Why did Chemistry Become a Science?

Transcription

1 Chemistry is a magic or science????? Why did Chemistry Become a Science? Chapter 1

2 Chemical Science is important to us all is the world around us is more than you might have thought is always looking to the future Chapter 1

3 Three questions for KNOWLEDGE : What??? Why??? How??? Chapter 1

4 Observation Representation Interpretation The three levels of studying chemistry and their relationships. Chapter 1

5 The various parts of the scientific method. Chapter 1

6 Matter These are some of the salt crystals collected. Chapter 1

7 Matter - anything that occupies space and has mass. mass measure of the quantity of matter SI unit of mass is the kilogram (kg) 1 kg = 1000 g = 1 x 10 3 g weight force that gravity exerts on an object weight = c x mass on earth, c = 1.0 on moon, c ~ 0.1 A 1 kg bar will weigh 1 kg on earth 0.1 kg on moon Chapter 1

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9 Chapter 1

10 Atom Combinations Chapter 1

11 Classifications of Matter The three states of water: a) Solid ; b) Liquid ; c) Gas. Chapter 1

12 The three forms of the element carbon: a) Diamond; b) Graphite; c) Buckminsterfullerene.

13 solid Physical States fixed volume and shape liquid fixed volume shape of container, horizontal top surface gas takes shape and volume of container liquid crystal some characteristics of solid and some of liquid states

14 macroscale Sample Sizes physical properties that can be observed by the unaided human senses microscale samples of matter that have to be viewed with a microscope nanoscale samples that are at the atomic or molecular scale where chemical reactions occur

15 Physical or Chemical? A physical change does not alter the composition or identity of a substance. sugar dissolving ice melting in water A chemical change alters the composition or identity of the substance(s) involved. hydrogen burns in air to form water

16 The composition of air. Air composition

17 Electrolysis, the decomposition of water by an electric current, is a chemical process.

18 Chart examining each substance of air.

19 Gold Twenty-four-karat gold is an element; Eighteen-karat gold is an alloy; Fourteen-karat gold is an alloy.

20 The solution is boiled and steam is driven off.

21 Salt remains after all water is boiled off.

22 No chemical change occurs when salt water is distilled.

23 Filtration separates a liquid from a solid.

24 Separation of a sand-saltwater mixture.

25 The organization of matter.

26 Law of Conservation of Matter In an ordinary chemical reaction matter is neither created nor destroyed. The sum of the masses of the reactants equals the sum of the masses of the products.

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28 Measurements and Calculations

29 Extensive and Intensive Properties An extensive property of a material depends upon how much matter is being considered. mass length volume An intensive property of a material does not depend upon how much matter is being considered. density temperature color

30 Comparison of English and metric units.

31 Measuring a pin.

32 Base Quantity Name of Unit Symbol Length meter m Mass Kilogram kg Time second s Electrical current ampere A Temperature kelvin K Amount of substance mole mol Luminous intensity candela cd Prefix Symbol Meaning Example Tera- T 1,000,000,000,000 or Terameter(Tm)=m? Giga- G 1,000,000,000, or Gigagrame (Gg)=g? =kg? Mega- M 1,000,000, or Megameter(Mm) =m? Kilo- k 1000, or kilometer(km) =m? Deci- d 1/10 or 10-1 Centi- c 1/100 or 10-2 Milli- m 1/1000 or 10-3 Micro- µ 1/1000,000,or 10-6 Nano- n 1/1000,000,000, or 10-9 Pico- p 1/1000,000,000,000, or 10-12

33 Volume Volume: is length (m) cubed, so the SI-derived Unit is the cubic meter(m 3 ) Cube representations, A 100 ml graduated cylinder.

34 Density Density: isthe mass of an object divided by its volume. Density:=mass/volume or d=m/v

35 Density SI derived unit for density is kg/m 3 1 g/cm 3 = 1 g/ml = 1000 kg/m 3 density = mass volume d = m V A piece of platinum metal with a density of 21.5 g/cm 3 has a volume of 4.49 cm 3. What is its mass? d = m V m = d x V = 21.5 g/cm 3 x 4.49 cm 3 = 96.5 g

36 Earlier in that century, Fahrenheit and Celsius used water as the basis of their thermometers. Their thermometers were calibrated using water, which everyone had access to. This made their thermometers useful.

37 The three major temperature scales.

38 K=( C C)X1K/1 C Converting 70 degrees Celsius to Kelvin units.

39 C=( F-32 F)X5/9 F=9/5X( C)+32 F Comparison of the Celsius and Fahrenheit scales.