2(2.1) Physical Properties of Matter can be observed or measured without changing the composition of the sampleExamples: color, phase, melting or boiling point, density, hardness, odor, taste
3States of Matter Solid (s) - definite volume and shape Liquid (l) - definite volume, but not shapeGas (g) - no definite volume or shapePlasma - highly ionized gas(s)(l)(g)
4sToP & tHinKWhich state or states of matter take(s) the shape of its container?Which state or states of matter can change in volume (without adding or subtracting from the sample)?
5Physical ChangesPhysical changes alter a substance without changing its composition
6sToP & tHinK Which of the following are physical properties? liquid at room temperaturereacts with metals to form H2 gasacids and bases combine to form water and a ‘salt’boils at 145 degrees Celsius
7(2.2) Mixtures…Mixture - a combination of two or more pure substances, in which each substance retains its individual chemical propertiesHeterogeneous mixture - does not blend smoothly, individual substances are distinctHomogeneous mixture - solution; has a constant composition throughout
9Separating MixturesFiltration - porous barrier separates solid from liquidDistillation - liquids separated by differences in boiling pointCrystallization - forms pure solids from dissolved substancesChromatography - separation based on ability to travel or be drawn across a material
14sToP & tHinKWhat separation technique is shown in the following pictures?BA
15(2.3) Elements & Compounds Elements - pure substances that cannot be broken down into simpler substanceson the Periodic Table!Compounds - two or more elements bonded together that can be broken down
16sToP & tHinKIn your own words, what is the difference between an element and a compound?Classify the following as being elements or compoundsSodiumSodium chlorideOxygenCarbon dioxideCopper
17(2.4) Chemical Properties the ability of a substance to undergo chemical changeExamples: “reacts with oxygen to form rust”, “forms a deep blue solution when in contact with ammonia”
18Chemical ChangesChemical changes alter the composition so that a new substance formsEvidence of chemical change: formation of a gas or solid (precipitate), smoke, fire, an odor, temperature change, color changeLaw of Conservation of Mass: composition changes, but mass doesn’t
19sToP & tHinKSubstance A is a yellow liquid and substance B is a blue liquid. The two are mixed and form a green liquid and a white solid.What evidence suggests a chemical change occurred?What other things could you look for to determine if there was a chemical change?
20sToP & tHinK - which shows physical change and which shows chemical change? link to change animation #1link to change animation #2