Gen-Chem110-Ch01

Chapter 1 The Foundations of Chemistry HW27Qs: 3, 4, 6, 10, 14,18, 20, 26, 28, 30, 32, 34, 36, 38, 40, 44, 46, 50, 54, 56, 58, 60, 62, 64, 66, 68,70 Dr. Shiunchin C. Wang

1.1 Matter and Energy CHEMISTRY MATTER What is Chemistry? Chemistry is the science that describe matter regarding with its composition, structure, properties. matter is anything has mass and occupies space . Mass Occupies Space + Mass is a measurement of the quantity of matter in a sample of any materials. Mass is different from weight. Mass does not vary in different place, but weight does. Weight : a measurement of the gravitational attraction of the earth for the body. Volume: a 3-D space. Subdiscipline of chemistry: Analytical, Biological, Biophysical, Inorganic, Organic, Material, Physical, Polymer, Nanotechnology etc.

1.1 Matter and Energy (Cont.) ,[object Object],[object Object],Types of Energy: Electrical energy (electrical power), thermal energy (heat), nuclear energy (energy release from nucleus of atom, E=mc 2 ), & chemical energy (associate with atoms).

Natural Laws ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

1.1 Matter and Energy (Cont.) Law of Conservation of Energy : Energy cannot be created or destroyed in a chemical reaction or in a physical change. It can only be converted from one form to another . Relationship between matter and energy by Albert Einstein in 1940: E= mc 2 Exothermic reaction : convert chemical energy into heat energy. Endothermic reaction : heat, light, and electrical energy can be converted into chemical energy

1.1 Endothermic vs. Exothermic ,[object Object],Endo thermic reaction : reactions that absorb energy from surrounding (heat, light, electrical energy) to from chemical energy. H 2 O(s) + 6.02 kJ  H 2 O(l) solid ice liquid water

1.2 Chemistry – A molecular View of Matter

Non-Mixtures: Elements Atom: smallest particle of an element. Atoms consists 3 fundamental particles: electrons, protons, neutrons.

Non-Mixtures: Compounds ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

(p.8) Ex. 1.1 distinguish different matters ,[object Object],[object Object],[object Object],[object Object],atom molecule element compound Krypton, Kr V V V X Ethane, C 2 H 6 X V X V Nitrogen, N 2 X V V X Aspirin, C 9 H 8 O 4 X V X V Sulfur dioxide, SO 2 X V X V Mole of copper , Cu = 6.022 x 10 23 particles X X V X

1-4 Chemical and Physical Properties ,[object Object],[object Object],[object Object],[object Object],[object Object],T (melting) = T (freezing) T (evaporation) = T (condensation) T (deposition) = T (sublimation)

1-7 Measurements in Chemistry ,[object Object],[object Object],[object Object],[object Object],Example: 1 mole of gold = 197 gram of gold 1 mole of gold = 6.022 X 10 23 atoms of gold = 602,200,000,000,000,000,000,000 Mass of gold = 3.27 X 10 -27 gram = 0.000 000 000 000 000 000 000 327 gram

Significant Figures (p 23) Determination of 123,000 significant figures: (1) 1.23 x 10 5 has 3 significant figures, (2) 1.230 x 10 5 has 4 significant figures. Special case: 24 0 000 has 3 significant figures. Therefore, it is best to use “scientific notation” to represent the significant figures. In this case will be 2.40 X 10 5 . Note: Measurement of volumetric cylinder by reading the bottom of the meniscus . Significant Figures = Exact numbers + 1 estimate number

1-10 The Unit Factor Method ,[object Object],Q 1.47 mi = ? in 1 L = 1000 mL = 1 dm 3 || 1 mL = 1 cm 3 = 1 cc 1 gal = 4 qt = 8pt || 1 qt = 0.964 L

1-12 Density & Specific Gravity ,[object Object],[object Object],Q. What is the density of 47.3 mL ethyl alcohol (= ethanol) with mass 37.32 g? A. d = m/V = 37.32 g/ 47.3mL = 0.789 g/mL Specific Gravity (SG.): is the ratio of its density to the density of water ,[object Object],[object Object],[object Object],[object Object]

1.13 Heat and Temperature ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

1.14 Heat Transfer and the Measurement of Heat ,[object Object],[object Object],Heat Energy: Q = m c  T Q (joule, J) = Heat Energy; where 1calorie = 4.184 joule m = mass (gram) c = Specific heat = J/g  C; C(ice) = 2.09 J/g  C C (water) = 4.18 J/g  C C (steam) = 2.03 J/g  C  T = change of temperature Heat Capacity = C = Q/∆T

[object Object],[object Object],[object Object],(Ex 1.21) A 588-gram chunk or iron is heated to 97.5  C. Then it is immersed in 247 grams of water originally at 20.7  C. When thermal equilibrium has been reached, the water and iron are both at 36.2  C. Calculate the specific heat of iron. Ans T final = 36.2  C [(588 g) (c) (97.5 – 36.2  C)] iron = [(247 g) (4.18J/g  C) (36.2 - 20.7  C)] water specific heat of iron, c = 0.444 J/g  C Thermal Equilibrium Heat gained = eat lost (m c  T) gained = (m c  T) lost

Gen-Chem110-Ch01

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