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Properties of MattersChapter 5

CHEMISTRY - DACS 1232Fakulti Kejuruteraan Mekanikal, UTeM

Lecturer:IMRAN SYAKIR BIN MOHAMADMOHD HAIZAL BIN MOHD HUSINNONA MERRY MERPATI MITAN#

Three States of Matter#3 PhasesSolid phase - iceLiquid phase - waterPhase ChangesPhase changes, trans-formations from one phase to another, occur when energy (usually in the form of heat) is added or removed.Gas phase - steamH2O (l) H2O (g)H2O (s) H2O (l)H2O (s) H2O (g)#

EvaporationCondensationMeltingFreezingSublimationDepositionPhase ChangesMelting solid liquidFreezing liquid solidVaporization liquid gasCondensation gas liquidSublimation solid gasDeposition gas solid#

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A phase diagram summarizes the conditions at which a substance exists as a solid, liquid, or gas.Phase Diagram of Water#Gases assume the volume and shape of their containers.Gases are the most compressible state of matter.Gases will mix evenly and completely when confined to the same container.Gases have much lower densities than liquids and solids.Physical Characteristics of GasesGases

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Elements that exist as gases at 25 0C and 1 atmosphere#

#Units of Pressure1 pascal (Pa) = 1 N/m21 atm = 760 mmHg = 760 torr1 atm = 101,325 Pa

BarometerPressure =

ForceArea#

Sea level1 atm4 miles0.5 atm10 miles0.2 atm

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As P (h) increasesV decreases#

P a 1/VP x V = constantP1 x V1 = P2 x V2Boyles LawConstant temperatureConstant amount of gas

#A sample of chlorine gas occupies a volume of 946 mL at a pressure of 726 mmHg. What is the pressure of the gas (in mmHg) if the volume is reduced at constant temperature to 154 mL?#

Chemistry in Action:Scuba Diving and the Gas Laws

PVDepth (ft)Pressure (atm)01332663#

As T increasesV increasesCharles & Gay-Lussacs Law#

Variation of gas volume with temperature at constant pressure.V a TV = constant x TV1/T1 = V2/T2T (K) = t (0C) + 273.15 Temperature must bein Kelvin

#A sample of carbon monoxide gas occupies 3.20 L at 125 0C. At what temperature will the gas occupy a volume of 1.54 L if the pressure remains constant?#Avogadros LawV a number of moles (n)V = constant x nV1/n1 = V2/n2

Constant temperatureConstant pressure

#Ammonia burns in oxygen to form nitric oxide (NO) and water vapor. How many volumes of NO are obtained from one volume of ammonia at the same temperature and pressure?#Ideal Gas EquationCharles law: V a T (at constant n and P)Avogadros law: V a n (at constant P and T)Boyles law: V a (at constant n and T)1PV a nTPV = constant x = RnTPnTPR is the gas constantPV = nRT#The conditions 0 0C and 1 atm are called standard temperature and pressure (STP).

PV = nRTR = PVnT=(1 atm)(22.4L)(1 mol)(273.15 K)R = 0.082057 L atm / (mol K)Experiments show that at STP, 1 mole of an ideal gas occupies 22.4 L.

#What is the volume (in liters) occupied by 49.8 g of HCl at STP?#Molar Mass (M ) of a Gaseous SubstancedRTPM =d is the density of the gas in g/LDensity (d) Calculationsd = mVd = PMRTm is the mass of the gas in gM is the molar mass of the gasPV = nRT= RT mMPM = RTmV= dRT #Gas Stoichiometry

What is the volume of CO2 produced at 370 C and 1.00 atm when 5.60 g of glucose are used up in the reaction:C6H12O6 (s) + 6O2 (g) 6CO2 (g) + 6H2O (l)#Properties of LiquidsSurface tension is the amount of energy required to stretch or increase the surface of a liquid by a unit area.Strong intermolecular forcesHigh surface tension

Liquids#Cohesion is the intermolecular attraction between like moleculesAdhesion is an attraction between unlike molecules

AdhesionCohesionWhen adhesion is greater than cohesion, the liquid rises in the capillary tube. When cohesion is greater than adhesion, a depression of the liquid in the capillary tube. watermercury#Viscosity is a measure of a fluids resistance to flow.Strong intermolecular forcesHigh viscosity

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A crystalline solid possesses rigid and long-range order. In a crystalline solid, atoms, molecules or ions occupy specific (predictable) positions. An amorphous solid does not possess a well-defined arrangement and long-range molecular order.A unit cell is the basic repeating structural unit of a crystalline solid.Unit CelllatticepointUnit cells in 3 dimensionsSolids#

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Shared by 8 unit cellsShared by 2 unit cells#

1 atom/unit cell(8 x 1/8 = 1)2 atoms/unit cell(8 x 1/8 + 1 = 2)4 atoms/unit cell(8 x 1/8 + 6 x 1/2 = 4)#

#When silver crystallizes, it forms face-centered cubic cells. The unit cell edge length is 409 pm. Calculate the density of silver.#

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Extra distance =BC + CD =2d sinq= nl(Bragg Equation)#X rays of wavelength 0.154 nm are diffracted from a crystal at an angle of 14.170. Assuming that n = 1, what is the distance (in pm) between layers in the crystal?#Types of CrystalsIonic CrystalsLattice points occupied by cations and anionsHeld together by electrostatic attractionHard, brittle, high melting pointPoor conductor of heat and electricity

CsClZnSCaF2#Types of CrystalsCovalent CrystalsLattice points occupied by atomsHeld together by covalent bondsHard, high melting pointPoor conductor of heat and electricity

diamondgraphitecarbonatoms#Types of CrystalsMolecular CrystalsLattice points occupied by moleculesHeld together by intermolecular forcesSoft, low melting pointPoor conductor of heat and electricity

#Types of CrystalsMetallic CrystalsLattice points occupied by metal atomsHeld together by metallic bondsSoft to hard, low to high melting pointGood conductors of heat and electricity

Cross Section of a Metallic Crystalnucleus &inner shell e-mobile seaof e-#

Types of Crystals#