Chapter 1: Introduction Classification of Matter Matter can exist in different forms or phases: (1) States of Matter

Chapter 1: Introduction Classification of Matter

Chapter 1: Introduction Classification of Matter Solid Liquid Gas Defined shape? Defined volume? Distance between molecules? Compressible?

Chapter 1: Introduction Classification of Matter (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures Molecules: atom

Chapter 1: Introduction Classification of Matter Elements: (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

Chapter 1: Introduction Classification of Matter Compounds: (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

Chapter 1: Introduction Classification of Matter Pure Substance: (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

Chapter 1: Introduction Classification of Matter Mixtures: (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

Chapter 1: Introduction Classification of Matter Homogeneous Mixtures Heterogeneous Mixtures (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures Air Oil on water

Chapter 1: Introduction Classification of Matter (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures Molecules or atoms? Compound? Phase state? Mixture? - what kind? HW: 1, 2

Chapter 1: Introduction Homogenous or Heterogeneous Mixtures? Granite Mud Coffee - a Coffee - b Water and flour Vinaigrette Brass HW: 9, 15

Chapter 1: Introduction

Mixtures can be separated Filtration Distillation Chromatography... for example by

Chapter 1: Introduction Properties of Matter Physical Properties & Changes Chemical Properties & Changes → no change in identity or composition of substance → how a substance reacts to form a different substance

Chapter 1: Introduction Properties of Matter Melting of ice: Burning of wood: HW: 17, 19

Chapter 1: Introduction Physical of Chemical Property? Zinc (Zn): ● silver-grey metal ● melting point: 420 o C ● generates hydrogen when dissolved in sulfuric acid ● density (25 o C) = 7.13 g/cm 3 ● reacts with oxygen to form Zinc oxide (ZnO)

Chapter 1: Introduction Physical or Chemical Process? Sugar dissolving in water. a) compounds in the gas phase b) elements in the gas phase c) molecules in the gas phase d) a heterogeneous mixture of elements e) a mixture of molecules in the liquid phase The picture on the left represents

Chapter 1: Introduction Intensive Properties… …are independent of the amount of substance Extensive Properties… …depend on the amount of substance Boiling/melting point (bp/mp) Mass Volume Density

Chapter 1: Introduction A gold nugget (1cm x 0.5 cm x 0.7 cm) has a density of 19.3 g/cm 3. A jeweler decides to use this gold nugget to make a perfect gold Sphere with a diameter of 0.4cm. What is the density of this sphere?

Chapter 1: Introduction Units of Measurement: Temperature K = O C + 273

Chapter 1: Introduction Units of Measurement Système International d'Unités (SI units) Masskilogramkg Lengthmeterm Timeseconds TemperatureKelvinK Amount of a substancemolemol

Chapter 1: Introduction Units of Measurement Prefixes used in the metric system: You ABSOLUTELY MUST know these (Table 1.5 page 14): GigaGgigameter (Gm) = 10 9 m MegaMmegameter (Mm) = 10 6 m KiloKkilometer (Km)= 10 3 m meter (m)= 1 m Deciddecimeter (dm)= m Centiccentimeter (cm)= m Millimmillimeter (mm)= m Microµmicrometer (µm)= m Nanonnanometer (nm)= m Picoppicometer (pm)= m Femtoffemtometer(fm)= m

Chapter 1: Introduction Units of Measurement: Derived Units Volume: 1m (1 m) 3 = 1m 3 = 1cubic meter 1cm (1 cm) 3 = 1cm 3 = 1cubic centimeter = 1mL

Chapter 1: Introduction Units of Measurement: Derived Units ● Generally expressed as g/mL or g/cm 3 ● Depend on temperature HW: 24, 29

Chapter 1: Introduction Dimensional Analysis Converting inches into cm: - the units to be eliminated go on opposite sides of the fraction Conversion factor: same quantity but in different units Converting m/min into m/s: Conversion factor HW: 49, 52

Chapter 1: Introduction Dimensional Analysis More than one conversion: A car travels 12 km per liter of gasoline. How many many miles per gallon will it go? =>Convert 12 km/L into mi/gallon =>first, convert length units: km into mi, second, convert volume units: L into gallons or (1)

Chapter 1: Introduction Dimensional Analysis More than one conversion: A car travels 12 km per liter of gasoline. How many many miles per gallon will it go? =>Convert 12 km/L into mi/gallon (1) or (2) =>first, convert length units: km into mi, second, convert volume units: L into gallons

Chapter 1: Introduction Dimensional Analysis More than one conversion: A car travels 12 km per liter of gasoline. How many many miles per gallon will it go? =>Convert 12 km/L into mi/gallon (1) (2) Correct number of sig. figs. =>first, convert length units: km into mi, second, convert volume units: L into gallons

Chapter 1: Introduction Dimensional Analysis More than one conversion: A car travels 12 km per liter of gasoline. How many many miles per gallon will it go? =>Convert 12 km/L into mi/gallon =>first, convert length units: km into mi, second, convert volume units: L into gallons => with more PRACTICE you can combine steps (1) and (2):

Chapter 1: Introduction Dimensional Analysis Conversions involving squared and cubic units: The volume of a container is 5.3 m 3. What is the volume in cm 3 ? =>Convert m 3 into cm 3 Units must match in order to cancel out!

Chapter 1: Introduction Dimensional Analysis Conversions involving squared and cubic units: The volume of a container is 5.3 m 3. What is the volume in cm 3 ? =>Convert m 3 into cm 3 Units must match = cube both number AND unit !

Chapter 1: Introduction Uncertainty in Measurement Inexact Numbers Exact Numbers Obtained by measurement Value is known precisely HW: 35 The temperature of the asphalt on Randall Drive today? The number of mm in one yd of speaker cable ? Mass of 1L of milk?

Chapter 1: Introduction Uncertainty in Measurement good accuracy good precision poor accuracy good precision poor accuracy poor precision good accuracy poor precision Accuracy: how do the measured values agree with the “true” value? Precision: how reproducible is the measurement?

Chapter 1: Introduction Significant Figures Which digits count? (a) All significant digits in a number Zeros... (b)...between nonzero digits count (c)...in the beginning of a number never count (d)...in the end of a number only count if the is a decimal point sig figs sig figs sig figs 45,0002 sig figs

Chapter 1: Introduction Significant Figures sig figs sig figs sig figs 45,0002 sig figs This is easiest to see when written in exponential notation: = x 0.01 = x = x 0.1 = x ,000 = 4.5 x = 4.5 x 10 4

Chapter 1: Introduction Significant Figures ● Final result is only as accurate as the least accurate measurement ● The least accurate measurement determines the number of sig. figs. (1) Division and Multiplication: volume = 1.32cm x 1.1cm x 3.540cm = cm 3 = 5.1cm 3 velocity = 342 m / 32 s = m/s = 11 m/s Number with fewest sig. figs. determines sig. figs. of answer Answer rounded to 2 sig. figs.

Chapter 1: Introduction Significant Figures ● Final result is only as accurate as the least accurate measurement ● The least accurate measurement determines the number of sig. figs. (2) Addition and Subtraction = Number with fewest decimal places (NOT sig. Figs.) determines answer = answer rounded to 1 decimal point