2 Bellringer – Week 31. 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?
3 Properties of matter can be divided into 2 categories: Physical PropertiesProperties that can be observed or measured without changing the identity of the matterChemical PropertiesProperties that describe a substances ability to change into a new substance.
4 Physical Properties Basic Properties Color Odor Size (Mass,Volume) ShapeTextureComplex Properties Thermal Conductivity State of Matter Malleability Ductility Solubility Density
5 Complex Properties Ductility-ability to bend without breaking Malleability-capable of being shapedSolubility-capability of being dissolved
6 (but any mass unit/volume unit is correct) DensityDensity is the amount of matter in a given space and the formula is:D = mass/volumeIt’s SI units are:g/ml, g/cm3, kg/m3 or kg/L(but any mass unit/volume unit is correct)
7 DensityDensity 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 substance3. Density does not change with the size of the object
8 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 g. From this information, calculate the density of mercury.
9 The following liquids were spilled into a tank A green liquid that has a volume of 48 L and a mass of 36 kgA blue liquid that has a volume of 144 L and a mass of kgA red liquid that has a volume of 96 L and a mass of kgA black liquid that has a volume of 120 L and a mass of 96 kg
10 Density work cont’d1. 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
11 Chemical PropertiesChemical properties are not as easy to observe as physical propertiesTwo 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)
12 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 oxygenNegative Properties Iron is reactive with water and oxygen – It causes rust!!!
14 Physical ChangesA 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 formPhysical changes can usually be undonesAll changes in phase are physical changes
16 Examples of Physical Changes Freezing waterCutting your hairBending a paper clipCrushing up a piece of chalkDissolving salt in water
17 Chemical ChangesA 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.
18 Evidence of Chemical Changes Clues that a chemical change has occurred include:Change in colorFizzing or foamingGeneration of heat, sound, light or odorA solid material called a precipitate is formedDifficult to reverse
20 Review: Physical or Chemical Change? Change in stateSubstance remains the sameReversibleDid it dissolve?New substance is formedChange in colorHeat or light given offBubbles are formedPrecipitate is formedDifficult to undo
21 Bellringer How could you calculate the density of water? Please explain the procedures and calculations you would use.
22 BellringerWhat is volume?What are 3 ways to measure it?