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
3 States 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)
4 sToP & 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)?
5 Physical ChangesPhysical changes alter a substance without changing its composition
6 sToP & 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
9 Separating 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
14 sToP & 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
16 sToP & 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”
18 Chemical 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
19 sToP & 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?
20 sToP & tHinK - which shows physical change and which shows chemical change? link to change animation #1link to change animation #2