properties of matter. what is a property? property: a characteristic of a substance that can be...

Properties of Matter

What is a property?

• Property: a characteristic of a substance that can be observed

Physical Property

• malleability: the ability to be hammered into a thin sheet

• ductility: the ability to be stretched into a wire

• melting point

• boiling point

• density

• solubility

• specific heat• luster

Physical property: a property that can be observed without changing the identity of the substance.

Special Physical Properties

Melting point: the temperature at which a substance changes from a solid to a liquid at a given pressure

water = 0oC

Special Physical Properties

Boiling point: the temperature at which a substance changes from a liquid to a gas at a given pressure

water = 100oC

Chemical Properties

• Chemical property: a property that can only be observed by changing the identity of the substance

• Examples:• flammability

• ability to rust

• reactivity with acids

Physical Change

A physical change occurs when the substance changes state but does not change its chemical composition.

The form or appearance has changed, but the properties of that substance are the same.

Chemical ChangesA chemical change occurs when a substance changes into something new. This occurs due to heating, chemical reaction, etc. You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes.

What kind of change is it if someone...

• Mixes vinegar and baking soda?

Chemical change

What kind of change is it if someone...

• Tears up paper?

Physical change

• Mixes salt and water?

Physical change

What kind of change is it if someone...

• Burns paper?

Chemical change

• Evaporates salt water?

Physical change

Density

• Density is a measure of how matter is squeezed into a given space

• Density = mass/volume• g/cm3 or g/mL• Density is an intensive

property• Density is constant for

any given material directly proportional

What happens to the density of a chocolate bar when you break it in two?

When a loaf of bread is squeezed does its density increase?

A loaf of Wonder bread weighs 20.0 oz. and has the dimensions 25 cm x 9 cm x 12.5 cm. If the loaf is compressed by ½ does the density increase?