Physical vs. Chemical Properties The Study of Matter

Reviewing MATTER Matter: anything that has mass and takes up space Mass – the amount of matter in something Volume – the amount of space something occupies Which of the following is matter? A car? A box? You?

What is a property? Property: a characteristic of a substance that can be observed

Physical Property Physical property: a property that can be observed without changing the identity of the substance. Examples: mass volume color hardness texture melting point boiling point density solubility specific heat luster

More Physical Properties Malleability: the ability of metals to be hammered into a thin sheet EX – aluminum foil sheets Ductility: the ability to be stretched into a wire EX- Copper wire Magnetism: force of the attraction or repulsion that exist between like and unlike poles (North /South)

More Physical Properties Electrical Conductivity: the ability to carry a charge Conductors - allows electrons to flow easily Insulators - materials that do not allow electricity to flow through Semiconductors - material that has conductive properties between those of conductors and insulators

Special Physical Properties Melting point: the temperature at which a substance changes from a solid to a liquid at a given pressure Melting POINT of water = 0oC Boiling point: the temperature at which a substance changes from a liquid to a gas at a given pressure Boiling point of water = 100oC Freezing Point: the temperature at which a substance changes from a liquid to a solid at a given pressure

Change in Phases of Matter Occurs when there is a change in the amount of thermal energy Vaporization - liquid goes to a gas (gains energy) Evaporation Boiling Condensation - gas changes to a liquid (energy is lost) Sublimation-solid goes straight to a gas

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 vinegar Combustion

Density amount of mass per unit of volume. can be used to identify a substance. density of water = 1.0g/mL

Density Formula D = m/V D = g/mL D = g/cm3

Density Calculations Ex: A cube has a mass of 2.8 g and occupies a volume of 3.67 ml. Would this object float or sink in water? Mass = 2.8 g Volume = 3.67 mL D = 2.8g/3.67 mL D = 0.76 g/mL This object would float in water because its density is less than water (1.0 g/mL).

More Density Calculations Ex: A liquid has a mass of 25.6 g and a volume of 31.6 mL. Use the table below to identify the substance. M=25.6 g V=31.6 mL D = 25.6 g/31.6 mL D= 0.81 g/mL The substance is ethanol.