Properties of Matter Physical Properties Ex.- color, shape, mass, volume, density Often identify objects based on physical properties Easy to observe Pg. 60 answers: 1. c2. d3. d4. a5. c6. a

Physical properties describe matter Can be observedCan be measured Stay constant for pure substances- can be used in identification Boiling & melting point constant if pressure remains the same State- physical form in which a substance exists

Density is a physical property How much matter is contained in a certain volume Determines whether an object will sink or float Calculated by dividing an object’s mass by its volume density=mass/volume D=m/V

Which is heavier: a golf ball or a ping-pong ball? Have similar volume: 14.1cm 3 Golf ball has mass of 45.9g Ping-pong ball has mass of 2.5g D=m/V D=2.5g/14.1cm 3 D=0.18g/cm 3 D=m/V D=45.9g/14.1cm 3 D=3.25g/cm 3 Unit for density is normally g/cm 3 cm3 is same as mL May see g/mL as unit (especially liquids) If 10.0cm 3 of ice has a mass of 9.17g, what is the density of ice? Mass= 9.17g Volume= 10.0cm 3 D= m/V D= 9.17g/10.0cm 3 D= 0.917g/cm 3

Density Practice Problems Pg D = 7.31g/cm 3 2.D = 3.26g/cm 3 3.m = 76g

Physical properties help determine uses of materials Are your socks clean? Property = odor Does your shirt match your pants? Property = color Do all your books fit in your backpack? Property = volume How are substances useful? Copper can conduct electricity well Used in power lines, telephone lines, and electric motors

Chemical Properties Generally not as easy to observe as physical properties Related to the specific elements that make up substances Describes how a substance changes into a new substance Either by combining with other elements or By breaking apart into new substances Examples of chemical properties: -reactivity -flammability Substance always has its chemical properties

Comparing Chemical & Physical Properties Physical properties: Can be observed without changing the identity of the substance Chemical properties: Can be observed only in situations in which the identity of the substance changes Many substances have similar physical properties but completely different chemical properties Baking soda and powered sugar both white powders Baking soda reacts with vinegar Powered sugar does not

Characteristic properties help to identify and classify substances Properties most useful in identifying a substance reactivity with acids solubility density Include both types- physical and chemical Always the same, no matter the sample size of the substance