CHAPTER 6 PROPERTIES OF MATTER

1. CHAPTER 6PROPERTIES OF MATTER CHEMISTRY – DACS 1232 LECTURER IMRAN SYAKIR MOHAMAD │MOHD HAIZAL MOHD HUSIN │ NONA MERRY MERPATI MITAN

2. Three States of Matter

3. H2O (l) H2O (g) H2O (s) H2O (l) H2O (s) H2O (g) Phase Changes Phase changes, trans-formations from one phase to another, occur when energy (usually in the form of heat) is added or removed. 3 Phases Gas phase - steam Liquid phase - water Solid phase - ice

4. Phase Changes Condensation Melting solid  liquid Evaporation Freezing liquid  solid Vaporization liquid  gas Deposition Sublimation Condensation gas  liquid Freezing Melting Sublimation solid  gas Deposition gas  solid

6. Phase Diagram of Water A phase diagram summarizes the conditions at which a substance exists as a solid, liquid, or gas.

7. Gases Physical Characteristics of Gases • 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.

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

10. Force Pressure = Area Units of Pressure 1 pascal (Pa) = 1 N/m2 1 atm = 760 mmHg = 760 torr 1 atm = 101,325 Pa Barometer

11. 10 miles 0.2 atm 4 miles 0.5 atm Sea level 1 atm

12. V decreases As P (h) increases

13. Constant temperature Constant amount of gas Boyle’s Law Pa 1/V P x V = constant P1 x V1 = P2 x V2

14. 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?

15. P V Chemistry in Action: Scuba Diving and the Gas Laws

16. Charles’ & Gay-Lussac’s Law As T increases V increases

17. Temperature must be in Kelvin Variation of gas volume with temperature at constant pressure. VaT V = constant x T V1/T1 = V2/T2 T (K) = t (0C) + 273.15

18. 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?

19. Constant temperature Constant pressure Avogadro’s Law Va number of moles (n) V = constant x n V1/n1 = V2/n2

20. 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?

21. Boyle’s law: V a (at constant n and T) Va nT nT nT P P P V = constant x = R 1 P Ideal Gas Equation Charles’ law: VaT(at constant n and P) Avogadro’s law: V a n(at constant P and T) R is the gas constant PV = nRT

22. The conditions 0 0C and 1 atm are called standard temperature and pressure (STP). R = (1 atm)(22.4L) PV = nT (1 mol)(273.15 K) Experiments show that at STP, 1 mole of an ideal gas occupies 22.4 L. PV = nRT R = 0.082057 L • atm / (mol • K)

23. What is the volume (in liters) occupied by 49.8 g of HCl at STP?

24. d = Density (d) Calculations = RT PV = nRT m is the mass of the gas in g = dRT PM = RT m m m V V M M is the molar mass of the gas Molar Mass (M ) of a Gaseous Substance PM d = RT dRT M = d is the density of the gas in g/L P

25. 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) Gas Stoichiometry

26. Liquids Properties of Liquids Surface tension is the amount of energy required to stretch or increase the surface of a liquid by a unit area. Strong intermolecular forces High surface tension

27. Adhesion Cohesion Cohesion is the intermolecular attraction between like molecules Adhesion is an attraction between unlike molecules When 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. water mercury

28. Viscosity is a measure of a fluid’s resistance to flow. Strong intermolecular forces High viscosity

29. lattice point Solids • A crystalline solid possesses rigid and long-range order. In a crystalline solid, atoms, molecules or ions occupy specific (predictable) positions. • An amorphoussolid 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 Cell Unit cells in 3 dimensions

34. Shared by 2 unit cells Shared by 8 unit cells

35. 4 atoms/unit cell 2 atoms/unit cell 1 atom/unit cell (8 x 1/8 + 6 x 1/2 = 4) (8 x 1/8 + 1 = 2) (8 x 1/8 = 1)

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

39. Extra distance = = nl 2d sinq BC + CD = (Bragg Equation)

40. 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?

41. Types of Crystals Ionic Crystals • Lattice points occupied by cations and anions • Held together by electrostatic attraction • Hard, brittle, high melting point • Poor conductor of heat and electricity CsCl ZnS CaF2

42. carbon atoms Types of Crystals Covalent Crystals • Lattice points occupied by atoms • Held together by covalent bonds • Hard, high melting point • Poor conductor of heat and electricity graphite diamond

43. Types of Crystals Molecular Crystals • Lattice points occupied by molecules • Held together by intermolecular forces • Soft, low melting point • Poor conductor of heat and electricity

44. nucleus & inner shell e- mobile “sea” of e- Types of Crystals Metallic Crystals • Lattice points occupied by metal atoms • Held together by metallic bonds • Soft to hard, low to high melting point • Good conductors of heat and electricity Cross Section of a Metallic Crystal

45. Types of Crystals