Properties of Matter Lesson 7
Jan 01, 2016
Properties that Define Matter
Substances are defined by their Properties. A different word for properties is characteristics.
You use physical properties when you describe a friend. For example you may talk about the person’s hair colour, eye colour, and height.
Observations are pieces of information we collect as we use our senses of sight, touch, hearing taste and smell.
We will never use TASTE in the lab. Observations can be made using several
senses. Sight, Smell, Touch, Taste and hearing.
What is a physical property?
A characteristic or description of a substance that may help to identify it. Physical properties observed by the senses are in the following table
Colour Texture Odour Clarity Taste
Colourless, white, black
Fine, course, smooth, gritty
Odourless, spicy, sharp, burnt,
Clear, cloudy, opaque
Sweet, sour, salty, buttery
Using observations is important in science and daily life.
Automobile mechanics SEE a car’s oil level HEAR how the engine is running SMELL what is happening in the engine
compartment
Qualitative properties
Qualitative properties describe how something appears, sounds, or smells. A qualitative property might also explain how flammable or reactive a substance is.
Qualitative properties are useful for some things, but not for others.
People such as Engineers must know the exact properties of the materials they use. Imagine if an engineer made a bridge of steel that was not strong enough, or a laptop computer out of plastic that melted when the computer heated up!
Quantitative properties
Quantitative properties use numbers to record exact measurements. “Quantity” refers to a number and a unit such as 25 mL
Properties of matter
Properties of Matter
Qualitative Properties
Example: The liquid is warm
Quantitative Properties
Example: The liquid is a 45 ° C
Physical Properties
-A physical property describes a characteristic of a substance that can be observed or measured without changing the composition of matter.
Example: Melting Point, Boiling Point
When water freezes it expands due to a special bonding between water molecules. Larger volume with the same mass = Less
dense This is why ice floats
Observing Physical Properties
Property Description Examples What it looks like
Colour and lustre
The light the substance reflects gives it colour and lustre (shine)
The names for somesubstances, such as gold,are also the names of colours. Gold has lustre; concrete is dull
Observing Physical Properties
Property Description Examples What it looks like
Conductivity
Conductivity is the abilityof a substance to conduct electricity or heat. Asubstance that conductselectricity or heat is called a conductor. A substance with little or no conductivity is an insulator.
Most metals are good conductors. Copper is a very good conductor of electricity and so is used to make electric wires. Styrofoam® and glass are insulators.
Property Description Examples What it looks like
Density Density is the amount ofmass in a given volume ofa substance.D = m/v
The density of pure water is 1 g/mL. The density of gold is 19 g/mL. Water is denser than oil, but gold is denser than water.
Observing Physical Properties
Property Description Examples What it looks like
Ductility Any solid that can bestretched into a long wire is said to be ductile.
Copper is a commonexample of a ductile material.
Observing Physical Properties
Property Description Examples What it looks like
Hardness Hardness is a substance’sability to resist being scratched. Hardness isusually measured on the Mohs hardness scale from1 to 10.
The mineral talc is the softest substance on the Mohs hardness scale (1). Emerald is quite hard (7.5). Diamond is the hardest(10).
Observing Physical Properties
Property Description Examples What it looks like
Malleability A substance that can bepounded or rolled intosheets is said to be malleable.
Aluminum foil is an example of a malleable substance.Metals such as gold and tin are also malleable.
Observing Physical Properties
Property Description Examples What it looks like
Viscosity Viscosity is the resistance of a fluid to flow.
Honey has a high viscosityCompared to water.
Practical applications
The Viscosity of oil keeps engines running. The numbers on containers of engine oil give the oil’s viscosity.
Ideally, oil should be thin enough to flow easily when an engine is cold. But it needs to remain thick enough to protect an engine when it is hot.
Thicker oils can handle higher temperatures before the oil is chemically broken down and does not function properly.
The lower the number, the thinner the oil and the easier it flows.
You need thin oil in the winter during cold temperatures because the oil still needs to be able to flow when the engine is cold.
Many cars use multi grade oil. These oils are effective over a wide range of temperatures.