:

  Convert from g to kg and per cm3 to per m3. To convert from g to kg you need to divide by 1,000.

  To convert from per cm3 to per m3 you need to multiply by 1,000,000 (because a m3 is 1,000,000 larger, so there will be 1,000,000 x more particles in it). So overall, we have to multiply by 1,000.
• The density of sodium is 0.968 g/cm3. What is its density in kg/m3?

  968kg/m3.
• How to calculate the density of a liquid experimentally:

  1. Place an empty measuring cylinder onto a balance, then 'zero' the reading.
  2. Add some of the liquid to the measuring cylinder.
  3. Read the volume of the liquid from the measuring cylinder.
  4. Read the mass of the liquid from the balance.
  5. Use the density formula to calculate the density from the mass and volume measurements.
• Which two methods are used to reduce the uncertainty in experimental measurements of density?

  When measuring the density of liquids, use a larger volume of liquid & take multiple measurements and calculate the mean.