Chapter 2 – section two - Physical Properties

• Physical properties describe matter.
• Some physical properties of matter include shape, color, size, mass, volume, density, melting point and boiling point.
• Melting point the temperature and pressure at which a solid becomes a liquid
• Boiling point the temperature and pressure at which a liquid becomes a gas
• State the physical form in which a substance exists, such as solid, liquid, or gas
• Density is a physical property.
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• Density is a measurement of how much matter is contained in a certain volume of a substance.
• A substance with a low density is “light” and a substance with a high density is “heavy” in comparison to other substances of the same volume.
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• Density the ratio of the mass of a substance to the volume of a substance
• Density is often measured in units of g/cm3
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• The equation for density is D = m/V
• Density = mass/volume
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• The density of a liquid or solid is usually reported in units of grams per cubic centimeter (g/cm 3 or instead of cm 3 - cc may be used for cubic centimeter)
• Density = mass/volume

Example - If 10.0 cm3 of ice has a mass of 9.17 g, what is the density of ice?

List the given and unknown values.

Given: mass, m = 9.17 g

volume, V = 10.0 cm 3

Unknown: density, D = ? g/cm 3

Write the equation for density. density = m/V or density = mass/volume

Insert the known values into the equation, and solve.

D = 9.17 g/10.0 cm 3

D = .917 g/cm 3

• Physical properties help determine uses.

• Physical properties are used to select substances that may be useful.
• Examples of useful physical properties include:
• low freezing point
• high boiling point
• water resistance
• flexibility
• electrical conductor
• heat conductor

Chemical Properties

• Chemical properties describe how a substance reacts.
• Chemical properties are related to the specific elements that make up substances.
• Chemical properties describe how a substance changes into a new substance when in contact with other elements.
• Reactivity the ability of a substance to combine chemically with another substance
• Flammability the ability of a substance to react in the presence of oxygen and burn when exposed to a flame

Comparing Physical and Chemical Properties

• Characteristic properties help to identify and classify substances.
• The table below compares some physical and chemical properties.