Properties of Matter

Bellringer – Week 3 1. Describe the pencil or pen you are using. Be very specific. If all of the pencils and pens in the classroom were mixed together would we be able to identify yours from your description?

Properties of matter can be divided into 2 categories: Physical Properties Properties that can be observed or measured without changing the identity of the matter Chemical Properties Properties that describe a substances ability to change into a new substance.

Physical Properties Basic Properties Color Odor Size (Mass,Volume) Shape Texture Complex Properties Thermal Conductivity State of Matter Malleability Ductility Solubility Density

Complex Properties Ductility-ability to bend without breaking Malleability-capable of being shaped Solubility-capability of being dissolved

(but any mass unit/volume unit is correct) Density Density is the amount of matter in a given space and the formula is: D = mass/volume It’s SI units are: g/ml, g/cm3, kg/m3 or kg/L (but any mass unit/volume unit is correct)

Density Density is a useful property for identifying an object because: 1. The density of a particular object is always the same at a given pressure & temperature. 2. The density of one substance is usually different from that of any other substance 3. Density does not change with the size of the object

Please Do Now Solve the following density problems: metal A block of aluminum occupies a volume of 15.0 ml and weighs 40.5 g. What is its density? Mercury metal is poured into a graduated cylinder that holds exactly 22.5 ml. The mercury used to fill the cylinder weighs 306.0 g. From this information, calculate the density of mercury.

The following liquids were spilled into a tank A green liquid that has a volume of 48 L and a mass of 36 kg A blue liquid that has a volume of 144 L and a mass of 129.6 kg A red liquid that has a volume of 96 L and a mass of 115.2 kg A black liquid that has a volume of 120 L and a mass of 96 kg

Density work cont’d 1. Calculate the density of each liquid: 2. Determine the order in which the liquids have settled in the tank: First (bottom) Second Third Fourth (top) 3. Use crayons to sketch the layers in the tank

Chemical Properties Chemical properties are not as easy to observe as physical properties Two of the main chemical properties are: Flammability – the ability to burn (aka: Combustible) Reactivity – when 2 substances combine, something happens! (explode, change color, make a noise or create an odor, bubble, fizz)

Chemical & Physical Properties of a Car Positive Properties Iron is strong, malleability, high melting point Iron is NON reactive with oil and gasoline Paint does not react with oxygen Negative Properties Iron is reactive with water and oxygen – It causes rust!!!

Physical & Chemical Changes

Physical Changes A physical change is a change that affects one or more of its physical properties. The substance involved remains the same even though it may change shape or form Physical changes can usually be undones All changes in phase are physical changes

Physical Change vaporization sublimation condensation < Melting Freezing >

Examples of Physical Changes Freezing water Cutting your hair Bending a paper clip Crushing up a piece of chalk Dissolving salt in water

Chemical Changes A chemical change occurs when one or more substances are changed into entirely new substances. Most chemical changes cannot be undone by physical means….but some can be undone by going through additional chemical changes.

Evidence of Chemical Changes Clues that a chemical change has occurred include: Change in color Fizzing or foaming Generation of heat, sound, light or odor A solid material called a precipitate is formed Difficult to reverse

Precipitate

Review: Physical or Chemical Change? Change in state Substance remains the same Reversible Did it dissolve? New substance is formed Change in color Heat or light given off Bubbles are formed Precipitate is formed Difficult to undo

Bellringer How could you calculate the density of water? Please explain the procedures and calculations you would use.

Bellringer What is volume? What are 3 ways to measure it?