4 Intensive and Extensive Properties Physical and chemical properties may be intensive or extensive.
5 What are intensive properties? Intensive properties such as density, color, and boiling point do not depend on the size of the sample of matter and can be used to identify substances.
6 What are extensive properties? Extensive properties such as mass and volume do depend on the quantity of the sample.
7 How can we identify physical properties? Physical properties are those that we can determine without changing the identity of the substance we are studying.
8 Examples of physical properties: The physical properties of sodium metal can be observed or measured. It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.Hardness, color, melting point and density are all physical properties.
9 What is a physical change? A physical change occurs when the substance changes state but does not change its chemical composition. For example: water freezing into ice, cutting a piece of wood into smaller pieces, etc. The form or appearance has changed, but the properties of that substance are the same (i.e. it has the same melting point, boiling point, chemical composition, etc.)Definition of physical changes.
10 Characteristics of Physical Changes DensityElectrical conductivitySolubilityAdsorption to a surfaceHardnessMelting pointBoiling pointVapor pressureColorState of matterPhysical changes are characterized by the following:
11 What are chemical properties? Chemical properties describe the way a substance can change or react to form other substances. These properties, then, must be determined using a process that changes the identity of the substance of interest.
12 CHEMICAL PROPERTIESA chemical property must describe how some substance REACTS or DOES NOT REACT with other substances.In other words, they describe how a substance will be changed or will not be changed when it interacts with other substances.
13 How can chemical properties be identified? One of the chemical properties of alkali metals such as sodium and potassium is that they react with water. To determine this, we would have to combine an alkali metal with water and observe what happens.In other words, we have to define chemical properties of a substance by the chemical changes it undergoes.
14 What are chemical changes? A chemical change occurs when a substance changes into something new. This occurs due to heating, chemical reaction, etc. You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. Many common signs of a chemical change can be seen (change in color, change in temperature, formation of a gas, emission of light, formation of a precipitate).Definition of chemical change.
15 Characteristics of Chemical Changes Reaction with acidsReaction with bases (alkalis)Reaction with oxygen (combustion)Ability to act as oxidizing agentAbility to act as reducing agentReaction with other elementsDecomposition into simpler substancesCorrosionChemical Changes are characterized by the following:
16 Evidence of Chemical Change Bubbles of gas appearA precipitate formsA color change occursThe temperature changesLight is emittedEvidence of Chemical Change
17 Comparison of Physical and Chemical Properties Create a Venn diagram to compare and contrast physical and chemical properties
18 Two Important Physical Properties States of MatterDensity of MatterTwo Important Physical Properties
19 (And how the Kinetic Molecular Theory affects each) States of Matter(And how the Kinetic Molecular Theory affects each)SolidsLiquidsGasesPlasma
21 Kinetic Molecular Theory SolidsHave a definite shapeHave a definite volumeKinetic Molecular TheoryMolecules are held close together and there is very little movement between them.
22 LiquidsHave an indefinite shapeHave a definite volumeKinetic Molecular Theory:Atoms and molecules have more space between them than a solid does, but less than a gas (ie. It is more “fluid”.)
23 GasesHave an indefinite shapeHave an indefinite volumeKinetic Molecular Theory:Molecules are moving in random patterns with varying amounts of distance between the particles.
24 Kinetic Molecular Model of Water At 100°C, water becomes water vapor, a gas. Molecules can move randomly over large distances.Between 0°C and 100 °C, water is a liquid. In the liquid state, water molecules are close together, but can move about freely.Below 0°C, water solidifies to become ice. In the solid state, water molecules are held together in a rigid structure.
26 On earth we live upon an island of "ordinary" matter On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. We have learned to work, play, and rest using these familiar states of matter. Sir William Crookes, an English physicist, identified a fourth state of matter, now called plasma, in 1879.
27 PlasmaPlasma is by far the most common form of matter. Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible.
28 EXAMPLES:Computer chips and integrated circuitsComputer hard drivesElectronicsMachine toolsMedical implants and prostheticsAudio and video tapesAircraft and automobile engine partsPrinting on plastic food containersEnergy-efficient window coatingsHigh-efficiency window coatingsSafe drinking waterVoice and data communications componentsAnti-scratch and anti-glare coatings on eyeglasses and other optics
29 Density Note ml = cm3 Density = mass (g) D = g or g volume (ml) ml cm3
30 Learning Check D1Osmium is a very dense metal. What is its density in g/cm3 if g of the metal occupies a volume of 2.22cm3? 1) 2.25 g/cm3 2) 22.5 g/cm3 3) 111 g/cm3lecturePLUS Timberlake
31 Solution2) Placing the mass and volume of the osmium metal into the density setup, we obtain D = mass = g = volume 2.22 cm3 = g/cm3 = 22.5 g/cm3lecturePLUS Timberlake
32 Volume DisplacementA solid displaces a matching volume of water when the solid is placed in water. 33 mL 25 mLlecturePLUS Timberlake
33 Learning Check 1) 0.2 g/ cm3 2) 6 g/m3 3) 252 g/cm3 What is the density (g/cm3) of 48 g of a metal if the metal raises the level of water in a graduated cylinder from 25 mL to 33 mL?1) 0.2 g/ cm ) 6 g/m ) g/cm333 mL25 mLlecturePLUS Timberlake
34 Solution2) 6 g/cm3 Volume (mL) of water displaced = 33 mL - 25 mL = 8 mL Volume of metal (cm3) = 8 mL x 1 cm3 = 8 cm3 1 mL Density of metal = mass = 48 g = 6 g/cm3 volume 8 cm3lecturePLUS Timberlake
35 Learning Check3 K V W V K W W V K 1) 2) 3) Which diagram represents the liquid layers in the cylinder?(K) Karo syrup (1.4 g/mL), (V) vegetable oil (0.91 g/mL,) (W) water (1.0 g/mL)1) 2) 3)KVWKVWWVKlecturePLUS Timberlake
36 Solution(K) Karo syrup (1.4 g/mL), (V) vegetable oil (0.91 g/mL,) (W) water (1.0 g/mL)1)VWKlecturePLUS Timberlake